rifampin/isoniazid (Discontinued)

Tuberculosis

Indicated for pulmonary tuberculosis in which organisms are susceptible, and when the patient has been titrated on the individual components and it has therefore been established that this fixed dosage is therapeutically effective

Rifampin 600 mg/isoniazide 300 mg (ie, 2 capsules) PO qDay

Dosing Considerations

This fixed-dosage combination drug is not recommended for initial therapy of tuberculosis or for preventive therapy

<15 years: Safety and efficacy not established

Contraindicated (57)

• artemether/lumefantrine

  rifampin will decrease the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration with strong CYP3A4 inducers can result in decreased serum concentrations and loss of antimalarial efficacy

• atazanavir

  rifampin decreases levels of atazanavir by increasing metabolism. Contraindicated. Contraindicated. May result in loss of antiviral efficacy and/or development of viral resistance.

• bictegravir

  rifampin will decrease the level or effect of bictegravir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of strong CYP3A and UGT1A1 inducers can substantially decrease bictegravir plasma concentrations. This may result in the loss of therapeutic effect and development of resistance to bictegravir. Coadministration with rifampin is contraindicated.

• cabotegravir

  rifampin will increase the level or effect of cabotegravir by increasing metabolism. Contraindicated. Cabotegravir is metabolized by UGT1A1 and UGT1A9. Strong UGT1A1 or UGT1A9 inducers decrease cabotegravir systemic exposure, thereby increasing potential for loss of virologic response.

• cariprazine

  rifampin will decrease the level or effect of cariprazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. CYP3A4 is responsible for the formation and elimination of cariprazine's active metabolites. The effect of CYP3A4 inducers on cariprazine exposure has not been evaluated and the net effect is unclear.

• cobicistat

  rifampin will decrease the level or effect of cobicistat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration with rifampin is contraindicated due to potential for loss of therapeutic effect and development of resistance.

• cobimetinib

  rifampin will decrease the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid coadministration. Strong or moderate CYP3A inducers may decrease cobimetinib systemic exposure by >80% and reduce its efficacy.
  
  isoniazid will increase the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid coadministration with strong CYP3A4 inhibitors with (increases cobimetinib systemic exposure by 6.7-fold).

• conivaptan

  isoniazid will increase the level or effect of conivaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of conivaptan with strong CYP3A4 inhibitors is contraindicated.

• darunavir

  rifampin decreases levels of darunavir by increasing metabolism. Contraindicated. Contraindicated. May result in loss of antiviral efficacy and/or development of viral resistance.

• dihydroergotamine

  isoniazid will increase the level or effect of dihydroergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• dihydroergotamine intranasal

  isoniazid will increase the level or effect of dihydroergotamine intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• doravirine

  rifampin will decrease the level or effect of doravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of doravirine with a strong CYP3A inducer may decrease doravirine plasma concentrations and/or effects. Potential for loss of virologic response and possible resistance to doravirine.

• elbasvir/grazoprevir

  rifampin will decrease the level or effect of elbasvir/grazoprevir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. The therapeutic effect of elbasvir/grazoprevir may be reduced if coadministered with strong CYP3A inducers and is therefore contraindicated.

• eliglustat

  isoniazid will increase the level or effect of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors are contraindicated with eliglustat poor or intermediate metabolizers; reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors
  
  isoniazid increases levels of eliglustat by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated. If coadministered with strong or moderate CYP2D6 inhibitors, reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive and intermediate metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors.

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  rifampin decreases levels of elvitegravir/cobicistat/emtricitabine/tenofovir DF by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. May lead to loss of virologic response and possible resistance.

• etravirine

  rifampin decreases levels of etravirine by increasing metabolism. Contraindicated.

• fezolinetant

  isoniazid will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitors

• flibanserin

  isoniazid will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of flibanserin with moderate or strong CYP3A4 inhibitors is contraindicated. Severe hypotension or syncope can occur.

• fosamprenavir

  rifampin decreases levels of fosamprenavir by increasing metabolism. Contraindicated. Contraindicated. May result in loss of antiviral efficacy and/or development of viral resistance.

• fostemsavir

  rifampin will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

• glecaprevir/pibrentasvir

  rifampin will decrease the level or effect of glecaprevir/pibrentasvir by increasing metabolism. Contraindicated. Coadministration of rifampin (a strong CYP3A4 and P-gp inducer) with glecaprevir/pibrentasvir significantly decreased glecaprevir/pibrentasvir plasma concentrations and AUC. Potential for loss of therapeutic effect.

• infigratinib

  isoniazid will increase the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• irinotecan

  rifampin will decrease the level or effect of irinotecan by affecting hepatic enzyme CYP2B6 metabolism. Contraindicated.

• irinotecan liposomal

  rifampin will decrease the level or effect of irinotecan liposomal by affecting hepatic enzyme CYP2B6 metabolism. Contraindicated.

• isavuconazonium sulfate

  rifampin will decrease the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• ivabradine

  isoniazid will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of ivabradine with strong CYP3A4 inhibitors is contraindicated.

• ketoconazole

  isoniazid decreases levels of ketoconazole by unspecified interaction mechanism. Contraindicated.

• ledipasvir/sofosbuvir

  rifampin will decrease the level or effect of ledipasvir/sofosbuvir by P-glycoprotein (MDR1) efflux transporter. Contraindicated. P-gp inducers decrease sofosbuvir levels, and therefore decrease conversion to sofosbuvir's active metabolite (GS-331007) responsible for 90% of pharmacologic effect

• lenacapavir

  rifampin will decrease the level or effect of lenacapavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of lenacapavir with strong CYP3A inducers is contraindicated.

• levoketoconazole

  isoniazid decreases levels of levoketoconazole by unspecified interaction mechanism. Contraindicated.

• lomitapide

  isoniazid increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Increases lomitapide levels several folds.

• lonafarnib

  rifampin will decrease the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lonafarnib is a sensitive CYP3A4 substrate. Coadministration with strong or moderate CYP3A4 inducers is contraindicated.
  
  isoniazid will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lonafarnib is a sensitive CYP3A4 substrate. Coadministration with strong or moderate CYP3A4 inhibitors is contraindicated.

• lorlatinib

  rifampin will decrease the level or effect of lorlatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of lorlatinib with strong CYP3A inducers is contraindicated. Discontinue the strong CYP3A inducer for 3 plasma half-lives before initiating lorlatinib.

• lovastatin

  isoniazid will increase the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors increase systemic statin exposure and risk of myopathy, including rhabdomyolysis

• lumacaftor/ivacaftor

  rifampin will decrease the level or effect of lumacaftor/ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A inducers have minimal effect on lumacaftor exposure, but decreased ivacaftor exposure (AUC) by 57%. This may reduce the effectiveness of lumacaftor/ivacaftor. Therefore, coadministration is not recommended.

• lumefantrine

  rifampin will decrease the level or effect of lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration with strong CYP3A4 inducers can result in decreased serum concentrations and loss of antimalarial efficacy

• lurasidone

  isoniazid will increase the level or effect of lurasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of lurasidone and strong CYP3A4 inhibitors is contraindicated.
  
  rifampin decreases levels of lurasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of lurasidone with strong CYP3A4 inducers is contraindicated.

• mavacamten

  rifampin will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  rifampin will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  isoniazid will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction.

• naloxegol

  rifampin will decrease the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Use of naloxegol with strong CYP3A4 inducers is not recommended
  
  isoniazid will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of naloxegol with strong CYP3A4 inhibitors can significantly increase naloxegol systemic exposure which may precipitate opioid withdrawal symptoms

• nelfinavir

  rifampin decreases levels of nelfinavir by increasing metabolism. Contraindicated. Decreased nelfinavir plasma concentrations may lead to loss of therapeutic effect and possible development of resistance to nelfinavir or other coadministered antiretroviral agents.

• pacritinib

  isoniazid will increase the level or effect of pacritinib by affecting hepatic enzyme CYP2E1 metabolism. Contraindicated.

• nirmatrelvir

  rifampin will decrease the level or effect of nirmatrelvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Nirmatrelvir, a CYP3A4 substrate, is contraindicated with strong CYP3A4 inducers. Significantly reduced nirmatrelvir plasma concentrations may be associated with potential for loss of virologic response and possible resistance. Do not initiate nirmatrelvir/ritonavir immediately after discontinuing a strong 3A4 inducer owing to time needed for systemic clearance of the inducer.

• nirmatrelvir/ritonavir

  rifampin will decrease the level or effect of nirmatrelvir/ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Nirmatrelvir, a CYP3A4 substrate, is contraindicated with strong CYP3A4 inducers. Significantly reduced nirmatrelvir plasma concentrations may be associated with potential for loss of virologic response and possible resistance. Do not initiate nirmatrelvir/ritonavir immediately after discontinuing a strong 3A4 inducer owing to time needed for systemic clearance of the inducer.

• ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)

  rifampin will decrease the level or effect of ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) by increasing metabolism. Contraindicated. Strong CYP2C8 inducers may reduce dasabuvir levels, and therefore decreased efficacy of Viekira Pak
  
  rifampin will decrease the level or effect of ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inducers may reduce partiaprevir and ritonavir levels, and therefore decreased efficacy of Viekira Pak

• panobinostat

  rifampin decreases levels of panobinostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inducers can reduce panobinostat levels by ~70% and lead to treatment failure.

• pirfenidone

  rifampin will decrease the level or effect of pirfenidone by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Use of strong CYP1A2 inducers should be discontinued before initiating pirfenidone and avoided during treatment

• praziquantel

  rifampin decreases levels of praziquantel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP450 inducers significantly decrease praziquantel blood levels.

• regorafenib

  rifampin, regorafenib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inducers decrease regorafenib levels and increase exposure of the active metabolite M-5.
  
  isoniazid, regorafenib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors increase regorafenib levels and decrease exposure of the active metabolites M-2 and M-5.

• rilpivirine

  rifampin decreases levels of rilpivirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindicated. Rilpivirine should not be co-administered with strong CYP 3A4 inducers. Potential for loss of virologic response and possible resistance to rilpivirine or to the NNRTI class.

• venetoclax

  isoniazid will increase the level or effect of venetoclax by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Use of strong CYP3A4 inhibitors is contraindicated with venetoclax during the initial ramp-up dosing phase. If a strong CYP3A inhibitor must be used after the ramp-up phase, reduce the venetoclax dose by at least 75%.

• roflumilast

  rifampin will decrease the level or effect of roflumilast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration not recommended; strong cytochrome P450 enzyme inducers decrease systemic exposure to roflumilast and may reduce the therapeutic effectiveness
  
  rifampin will decrease the level or effect of roflumilast by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Coadministration not recommended; strong cytochrome P450 enzyme inducers decrease systemic exposure to roflumilast and may reduce the therapeutic effectiveness

• saquinavir

  rifampin will decrease the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindicated. May result in loss of antiviral efficacy and/or development of viral resistance.
  
  rifampin increases toxicity of saquinavir by unspecified interaction mechanism. Contraindicated. Adding rifampin to saquinavir/ritonaivr (ritonavir boosted saquinavir) may result in toxic hepatitis.

• tipranavir

  rifampin will decrease the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindicated. May result in loss of antiviral efficacy and/or development of viral resistance.

• vandetanib

  rifampin decreases levels of vandetanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid coadministration with potent CYP3A4 inducers; these drugs reduce exposure to vandetanib by up to 40%.

• velpatasvir

  rifampin will decrease the level or effect of velpatasvir by affecting hepatic enzyme CYP2B6 metabolism. Contraindicated.

• voclosporin

  isoniazid will increase the level or effect of voclosporin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• voriconazole

  rifampin decreases levels of voriconazole by increasing metabolism. Contraindicated.

Serious - Use Alternative (283)

• abametapir

  abametapir will increase the level or effect of rifampin by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP2B6 substrates. If not feasible, avoid use of abametapir.

• abemaciclib

  rifampin will decrease the level or effect of abemaciclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of abemaciclib with strong CYP3A4 inducers reduces plasma concentration of abemaciclib and its metabolites.

• abrocitinib

  rifampin will decrease the level or effect of abrocitinib by increasing metabolism. Avoid or Use Alternate Drug. Abrocitinib is a CYP2C9 and CYP2C19 substrate. Drugs that are strong inducers of CYP2C19 or CYP2C9 decreases the combined exposure of abrocitinib and its active metabolites, resulting in loss of or reduced clinical response.

• acalabrutinib

  rifampin will decrease the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of acalabrutinib with strong CYP3A inducers. If a strong CYP3A inducer must be used, increase acalabrutinib dose to 200 mg twice daily.
  
  isoniazid will increase the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of acalabrutinib with strong CYP3A inhibitors. If a strong CYP3A inhibitor must be used short-term (eg, up to 7 days), temporarily interrupt treatment with acalabrutinib.

• adagrasib

  rifampin will decrease the level or effect of adagrasib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ado-trastuzumab emtansine

  isoniazid increases levels of ado-trastuzumab emtansine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. DM1, the cytotoxic component, is metabolized mainly by CYP3A4; strong CYP3A4 inhibitors may increase DM1 exposure and toxicity.

• afatinib

  rifampin decreases levels of afatinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Increase afatinib daily dose by 10 mg as tolerated if chronic therapy with P-gp inducer required; resume previous afatinib dose 2-3 days after P-gp inducer discontinued.

• alfentanil

  isoniazid will increase the level or effect of alfentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Monitor for excessive CNS and respiratory depression

• alfuzosin

  isoniazid will increase the level or effect of alfuzosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• almotriptan

  rifampin will decrease the level or effect of almotriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• alpelisib

  rifampin will decrease the level or effect of alpelisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of alpelisib (CYP3A4 substrate) with strong CYP3A4 inducers.

• alprazolam

  rifampin will decrease the level or effect of alprazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• amiodarone

  rifampin will decrease the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• apixaban

  rifampin will decrease the level or effect of apixaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Rifampin, a combined P-gp and strong CYP3A4 inducer, may decrease exposure to apixaban.

• apremilast

  rifampin will decrease the level or effect of apremilast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong CYP inducers results in a significant decrease of systemic exposure of apremilast, which may result in loss of efficacy

• aprepitant

  rifampin will decrease the level or effect of aprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• aripiprazole

  rifampin will decrease the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• atazanavir

  rifampin will decrease the level or effect of atazanavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• atorvastatin

  rifampin will decrease the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin increases toxicity of atorvastatin by Other (see comment). Avoid or Use Alternate Drug. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• avanafil

  isoniazid will increase the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; significantly increased levels may result in significant adverse events including severe hypotension, syncope, visual changes, and priapism. Coadministration with strong CYP3A4 is contraindicated.

• avapritinib

  rifampin will decrease the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of avapritinib with moderate CYP3A4 inhibitors. If unable to avoid, reduce avapritinib starting dose. See drug monograph Dosage Modifications.

• axitinib

  rifampin decreases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Selection of concomitant medication with no or minimal CYP3A4 induction potential is recommended.
  
  isoniazid increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with strong CYP3A4 inhibitors, reduce axitinib dose by 50%.

• bazedoxifene/conjugated estrogens

  rifampin will decrease the level or effect of bazedoxifene/conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin decreases levels of bazedoxifene/conjugated estrogens by increasing metabolism. Avoid or Use Alternate Drug. A reduction in bazedoxifene exposure may be associated with an increase risk of endometrial hyperplasia.

• bedaquiline

  isoniazid will increase the level or effect of bedaquiline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of bedaquiline with strong CYP3A4 inhibitors for >14 consecutive days, unless the benefit of treatment outweighs the risk

• BCG vaccine live

  rifampin decreases levels of BCG vaccine live by pharmacodynamic antagonism. Contraindicated.

• bedaquiline

  rifampin will decrease the level or effect of bedaquiline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of bedaquiline with strong CYP3A4 inducers due to potential for decreased therapeutic effect

• berotralstat

  rifampin decreases levels of berotralstat by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• bosutinib

  isoniazid increases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors increases bosutinib plasma concentration ~5-fold.
  
  rifampin decreases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inducers decreased bosutinib plasma concentration by ~85%.

• brigatinib

  isoniazid will increase the level or effect of brigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use of a strong CYP3A inhibitor cannot be avoided, reduce the brigatinib once daily dose by about 50% (ie, from 180 mg to 90 mg, or from 90 mg to 60 mg). After discontinuation of a strong CYP3A inhibitor, resume the brigatinib dose that was tolerated prior to initiating the strong CYP3A inhibitor.
  
  rifampin will decrease the level or effect of brigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong CYP3A4 inducers may decrease brigatinib efficacy.

• budesonide

  rifampin will decrease the level or effect of budesonide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• cabazitaxel

  isoniazid will increase the level or effect of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of cabazitaxel with strong CYP3A4 inhibitors should be avoided.

• buspirone

  rifampin will decrease the level or effect of buspirone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• cabozantinib

  rifampin will decrease the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of cabozantinib with strong CYP3A4 inducers. If a strong CYP3A4 inducer is required, increase cabozantinib dose by 40 mg/day (Cometriq) or by 20 mg/day (Cabometyx). Resume previous dose 2-3 days after strong CYP3A4 inducer discontinued.
  
  isoniazid will increase the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of cabozantinib with strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor is required, decrease cabozantinib dose by 40 mg/day (Cometriq) or by 20 mg/day (Cabometyx). Resume previous dose 2-3 days after strong CYP3A4 inhibitor discontinued.

• capmatinib

  rifampin will decrease the level or effect of capmatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ceritinib

  isoniazid increases levels of ceritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid if possible; if concomitant use is unavoidable, reduce ceritinib dose by ~33%; after discontinuation of strong CYP3A inhibitor, resume at previous dose.

• carbamazepine

  rifampin will decrease the level or effect of carbamazepine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ceritinib

  rifampin decreases levels of ceritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• cilostazol

  rifampin will decrease the level or effect of cilostazol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid increases toxicity of cilostazol by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Decrease cilostazol dose by 50%; serum levels of 3,4-dehydrocilostazol (active metabolite) increased by strong CYP2C19 inhibitors.

• cinacalcet

  rifampin will decrease the level or effect of cinacalcet by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• clopidogrel

  isoniazid decreases effects of clopidogrel by decreasing metabolism. Avoid or Use Alternate Drug. Cytochrome P450 2C19 inhibitors decrease the conversion of clopidogrel to its active form.

• clopidogrel

  rifampin will increase the level or effect of clopidogrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP3A4 inducers may increase the metabolism of clopidogrel to its active metabolite. Monitor patients for potential increase in antiplatelet effects when CYP3A4 inducers are used in combination with clopidogrel

• clozapine

  rifampin will decrease the level or effect of clozapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• colchicine

  rifampin will decrease the level or effect of colchicine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• conivaptan

  rifampin will decrease the level or effect of conivaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• conjugated estrogens

  rifampin will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• conjugated estrogens, vaginal

  rifampin will decrease the level or effect of conjugated estrogens, vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• copanlisib

  isoniazid will increase the level or effect of copanlisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use with strong CYP3A inhibitors cannot be avoided, reduce copanlisib dose to 45 mg.
  
  rifampin will decrease the level or effect of copanlisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of copanlisib with strong CYP3A4 inducers.

• cortisone

  rifampin will decrease the level or effect of cortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dabrafenib

  isoniazid increases levels of dabrafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dabigatran

  rifampin will decrease the level or effect of dabigatran by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Avoid coadministration. P-gp inducers reduce systemic exposure of dabigatran

• dabrafenib

  rifampin decreases levels of dabrafenib by increasing metabolism. Avoid or Use Alternate Drug. Strong CYP2C8 inducers may decrease dabrafenib levels.
  
  rifampin decreases levels of dabrafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• daridorexant

  rifampin will decrease the level or effect of daridorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• darifenacin

  rifampin will decrease the level or effect of darifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• darolutamide

  rifampin will decrease the level or effect of darolutamide by Other (see comment). Avoid or Use Alternate Drug. Darolutamide is a P-gp and CYP3A4 substrate. Avoid coadminstration of darolutamide with combined P-gp and strong or moderate CYP3A4 inducers.

• darunavir

  rifampin will decrease the level or effect of darunavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• dasatinib

  rifampin will decrease the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• deflazacort

  rifampin will decrease the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of deflazacort with moderate or strong CYP3A4 inducers.

• desvenlafaxine

  isoniazid and desvenlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.

• dexamethasone

  rifampin will decrease the level or effect of dexamethasone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• diazepam

  rifampin will decrease the level or effect of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dihydroergotamine

  rifampin will decrease the level or effect of dihydroergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dihydroergotamine intranasal

  rifampin will decrease the level or effect of dihydroergotamine intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• diltiazem

  rifampin will decrease the level or effect of diltiazem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with diltiazem and strong CYP3A4 inducers However, if concomitant use is necessary, consider dosage adjustment and close monitoring of pharmacologic effects (eg, blood pressure) whenever a strong CYP3A4 inducer is added to or discontinued from therapy.

• dolutegravir

  rifampin will decrease the level or effect of dolutegravir by increasing metabolism. Avoid or Use Alternate Drug. Increase dolutegravir dose to 50 mg BID when coadministered with strong UGT1A/CYP3A inducers

• dronedarone

  rifampin will decrease the level or effect of dronedarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of dronedarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• duloxetine

  rifampin will decrease the level or effect of duloxetine by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated.

• elacestrant

  isoniazid will increase the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• duvelisib

  rifampin will decrease the level or effect of duvelisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with a strong CYP3A inducer decreases duvelisib area under the curve (AUC), which may reduce duvelisib efficacy.

• edoxaban

  rifampin will decrease the level or effect of edoxaban by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Avoid coadministration of edoxaban with potent P-gp inducers

• elacestrant

  rifampin will decrease the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• eletriptan

  rifampin will decrease the level or effect of eletriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• eliglustat

  rifampin will decrease the level or effect of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A inducers significantly decreases eliglustat exposure; coadministration not recommended

• eluxadoline

  rifampin increases levels of eluxadoline by decreasing metabolism. Avoid or Use Alternate Drug. Decrease eluxadoline dose to 75 mg PO BID if coadministered with OATP1B1 inhibitors. .

• elvitegravir

  rifampin will decrease the level or effect of elvitegravir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid; coadministration with CYP3A inducers may result in decreased plasma concentrations of elvitegravir and/or a concomitantly administered protease inhibitor and lead to loss of therapeutic effect and to possible resistance

• encorafenib

  isoniazid will increase the level or effect of encorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use of a strong CYP3A4 inhibitor is unavoidable, reduce encorafenib dose to one-third of the dose (eg, reduce from 450 mg/day to 150 mg/day). After discontinuing the inhibitor for 3-5 elimination half-lives, resume previous encorafenib dose.
  
  rifampin will decrease the level or effect of encorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• entrectinib

  isoniazid will increase the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of moderate CYP3A4 inhibitors with entrectinib, a CYP3A4 substrate. If coadministration unavoidable, reduce dose to 200 mg/day for patients aged 12 y or older with BSA >1.50m2. Resume previous entrectinib dose after discontinuing moderate CYP3A inhibitor for 3-5 elimination half-lives.
  
  rifampin will decrease the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• enzalutamide

  rifampin will decrease the level or effect of enzalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider using an alternant that has no or minimal CYP3A4 induction potential when possible. If unavoidable, increase enzalutamide dose from 160 mg qDay to 240 mg qDay. If a strong CYP3A4 inducer is discontinued, return enzalutamide dose to dose used before initiating the strong CY

• eplerenone

  isoniazid will increase the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erdafitinib

  erdafitinib will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If coadministration unavoidable, separate administration by at least 6 hr before or after administration of P-gp substrates with narrow therapeutic index.
  
  rifampin will decrease the level or effect of erdafitinib by altering metabolism. Avoid or Use Alternate Drug. Avoid coadministration of strong CYP2C9 or CYP3A4 inducers with erdafitinib.
  
  isoniazid will increase the level or effect of erdafitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with strong CYP3A4 inhibitors, monitor closely for adverse reactions and consider decreasing dose accordingly. If strong CYP3A4 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities.

• ergotamine

  rifampin will decrease the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erlotinib

  rifampin will decrease the level or effect of erlotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin base

  isoniazid will increase the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin base

  rifampin will decrease the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin ethylsuccinate

  isoniazid will increase the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin lactobionate

  rifampin will decrease the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin stearate

  rifampin will decrease the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• esomeprazole

  isoniazid will increase the level or effect of esomeprazole by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.

• estradiol

  rifampin will decrease the level or effect of estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• estrogens conjugated synthetic

  rifampin will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• estropipate

  rifampin will decrease the level or effect of estropipate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ethinylestradiol

  rifampin will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.

• etonogestrel

  rifampin will decrease the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• etravirine

  isoniazid will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• everolimus

  isoniazid will increase the level or effect of everolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of everolimus by P-glycoprotein (MDR1) efflux transporter. Contraindicated.
  
  rifampin will decrease the level or effect of everolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fedratinib

  isoniazid will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.
  
  rifampin will decrease the level or effect of fedratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Effect of coadministering a strong CYP3A4 inducer with fedratinib has not been studied.
  
  isoniazid will increase the level or effect of fedratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• felbamate

  rifampin will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fentanyl

  isoniazid will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• felodipine

  rifampin will decrease the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fentanyl intranasal

  isoniazid will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl transdermal

  isoniazid will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl transmucosal

  isoniazid will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fesoterodine

  rifampin will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fexinidazole

  rifampin will increase the level or effect of fexinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP450 inducers may significantly increase plasma concentrations of fexinidazole?s active metabolites: fexinidazole sulfoxide (M1) and fexinidazole sulfone (M2). M2 plasma concentrations associated with increased QT prolongation risks.
  
  isoniazid will decrease the level or effect of fexinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration, monitor fexinidazole for decreased efficacy owing to decreased plasma concentrations of active M1 and M2 metabolites.
  
  fexinidazole will decrease the level or effect of rifampin by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug. Coadministration may decrease plasma concentrations of CYP2B6 substrates owing to fexinidazole inducing CYP2B6.

• finerenone

  rifampin will decrease the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fluticasone intranasal

  isoniazid will increase the level or effect of fluticasone intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors may increase systemic corticosteroid adverse effects; monitor for signs/symptoms of high corticosteroid concentrations including Cushing type signs/symptoms.

• fludrocortisone

  rifampin will decrease the level or effect of fludrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fosamprenavir

  rifampin will decrease the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• fosaprepitant

  rifampin will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fostamatinib

  rifampin will decrease the level or effect of fostamatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• futibatinib

  rifampin will decrease the level or effect of futibatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of futibatinib with drugs that are dual P-gp and strong CYP3A inducers may decrease futibatinib efficacy.

• ganaxolone

  rifampin will decrease the level or effect of ganaxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ganaxolone with moderate or strong CYP3A4 inducers. If coadministration unavoidable, consider increasing ganaxolone dose; however, do not exceed maximum daily dose for weight.

• gilteritinib

  rifampin will decrease the level or effect of gilteritinib by Other (see comment). Avoid or Use Alternate Drug. Gilteritinib is a P-gp and CYP3A4 substrates. Coadministration of gilteritinib with a combined P-gp and strong CYP3A inducer decreases gilteritinib exposure and efficacy.
  
  isoniazid will increase the level or effect of gilteritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternatives to any strong CYP3A4 inhibitor when coadministered with gilteritinib. If such a combination cannot be avoided, closely monitor for gilteritinib-related adverse effects. Interrupt and reduce gilteritinib dosage in patients with serious or life-threatening toxicity.

• glasdegib

  rifampin will decrease the level or effect of glasdegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of glasdegib with strong CYP3A inducers.
  
  isoniazid will increase the level or effect of glasdegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternate therapies that are not strong CYP3A inhibitors or monitor for increased risk of adverse effects, including QTc interval prolongation.

• glecaprevir/pibrentasvir

  rifampin will decrease the level or effect of glecaprevir/pibrentasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• ibrutinib

  isoniazid increases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of ibrutinib and strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor must be used short-term (eg, anti-infectives for =7 days), interrupt ibrutinib therapy until strong CYP3A4 inhibitor is discontinued.

• hydrocortisone

  rifampin will decrease the level or effect of hydrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• hydroxyprogesterone caproate (DSC)

  rifampin will decrease the level or effect of hydroxyprogesterone caproate (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ibrutinib

  rifampin decreases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A inducers decrease ibrutinib plasma concentrations by ~10-fold.

• idelalisib

  rifampin will decrease the level or effect of idelalisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration; strong CYP3A4 inducers significantly decrease idelalisib systemic exposure
  
  isoniazid will increase the level or effect of idelalisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministered with strong CYP3A inhibitors, monitor for signs of idelalisib toxicity; follow recommendations for dosage modifications if adverse reactions occur

• iloperidone

  rifampin will decrease the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• irinotecan

  isoniazid will increase the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• indinavir

  rifampin will decrease the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin decreases levels of indinavir by increasing metabolism. Contraindicated.

• infigratinib

  rifampin will decrease the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• irinotecan

  rifampin will decrease the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• irinotecan liposomal

  isoniazid will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• isocarboxazid

  isocarboxazid and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug.

• isoniazid

  rifampin increases toxicity of isoniazid by increasing metabolism. Avoid or Use Alternate Drug. Rifampin enhances the metabolism of isoniazid to hepatotoxic metabolites.

• istradefylline

  rifampin will decrease the level or effect of istradefylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of istradefylline with strong CYP3A4 inducers.

• ivabradine

  rifampin will decrease the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ivabradine with moderate CYP3A4 inducers.

• ivacaftor

  rifampin decreases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with strong CYP3A4 inducers; systemic exposure of ivacaftor substantially reduced (ie, ~9-fold).

• ivosidenib

  rifampin will decrease the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of ivosidenib with strong CYP3A4 inducers decreased ivosidenib plasma concentrations.

• ixabepilone

  rifampin will decrease the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ixazomib

  rifampin will decrease the level or effect of ixazomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ixazomib with strong CYP3A inducers. Strong inducers have been shown to decrease ixazomib Cmax by 54% and AUC by 74%.

• lansoprazole

  rifampin will decrease the level or effect of lansoprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lapatinib

  rifampin will decrease the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• larotrectinib

  rifampin will decrease the level or effect of larotrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of larotrectinib with strong CYP3A4 inducers is unavoidable, double larotrectinib dose. Resume prior larotrectinib dose once CYP3A4 inducer discontinued for 3-5 half-lives

• lasmiditan

  lasmiditan increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• lefamulin

  isoniazid will increase the level or effect of lefamulin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lefamulin with strong CYP3A inhibitors.
  
  rifampin will decrease the level or effect of lefamulin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lefamulin with strong or moderate CYP3A inducers unless the benefit outweighs risks. Monitor for reduced efficacy.

• lemborexant

  isoniazid will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lemborexant with moderate or strong CYP3A inhibitors.
  
  rifampin will decrease the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• leniolisib

  rifampin will decrease the level or effect of leniolisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• linezolid

  linezolid and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug. Linezolid may increase serotonin as a result of MAO-A inhibition. If linezolid must be administered, discontinue serotonergic drug immediately and monitor for CNS toxicity. Serotonergic therapy may be resumed 24 hours after last linezolid dose or after 2 weeks of monitoring, whichever comes first.

• letermovir

  rifampin will decrease the level or effect of letermovir by Other (see comment). Avoid or Use Alternate Drug. Coadministration of letermovir with UCT1A1/3 inducers is not recommended.
  
  rifampin will decrease the level or effect of letermovir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Coadministration of letermovir with P-gp inducers is not recommended.

• lomitapide

  rifampin will decrease the level or effect of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lopinavir

  rifampin will decrease the level or effect of lopinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• loratadine

  rifampin will decrease the level or effect of loratadine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lorcaserin

  isoniazid and lorcaserin both increase serotonin levels. Avoid or Use Alternate Drug.

• lorlatinib

  isoniazid will increase the level or effect of lorlatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministering lorlatinib with strong CYP3A inhibitors. If unavoidable, reduce lorlatinib dose by 25 mg/day. If strong CYP3A inhibitor discontinued, increase to previous lorlatinib (dose after 3 plasma half-lives of strong CYP3A inhibitor). See monograph for further details.

• lovastatin

  rifampin will decrease the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lumateperone

  rifampin will decrease the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lurbinectedin

  isoniazid will increase the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• macimorelin

  rifampin will decrease the level or effect of macimorelin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Potential for false positive test results if macimorelin and strong CYP3A4 inducers are coadministered. Discontinue strong CYP3A4 inducer, allowing for sufficient washout time, before testing.

• macitentan

  isoniazid will increase the level or effect of macitentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministering macitentan with strong CYP3A4 inhibitors

• macitentan

  rifampin will decrease the level or effect of macitentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministering macitentan with strong CYP3A4 inducers

• maraviroc

  rifampin will decrease the level or effect of maraviroc by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• mestranol

  rifampin will decrease the level or effect of mestranol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin decreases levels of mestranol by increasing metabolism. Avoid or Use Alternate Drug. May result in contraceptive failure.

• methadone

  rifampin will decrease the level or effect of methadone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• methylene blue

  methylene blue and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug. Methylene blue and isoniazid may increase serotonin as a result of MAO-A inhibition. If methylene blue must be administered, discontinue isoniazid immediately and monitor for CNS toxicity. Isoniazid may be resumed 24 hours after last methylene blue dose or after 2 weeks of monitoring, whichever comes first.

• methylprednisolone

  rifampin will decrease the level or effect of methylprednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• midazolam

  rifampin will decrease the level or effect of midazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• midazolam intranasal

  isoniazid will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of moderate CYP3A4 inhibitors with midazolam intranasal causes higher midazolam systemic exposure, which may prolong sedation.

• midostaurin

  rifampin will decrease the level or effect of midostaurin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inducers may decrease midostaurin concentrations resulting in reduced efficacy.
  
  isoniazid will increase the level or effect of midostaurin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong CYP3A4 inhibitors cannot be avoided, monitor midostaurin for increased risk of adverse reactions, especially during the first week of treatment.

• mirtazapine

  isoniazid will increase the level or effect of mirtazapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• naldemedine

  rifampin will decrease the level or effect of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with strong CYP3A4 inducers.

• mobocertinib

  isoniazid will increase the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use of moderate CYP3A4 inhibitor unavoidable, reduce mobocertinib dose by ~50% (eg, 160 to 80 mg); closely monitor QTc interval.

• neratinib

  rifampin will decrease the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inducers.
  
  isoniazid will increase the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inhibitors.

• netupitant/palonosetron

  rifampin will decrease the level or effect of netupitant/palonosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Netupitant is mainly metabolized by CYP3A4; avoid use in patients who are chronically using a strong CYP3A4 inducer

• nilotinib

  isoniazid will increase the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• nevirapine

  rifampin will decrease the level or effect of nevirapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• nicardipine

  rifampin will decrease the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• nilotinib

  rifampin will decrease the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• nintedanib

  rifampin decreases levels of nintedanib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Avoid coadministration, particularly for P-gp inducers that are also CYP3A4 inducers; nintedanib is a substrate of P-gp and to a less extent CYP3A4.

• nisoldipine

  rifampin will decrease the level or effect of nisoldipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of nisoldipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• norethindrone

  rifampin decreases levels of norethindrone by increasing metabolism. Avoid or Use Alternate Drug. Avoid coadministration unless benefit outweighs risk. When coadministered, hormonal contraceptives are not a reliable method of effective birth control. Concomitant use may increase incidence of menstruation associated adverse effects (amenorrhea, dysmenorrhea, menorrhagia).
  
  rifampin will decrease the level or effect of norethindrone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use of nonhormonal contraceptives advised

• olaparib

  isoniazid will increase the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong CYP3A inhibitors cannot be avoided, reduce olaparib dose to 150 mg (capsule) or 100 mg (tablet) PO BID. Do not substitute tablets with capsules.

• norethindrone acetate

  rifampin decreases levels of norethindrone acetate by increasing metabolism. Avoid or Use Alternate Drug. Avoid coadministration unless benefit outweighs risk. When coadministered, hormonal contraceptives are not a reliable method of effective birth control. Concomitant use may increase incidence of menstruation associated adverse effects (amenorrhea, dysmenorrhea, menorrhagia).

• norethindrone transdermal

  rifampin will decrease the level or effect of norethindrone transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration unless benefit outweighs risk. When coadministered, hormonal contraceptives are not a reliable method of effective birth control. Concomitant use may increase incidence of menstruation associated adverse effects (amenorrhea, dysmenorrhea, menorrhagia).

• olaparib

  rifampin will decrease the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of olaparib with strong CYP3A4 inducers.

• olutasidenib

  rifampin will decrease the level or effect of olutasidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong or moderate CYP3A inducers decrease olutasidenib (a CYP3A4 substrate) plasma concentrations and efficacy.

• omaveloxolone

  isoniazid will increase the level or effect of omaveloxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unavoidable, reduce omaveloxolone dose to 100 mg/day. Closely monitor for adverse effects. If adverse effects emerge, further reduce to 50 mg/day.
  
  rifampin will decrease the level or effect of omaveloxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• omeprazole

  rifampin will decrease the level or effect of omeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of omeprazole by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.

• osimertinib

  isoniazid will increase the level or effect of osimertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of osimertinib with strong CYP3A4 inhibitors. If no other alternative treatment exists, monitor patient more closely for adverse effects.
  
  rifampin will decrease the level or effect of osimertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of osimertinib with strong CYP3A inducers.

• oxycodone

  isoniazid increases levels of oxycodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Oxycodone dose reduction may be warranted when coadministered with strong CYP3A4 inhibitors.

• ozanimod

  rifampin will decrease the level or effect of ozanimod by Other (see comment). Avoid or Use Alternate Drug. Coadministration of ozanimod (a CYP2C8 substrate) with strong CYP2C8 inducers decreases the exposure of the active metabolites (CC112273 and CC1084037) of ozanimod, which may decrease the effiicacy of ozanimod. Therefore, coadministration of ozanimod with strong CYP2C8 inducers is not recommended.

• pacritinib

  isoniazid will decrease the level or effect of pacritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• palbociclib

  isoniazid will increase the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of palbociclib with strong CYP3A inhibitors. If unable to avoid, reduce palbociclib dose to 75 mg/day.
  
  rifampin will decrease the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A inducers decrease palbociclib plasma exposure by ~85%.

• pazopanib

  rifampin will decrease the level or effect of pazopanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• pemigatinib

  isoniazid will increase the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pemigatinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pemigatinib dose.

• pemigatinib

  rifampin will decrease the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• perampanel

  rifampin will decrease the level or effect of perampanel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Increased perampanel dose may be needed when coadministered

• pexidartinib

  rifampin and pexidartinib both increase inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.
  
  rifampin will increase the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pexidartinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pexidartinib dose.
  
  isoniazid and pexidartinib both increase inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.
  
  isoniazid will increase the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pexidartinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pexidartinib dose.

• phenelzine

  phenelzine and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug.

• pitavastatin

  rifampin increases toxicity of pitavastatin by Other (see comment). Avoid or Use Alternate Drug. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• pimavanserin

  isoniazid will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease dose to 17 mg/day if pimavanserin is coadministered with strong CYP3A4 inhibitors.

• pimozide

  isoniazid increases levels of pimozide by decreasing metabolism. Contraindicated. Risk of QT interval prolongation.

• pomalidomide

  rifampin decreases levels of pomalidomide by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid increases levels of pomalidomide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin decreases levels of pomalidomide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin decreases levels of pomalidomide by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• ponatinib

  rifampin decreases levels of ponatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid unless the coadministration outweighs the possible risk of ponatinib underexposure; monitor for signs of reduced efficacy.
  
  isoniazid increases levels of ponatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease ponatinib starting dose to 30 mg qDay if coadministration with strong CYP3A4 inhibitors cannot be avoided.

• ponesimod

  rifampin will decrease the level or effect of ponesimod by Other (see comment). Avoid or Use Alternate Drug. Not recommended. Based on limited data, coadministration of strong CYP3A4 and UGT1A1 inducers (eg, rifampin, phenytoin, carbamazepine) may decrease systemic exposure of ponesimod. The clinical relevance is unclear.

• pralsetinib

  isoniazid will increase the level or effect of pralsetinib by affecting hepatic enzyme CYP2E1 metabolism. Avoid or Use Alternate Drug.

• pralsetinib

  rifampin will decrease the level or effect of pralsetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid, double current pralsetinib dose starting on Day 7 of coadministration with strong CYP3A inducer. After inducer has been discontinued for at least 14 days, resume previous pralsetinib dose.

• prednisolone

  rifampin will decrease the level or effect of prednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• prednisone

  rifampin will decrease the level or effect of prednisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• pretomanid

  rifampin, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.
  
  isoniazid, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.
  
  rifampin will decrease the level or effect of pretomanid by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP3A4 substrate. Avoid coadministration of strong or moderate CYP3A4 inducers.

• primaquine

  rifampin will decrease the level or effect of primaquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ranolazine

  isoniazid will increase the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• progesterone intravaginal gel

  rifampin will decrease the level or effect of progesterone intravaginal gel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use of nonhormonal contraceptives advised

• progesterone micronized

  rifampin will decrease the level or effect of progesterone micronized by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use of nonhormonal contraceptives advised

• progesterone, natural

  rifampin will decrease the level or effect of progesterone, natural by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use of nonhormonal contraceptives advised

• propofol

  rifampin will decrease the level or effect of propofol by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug.

• pyrazinamide

  rifampin, pyrazinamide. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive hepatotoxicity.

• quazepam

  rifampin will decrease the level or effect of quazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• quetiapine

  rifampin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• quinidine

  rifampin will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ranolazine

  rifampin will decrease the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• red yeast rice

  isoniazid will increase the level or effect of red yeast rice by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. May increase creatine kinase levels and increase risk of myopathy or rhabdomyolysis; red yeast rice contains monocolin K (reportedly identical to lovastatin)

• repaglinide

  rifampin will decrease the level or effect of repaglinide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• revefenacin

  rifampin increases levels of revefenacin by Other (see comment). Avoid or Use Alternate Drug. Comment: OATP1B1 and OATP1B3 transport inhibitors may increase systemic exposure of revefenacin's active metabolite. Coadministration not recommended.

• ribociclib

  rifampin will decrease the level or effect of ribociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of ribociclib with strong CYP3A inducers should be avoided.

• rifabutin

  rifampin will decrease the level or effect of rifabutin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• rifampin

  rifampin increases toxicity of isoniazid by increasing metabolism. Avoid or Use Alternate Drug. Rifampin enhances the metabolism of isoniazid to hepatotoxic metabolites.

• rimegepant

  rifampin will decrease the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• riociguat

  isoniazid will increase the level or effect of riociguat by Other (see comment). Avoid or Use Alternate Drug. Coadministration of riociguat (an ABCG2 [BCRP] substrate) with strong ABCG2 inhibitors may require a decreased initial dose of 0.5 mg PO TID; monitor for signs of hypotension and reduce dose if needed

• ripretinib

  rifampin will decrease the level or effect of ripretinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with a strong CYP3A inhibitor will decrease systemic exposure to ripretinib and its active metabolite (DP-5439), which may decrease risk of adverse reactions.

• ritonavir

  rifampin will decrease the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• rolapitant

  rifampin will decrease the level or effect of rolapitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Long-term coadministration of strong CYP3A4 inducers with rolapitant may significantly decrease rolapitant efficacy.

• romidepsin

  rifampin will decrease the level or effect of romidepsin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong 3A4 inducers should be avoided if possible.

• ruxolitinib

  isoniazid will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce ruxolitinib starting dose to 10 mg BID with platelet count 100 X 10^9/L or more and concurrent use of strong CYP3A4 inhibitors; avoid with platelet counts <100 X 10^9/L

• ruxolitinib topical

  isoniazid will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce ruxolitinib starting dose to 10 mg BID with platelet count 100 X 10^9/L or more and concurrent use of strong CYP3A4 inhibitors; avoid with platelet counts <100 X 10^9/L

• selpercatinib

  rifampin will decrease the level or effect of selpercatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• selumetinib

  isoniazid will increase the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors cannot be avoided, reduce selumetinib dosage (refer to selumetinib monograph for further information). After discontinuation of the strong or moderate CYP3A4 inhibitor for 3 elimination half-lives, resume selumetinib dose that was taken before initiating the inhibitor.
  
  rifampin will decrease the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• silodosin

  rifampin will decrease the level or effect of silodosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of silodosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• simvastatin

  rifampin will decrease the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• siponimod

  rifampin will decrease the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a drug that causes moderate CYP2C9 plus a moderate or strong CYP3A4 inducer is not recommended. Coadministration with moderate or strong CYP3A4 inducers alone is not recommended for patients with CYP2C9*1/*3 and*2/*3 genotype.
  
  isoniazid will increase the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a moderate or strong CYP3A4 inhibitor PLUS a moderate or strong CYP2C9 inhibitor is not recommended.

• sirolimus

  rifampin will decrease the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sofosbuvir

  rifampin will decrease the level or effect of sofosbuvir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. P-gp inducers decrease sofosbuvir levels, and therefore decrease conversion to sofosbuvir's active metabolite (GS-331007) responsible for 90% of pharmacologic effect

• sonidegib

  isoniazid will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sonidegib with strong CYP3A4 inhibitors.

• sofosbuvir/velpatasvir

  rifampin will decrease the level or effect of sofosbuvir/velpatasvir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Sofosbuvir and velpatasvir are substrates of the drug transporter P-gp. Potent P-gp inducers may significantly decrease sofosbuvir and velpatasvir plasma concentrations, leading to potentially reduced therapeutic effect.
  
  rifampin will decrease the level or effect of sofosbuvir/velpatasvir by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug. Velpatasvir is a substrate of CYP2B6, CYP2C8, and CYP3A4. Drugs that are moderate-to-potent inducers of CYP2B6, CYP2C8, or CYP3A4 may significantly decrease velpatasvir plasma concentrations, leading to potentially reduced therapeutic effect.
  
  rifampin will decrease the level or effect of sofosbuvir/velpatasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Velpatasvir is a substrate of CYP2B6, CYP2C8, and CYP3A4. Drugs that are moderate-to-potent inducers of CYP2B6, CYP2C8, or CYP3A4 may significantly decrease velpatasvir plasma concentrations, leading to potentially reduced therapeutic effect.

• solifenacin

  rifampin will decrease the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sonidegib

  rifampin will decrease the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sonidegib with strong or moderate CYP3A4 inducers.

• sorafenib

  rifampin decreases levels of sorafenib by increasing metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of sorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sotorasib

  rifampin will decrease the level or effect of sotorasib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  sotorasib will decrease the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If use is unavoidable, refer to the prescribing information of the P-gp substrate for dosage modifications.

• sparsentan

  rifampin will decrease the level or effect of sparsentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• stiripentol

  rifampin will decrease the level or effect of stiripentol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration of stiripentol with strong CYP3A4 inducers, increase stiripentol dose.
  
  rifampin will decrease the level or effect of stiripentol by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration of stiripentol with strong CYP1A2 inducers, increase stiripentol dose.
  
  rifampin will decrease the level or effect of stiripentol by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration of stiripentol with strong CYP1A2 inducers, increase stiripentol dose.

• sulbactam/durlobactam

  rifampin will increase the level or effect of sulbactam/durlobactam by Other (see comment). Avoid or Use Alternate Drug. Sulbactam is predicted to have active secretion by OATP1 as a significant portion of total clearance; therefore, inhibition of OAT1 may increase sulbactam plasma concentrations

• sunitinib

  rifampin will decrease the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• suvorexant

  isoniazid increases levels of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Suvorexant not recommended with use of strong CYP3A4 inhibitors.

• tacrolimus

  rifampin will decrease the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tamsulosin

  rifampin will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tazemetostat

  rifampin will decrease the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of tazemetostat with moderate CYP3A4 inhibitors. If coadministration is unavoidable, reduce tazemetostat current dose (see drug monograph Dosage Modifications).

• temsirolimus

  rifampin will decrease the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tizanidine

  isoniazid will increase the level or effect of tizanidine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.

• tepotinib

  tepotinib will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If concomitant use unavoidable, reduce the P-gp substrate dosage if recommended in its approved product labeling.

• tezacaftor

  rifampin will decrease the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• theophylline

  rifampin will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tivozanib

  rifampin will decrease the level or effect of tivozanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tizanidine

  rifampin will decrease the level or effect of tizanidine by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated.

• tofacitinib

  isoniazid increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce tofacitinib dose to 5 mg qDay when coadministered with potent CYP3A4 inhibitors.

• tolterodine

  rifampin will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tolvaptan

  isoniazid will increase the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• trabectedin

  isoniazid will increase the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If strong CYP3A inhibitor must be used, short-term (eg, less than 14 days), administer strong CYP3A inhibitor 1 week after trabectedin infusion, and discontinue the day prior to next trabectedin infusion
  
  rifampin will decrease the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tranylcypromine

  tranylcypromine and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug.

• trazodone

  rifampin will decrease the level or effect of trazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• triamcinolone acetonide injectable suspension

  rifampin will decrease the level or effect of triamcinolone acetonide injectable suspension by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• triazolam

  rifampin will decrease the level or effect of triazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• trofinetide

  trofinetide will increase the level or effect of rifampin by Other (see comment). Avoid or Use Alternate Drug. Trofinetide (an OATP131 and OATP13B inhibitor) may increase plasma levels of OATP131 or OATP13B substrates. Avoid coadministration with sensitive substrates.

• tucatinib

  rifampin will decrease the level or effect of tucatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of tucatinib by Other (see comment). Avoid or Use Alternate Drug. Coadministration of tucatinib (a CYP2C8 substrate) with a strong or moderate CYP2C8 inducer decreases tucatinib plasma concentrations.

• typhoid vaccine live

  rifampin decreases levels of typhoid vaccine live by pharmacodynamic antagonism. Contraindicated.

• ubrogepant

  rifampin will decrease the level or effect of ubrogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ulipristal

  rifampin will decrease the level or effect of ulipristal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• upadacitinib

  rifampin will decrease the level or effect of upadacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid upadacitinib coadministration with strong CYP3A4 inducers.

• valbenazine

  rifampin will decrease the level or effect of valbenazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Concomitant use not recommended.

• vardenafil

  rifampin will decrease the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• velpatasvir

  rifampin will decrease the level or effect of velpatasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• vemurafenib

  rifampin decreases levels of vemurafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid increases levels of vemurafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• venetoclax

  rifampin will decrease the level or effect of venetoclax by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of venetoclax with strong or moderate CYP3A inducers. Consider alternative treatment with agents that have less CYP3A induction.

• vilazodone

  isoniazid, vilazodone. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug. Concomitant therapy should be discontinued immediately if signs or symptoms of serotonin syndrome emerge and supportive symptomatic treatment should be initiated. .
  
  isoniazid increases levels of vilazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors may increase vilazodone plasma levels by 50% - Reduce daily dose to 20 mg.

• verapamil

  rifampin will decrease the level or effect of verapamil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• vonoprazan

  rifampin will decrease the level or effect of vonoprazan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• vorapaxar

  rifampin decreases levels of vorapaxar by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid increases levels of vorapaxar by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• voriconazole

  rifampin will decrease the level or effect of voriconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• voxelotor

  rifampin will decrease the level or effect of voxelotor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor is primarily metabolized by CYP3A4. Avoid coadministration with moderate or strong CYP3A4 inducers. If unable to avoid coadministration, increase voxelotor dose (see Dosage Modifications).

• voxilaprevir

  rifampin will decrease the level or effect of voxilaprevir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid use of voxilaprevir and rifampin. Rifampin is listed as contraindicated when coadministered with sofosbuvir/velpatasvir/voxilaprevir in the prescribing information.

• zanubrutinib

  rifampin will decrease the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• zavegepant intranasal

  rifampin will increase the level or effect of zavegepant intranasal by Other (see comment). Avoid or Use Alternate Drug. OATP1B3 inhibitors may result in a significant increase in systemic exposure of zavegepant (an OATP1B3 substrate).

Monitor Closely (456)

• 5-HTP

  5-HTP and isoniazid both increase serotonin levels. Use Caution/Monitor.

• abemaciclib

  isoniazid will increase the level or effect of abemaciclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A4 inhibitors increase plasma levels of abemaciclib and its metabolites. Abemaciclib dose reduction required. If a strong CYP3A4 inhibitor is discontinued, increase abemaciclib to the dose prior to initiating the strong inhibitor.

• abiraterone

  rifampin decreases levels of abiraterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid coadministration of abiraterone with strong CYP3A4 inducers; if a strong CYP3A4 inducer must be used, increase abiraterone dosage frequency from once daily to twice daily.

• abrocitinib

  isoniazid will increase the level or effect of abrocitinib by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Start abrocitinib 50 mg qDay when coadministered with CYP2C19 inhibitors. If adequate response not achieved after 12 weeks, may increase to 100 mg qDay. Discontinue if inadequate response after dosage increase.

• acetaminophen

  isoniazid will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.

• acetaminophen IV

  isoniazid will increase the level or effect of acetaminophen IV by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.

• acetaminophen rectal

  isoniazid will increase the level or effect of acetaminophen rectal by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.

• alfentanil

  rifampin will decrease the level or effect of alfentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• alfuzosin

  rifampin will decrease the level or effect of alfuzosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• almotriptan

  isoniazid will increase the level or effect of almotriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  almotriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.

• alosetron

  rifampin will decrease the level or effect of alosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of alosetron by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of alosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of alosetron by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• alprazolam

  isoniazid will increase the level or effect of alprazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• aluminum hydroxide

  aluminum hydroxide will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids

• aluminum hydroxide

  aluminum hydroxide decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• aluminum hydroxide/magnesium carbonate

  aluminum hydroxide/magnesium carbonate will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids

• aluminum hydroxide/magnesium trisilicate

  aluminum hydroxide/magnesium trisilicate will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids

• ambrisentan

  rifampin will decrease the level or effect of ambrisentan by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of ambrisentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration was associated with a transient 2-fold increase in ambrisentan AUC; however, by day 7, rifampin had no clinically important effect on ambrisentan. Use with caution.

• amifampridine

  isoniazid increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.

• amikacin

  rifampin will decrease the level or effect of amikacin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• amiodarone

  isoniazid will increase the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• amitriptyline

  isoniazid will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  amitriptyline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  rifampin will decrease the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• amlodipine

  rifampin will decrease the level or effect of amlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• amoxapine

  amoxapine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• amobarbital

  rifampin decreases levels of amobarbital by increasing metabolism. Use Caution/Monitor.

• antipyrine

  rifampin will decrease the level or effect of antipyrine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• apalutamide

  apalutamide will decrease the level or effect of rifampin by increasing elimination. Use Caution/Monitor. Apalutamide weakly induces OATP1B1 and may decrease systemic exposure of drugs that are OATP1B1 substrates.
  
  isoniazid will increase the level or effect of apalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of apalutamide with strong CYP3A4 or CYP2C8 inhibitors does not require initial dosage modification; however, dose reduction may be needed based on tolerability.

• aprepitant

  isoniazid will increase the level or effect of aprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• armodafinil

  rifampin will decrease the level or effect of armodafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of armodafinil by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• aripiprazole

  isoniazid will increase the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• armodafinil

  isoniazid will increase the level or effect of armodafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• artemether/lumefantrine

  isoniazid will increase the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• artesunate

  rifampin will decrease the level or effect of artesunate by increasing metabolism. Use Caution/Monitor. Coadministration may decrease AUC and peak plasma concentration of active artesunate metabolite (DHA) by inducing UGT. Monitor for decreased efficacy.

• asenapine

  rifampin will decrease the level or effect of asenapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• atazanavir

  isoniazid will increase the level or effect of atazanavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• atogepant

  isoniazid will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Recommended atogepant dosage is 10 mg PO qDay when coadministered with strong CYP3A4 inhibitors.
  
  rifampin will increase the level or effect of atogepant by Other (see comment). Modify Therapy/Monitor Closely. Recommended dosage of atogepant (an OATP1B1 substrate) with concomitant use of OATP inhibitors is 10 mg or 30 mg qDay.
  
  rifampin will decrease the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Recommended atogepant dosage with concomitant use of strong or moderate CYP3A4 inducers is 30 mg or 60 mg qDay.

• atorvastatin

  isoniazid will increase the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of atorvastatin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• atovaquone

  rifampin decreases levels of atovaquone by increasing metabolism. Use Caution/Monitor.

• belzutifan

  isoniazid will increase the level or effect of belzutifan by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Belzutifan is a CYP2C19 substrate. Coadministration with CYP2C19 inhibitors may increase incidence or severity of adverse effects. Monitor for anemia and hypoxia and reduce belzutifan dose as recommended.

• avanafil

  rifampin will decrease the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. For patients with ED, monitor response carefully because of potential for decreased effectiveness.

• avatrombopag

  rifampin will decrease the level or effect of avatrombopag by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. When treating ITP, coadministration of avatrombopag with a moderate or strong dual CYP2C9/3A4 inducer requires an increased avatrombopag starting dose. Refer to drug monograph for specific recommendations.

• azithromycin

  azithromycin will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• bazedoxifene/conjugated estrogens

  rifampin will decrease the level or effect of bazedoxifene/conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• belumosudil

  rifampin will decrease the level or effect of belumosudil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase belumosudil dosage to 200 mg PO BID when coadministered with strong CYP3A inducers.

• bendamustine

  rifampin decreases levels of bendamustine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Concentrations of active metabolites may be increased.

• benzhydrocodone/acetaminophen

  isoniazid will increase the level or effect of benzhydrocodone/acetaminophen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with strong CYP3A4 inhibitors may increase hydrocodone (benzhydrocodone is prodrug of hydrocodone) plasma concentrations and can result in potentially fatal respiratory depression.
  
  rifampin will decrease the level or effect of benzhydrocodone/acetaminophen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Caution when discontinuing CYP3A4 inducers that are coadministered with benzhydrocodone (prodrug of hydrocodone); plasma concentrations of hydrocodone may increase and can result in potentially fatal respiratory depression.

• berotralstat

  berotralstat will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor or titrate P-gp substrate dose if coadministered.

• bexarotene

  isoniazid will increase the level or effect of bexarotene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• bexagliflozin

  rifampin will decrease the level or effect of bexagliflozin by Other (see comment). Modify Therapy/Monitor Closely. Bexagliflozin is a major substrate of UGT1A9. If coadministered with a UGT1A9 inducer, consider adding another antihyperglycemic agent in patients requiring additional glycemic control.

• bexarotene

  rifampin will decrease the level or effect of bexarotene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• bortezomib

  rifampin will decrease the level or effect of bortezomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of bortezomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• bosentan

  rifampin will decrease the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of bosentan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• bosutinib

  bosutinib increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• brentuximab vedotin

  isoniazid increases levels of brentuximab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor patients for adverse reactions. .

• brentuximab vedotin

  rifampin decreases levels of brentuximab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• brexpiprazole

  isoniazid will increase the level or effect of brexpiprazole by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Administer a quarter of brexpiprazole dose if coadministered with a moderate CYP2D6 inhibitor PLUS a strong/moderate CYP3A4 inhibitor.
  
  rifampin will decrease the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Double brexpiprazole dose over 1-2 weeks if administered with a strong CYP3A4 inducer.
  
  isoniazid will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Administer half of the usual brexpiprazole dose when coadministered with strong CYP3A4 inhibitors. If also administered with a strong/moderate CYP2D6 inhibitor, administer a quarter of brexpiprazole dose.

• brivaracetam

  rifampin will decrease the level or effect of brivaracetam by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. The dose of brivaracetam should be increased up to 100% (ie, double the dosage) in patients while receiving concomitant treatment with rifampin.

• budesonide

  isoniazid will increase the level or effect of budesonide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• bromocriptine

  rifampin will decrease the level or effect of bromocriptine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• budesonide

  rifampin will decrease the level or effect of budesonide by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• buprenorphine

  rifampin will decrease the level or effect of buprenorphine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• buprenorphine buccal

  rifampin will decrease the level or effect of buprenorphine buccal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• buprenorphine subdermal implant

  rifampin will decrease the level or effect of buprenorphine subdermal implant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor patients already on buprenorphine subdermal implant who require newly-initiated treatment with CYP3A4 inducer for signs and symptoms of withdrawal. If the dose of the concomitant CYP3A4 inducer cannot be reduced or discontinued, implant removal may be necessary and the patient should then be treated with a buprenorphine dosage form that permits dose adjustments. If a CYP3A4 inducer is discontinued in a patient who has been stabilized on buprenorphine, monitor the patient for overmedication.
  
  isoniazid will increase the level or effect of buprenorphine subdermal implant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor patients already on buprenorphine subdermal implant who require newly-initiated treatment with CYP3A4 inhibitors for signs and symptoms of overmedication. If the dose of the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, implant removal may be necessary and the patient should then be treated with a buprenorphine dosage form that permits dose adjustments. If a CYP3A4 inhibitor is discontinued in a patient who has been stabilized on buprenorphine, monitor the patient for withdrawal.

• buprenorphine transdermal

  rifampin will decrease the level or effect of buprenorphine transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If coadministration is necessary, consider increasing buprenorphine transdermal dosage until stable. Monitor for signs of opioid withdrawal. If CYP3A4 inducer is discontinued, consider reducing the buprenorphine dosage and monitor for signs of respiratory depression.

• buprenorphine, long-acting injection

  isoniazid will increase the level or effect of buprenorphine, long-acting injection by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inhibitors should be monitored to ensure buprenorphine plasma levels are adequate. Within 2 weeks, if signs and symptoms of buprenorphine toxicity or overdose occur and the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.

• buprenorphine, long-acting injection

  rifampin will decrease the level or effect of buprenorphine, long-acting injection by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inducers should be monitored to ensure buprenorphine plasma levels are adequate. If the buprenorphine dose is inadequate and the CYP3A4 inducer cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.

• bupropion

  rifampin will decrease the level or effect of bupropion by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.

• buspirone

  isoniazid will increase the level or effect of buspirone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  buspirone and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• butabarbital

  rifampin decreases levels of butabarbital by increasing metabolism. Use Caution/Monitor.

• butalbital

  rifampin decreases levels of butalbital by increasing metabolism. Use Caution/Monitor.

• cabazitaxel

  rifampin will decrease the level or effect of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of strong CYP3A4 inducers may decrease cabazitaxel concentrations. Avoid coadministration.

• calcifediol

  rifampin, calcifediol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Drugs that stimulate microsomal hydroxylation reduce the half-life of calcifediol.
  
  isoniazid, calcifediol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. CYP450 inhibitors may inhibit enzymes involved in vitamin D metabolism (CYP24A1 and CYP27B1). This may alter serum levels of calcifediol and decrease the conversion of calcifediol to calcitriol. Dose adjustment of calcifediol may be required, and serum 25­hydroxyvitamin D, intact PTH, and serum calcium concentrations should be closely monitored when initiating or discontinuing a strong CYP3A4 inhibitor.

• calcitriol

  rifampin will decrease the level or effect of calcitriol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• calcium carbonate

  calcium carbonate decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• calcium carbonate

  calcium carbonate will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids

• calcium/vitamin D

  calcium/vitamin D will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids

• canagliflozin

  rifampin decreases levels of canagliflozin by increasing metabolism. Use Caution/Monitor. Coadministration with potent UGT enzyme inducers: Consider increasing dose to 300 mg qDay if 100 mg/day tolerate and additional glycemic control required (eGFR must be >60 mL/min/1.73 m2 to increase dose); if eGFR <60 mL/min/1.73 m2, consider using a different antihyperglycemic agent.

• cannabidiol

  isoniazid will increase the level or effect of cannabidiol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a strong CYP2C19 inhibitor.
  
  isoniazid will increase the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a strong CYP3A4 inhibitor.
  
  cannabidiol, rifampin. affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Owing to the potential for both CYP2B6 induction and inhibition with the coadministration of CYP2B6 substrates and cannabidiol, consider reducing dosage adjustment of CYP2B6 substrates as clinically appropriate.
  
  rifampin will decrease the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider an increase in cannabidiol dosage (based on clinical response and tolerability) when coadministered with a strong CYP3A4 inducer.

• carbamazepine

  isoniazid will increase the level or effect of carbamazepine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor plasma levels when used concomitantly

• carvedilol

  rifampin will decrease the level or effect of carvedilol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of carvedilol by increasing metabolism. Use Caution/Monitor.

• cariprazine

  isoniazid will increase the level or effect of cariprazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with strong CYP3A4 inhibitors requires cariprazine dose reduction. See Dosage Modification section in drug monograph.

• caspofungin

  rifampin decreases levels of caspofungin by increasing metabolism. Use Caution/Monitor.

• cenobamate

  cenobamate will decrease the level or effect of rifampin by affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP2B6 substrate, as needed, when coadministered with cenobamate.

• cevimeline

  rifampin will decrease the level or effect of cevimeline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of cevimeline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• chlordiazepoxide

  rifampin will decrease the level or effect of chlordiazepoxide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cilostazol

  isoniazid will increase the level or effect of cilostazol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• chloroquine

  rifampin will decrease the level or effect of chloroquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• chlorpropamide

  rifampin decreases levels of chlorpropamide by increasing metabolism. Use Caution/Monitor.

• cholic acid

  rifampin increases toxicity of cholic acid by decreasing elimination. Modify Therapy/Monitor Closely. Avoid concomitant use of inhibitors of the bile salt efflux pump (BSEP). May exacerbate accumulation of conjugated bile salts in the liver and result in clinical symptoms. If concomitant use is necessary, monitor serum transaminases and bilirubin.

• cimetidine

  isoniazid will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• cinacalcet

  isoniazid will increase the level or effect of cinacalcet by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• citalopram

  isoniazid will increase the level or effect of citalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Citalopram 20 mg/day is the maximum recommended dose for patients taking CYP2C19 inhibitors because of the risk of QT prolongation.
  
  rifampin will decrease the level or effect of citalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of citalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clarithromycin

  isoniazid will increase the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  rifampin will decrease the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clobazam

  isoniazid will increase the level or effect of clobazam by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Dosage adjustment may be required; CYP2C19 inhibitors may result in increased exposure to N-desmethylclobazam (active metabolite).

• clomipramine

  rifampin will decrease the level or effect of clomipramine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of clomipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clomipramine

  isoniazid will increase the level or effect of clomipramine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  clomipramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• clonazepam

  rifampin will decrease the level or effect of clonazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clopidogrel

  isoniazid will decrease the level or effect of clopidogrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Inhibition of CYP3A4 will reduce clopidogrel bioactivation

• clorazepate

  isoniazid will increase the level or effect of clorazepate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of clorazepate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clotrimazole

  clotrimazole will increase the level or effect of rifampin by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use with cotrimoxazole increase concentration of rifampin which may increase risk of toxicity; monitor for adverse reactions during coadministration

• clozapine

  isoniazid will increase the level or effect of clozapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of clozapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clozapine

  rifampin will decrease the level or effect of clozapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• cobicistat

  isoniazid will increase the level or effect of cobicistat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cocaine topical

  cocaine topical and isoniazid both increase serotonin levels. Use Caution/Monitor.

• codeine

  isoniazid decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• conjugated estrogens

  rifampin will decrease the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• conjugated estrogens, vaginal

  rifampin will decrease the level or effect of conjugated estrogens, vaginal by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• cortisone

  isoniazid will increase the level or effect of cortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of cortisone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• crizotinib

  rifampin decreases levels of crizotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Concomitant use of strong CYP3A inducers should be avoided. .
  
  crizotinib increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid increases levels of crizotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Concomitant use of strong CYP3A inhibitors should be avoided. .

• cyclophosphamide

  rifampin will decrease the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cycloserine

  isoniazid increases toxicity of cycloserine by decreasing metabolism. Use Caution/Monitor. Enhanced CNS toxicity; risk of seizure.

• cyclosporine

  rifampin will decrease the level or effect of cyclosporine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  rifampin will decrease the level or effect of cyclosporine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely.

• dantrolene

  rifampin will decrease the level or effect of dantrolene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dapsone

  rifampin will decrease the level or effect of dapsone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of dapsone by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of dapsone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• daridorexant

  isoniazid will increase the level or effect of daridorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Daridorexant dose should not exceed 25 mg per night when coadministered with moderate CYP3A4 inhibitors.

• daunorubicin

  rifampin will decrease the level or effect of daunorubicin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• darifenacin

  isoniazid will increase the level or effect of darifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• darunavir

  isoniazid will increase the level or effect of darunavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dasatinib

  isoniazid will increase the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• deferasirox

  rifampin decreases levels of deferasirox by Other (see comment). Use Caution/Monitor. Comment: Avoid concomitant use of potent UGT inducers with deferasirox. If co-administration is required then consider increasing initial dose of deferasirox to 30 mg/kg and monitor ferritin levels and clinical response.

• deflazacort

  isoniazid will increase the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease deflazacort dose to one-third of the recommended dose if coadministered with moderate or strong CYP3A4 inhibitors.
  
  rifampin will decrease the level or effect of deflazacort by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• desipramine

  desipramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• dexamethasone

  rifampin will decrease the level or effect of dexamethasone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• dexamethasone

  isoniazid will increase the level or effect of dexamethasone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dexfenfluramine

  dexfenfluramine and isoniazid both increase serotonin levels. Use Caution/Monitor.

• dexlansoprazole

  rifampin will decrease the level or effect of dexlansoprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of dexlansoprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• dextroamphetamine

  dextroamphetamine and isoniazid both increase serotonin levels. Use Caution/Monitor.

• dextromethorphan

  dextromethorphan and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• diazepam

  isoniazid will increase the level or effect of diazepam by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• diazepam intranasal

  isoniazid will increase the level or effect of diazepam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.
  
  rifampin will decrease the level or effect of diazepam intranasal by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Strong or moderate CYP2C19 inducers may increase rate of diazepam elimination; therefore, efficacy of diazepam may be decreased.
  
  rifampin will decrease the level or effect of diazepam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inducers may increase rate of diazepam elimination; therefore, efficacy of diazepam may be decreased.
  
  isoniazid will increase the level or effect of diazepam intranasal by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Strong or moderate CYP2C19 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.

• dichlorphenamide

  dichlorphenamide, isoniazid. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Both drugs can cause metabolic acidosis.

• digoxin

  rifampin will decrease the level or effect of digoxin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Reduced digoxin serum concentrations, possibly with a suboptimal therapeutic response, may be seen.
  
  rifampin decreases levels of digoxin by increasing metabolism. Use Caution/Monitor.

• dienogest/estradiol valerate

  isoniazid will increase the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor for potential adverse effects such as nausea, irregular uterine bleeding, breast tenderness and headache.

• dihydroergotamine

  dihydroergotamine and isoniazid both increase serotonin levels. Use Caution/Monitor.

• dihydroergotamine intranasal

  dihydroergotamine intranasal and isoniazid both increase serotonin levels. Use Caution/Monitor.

• disopyramide

  isoniazid will increase the level or effect of disopyramide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  rifampin will decrease the level or effect of disopyramide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• disulfiram

  disulfiram will increase the level or effect of isoniazid by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.
  
  isoniazid increases toxicity of disulfiram by decreasing metabolism. Use Caution/Monitor. Enhanced CNS toxicity.

• docetaxel

  rifampin will decrease the level or effect of docetaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of docetaxel by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• docetaxel

  isoniazid will increase the level or effect of docetaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• donepezil

  rifampin will decrease the level or effect of donepezil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• doravirine

  isoniazid will increase the level or effect of doravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of doravirine and CYP3A4 inhibitors may increase plasma concentrations and toxicities of doravirine.

• doxepin

  doxepin and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• doxepin cream

  rifampin will decrease the level or effect of doxepin cream by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• doxorubicin

  rifampin will decrease the level or effect of doxorubicin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of doxorubicin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of doxorubicin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• doxorubicin liposomal

  rifampin will decrease the level or effect of doxorubicin liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of doxorubicin liposomal by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of doxorubicin liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dronabinol

  rifampin will decrease the level or effect of dronabinol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Dronabinol is a CYP2C9 substrate.
  
  isoniazid will increase the level or effect of dronabinol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dronabinol is a CYP3A4 substrate.
  
  rifampin will decrease the level or effect of dronabinol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dronabinol is a CYP3A4 substrate.

• duloxetine

  isoniazid will increase the level or effect of duloxetine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  duloxetine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• dutasteride

  rifampin will decrease the level or effect of dutasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dutasteride

  isoniazid will increase the level or effect of dutasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• duvelisib

  rifampin will decrease the level or effect of duvelisib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• efavirenz

  rifampin will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• elagolix

  isoniazid will increase the level or effect of elagolix by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of elagolix 200 mg BID with strong CYP3A inhibitors for >1 month is not recommended. Limit elagolix dose to 150 mg qDay and CYP3A inhibitor duration of use to 6 months if coadministered.
  
  elagolix will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  rifampin will increase the level or effect of elagolix by Other (see comment). Modify Therapy/Monitor Closely. Limit concomitant use of elagolix 150 mg qDay and rifampin to 6 months.
  
  rifampin will decrease the level or effect of elagolix by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Limit concomitant use of elagolix 150 mg qDay and rifampin to 6 months.

• eletriptan

  isoniazid will increase the level or effect of eletriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  eletriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.

• eliglustat

  eliglustat increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the P-gp substrate and titrate to clinical effect.

• eltrombopag

  isoniazid will increase the level or effect of eltrombopag by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of eltrombopag by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of eltrombopag by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  eltrombopag increases levels of rifampin by decreasing metabolism. Use Caution/Monitor. OATP transporter protein inhibition.

• eluxadoline

  isoniazid increases levels of eluxadoline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. As a precautionary measure due to incomplete information on the metabolism of eluxadoline, use caution when coadministered with strong CYP2C19 inhibitors.

• encorafenib

  encorafenib will increase the level or effect of rifampin by Other (see comment). Modify Therapy/Monitor Closely. Encorafenib (a OATP1B1 and OATP1B3 inhibitor) may increase the concentration and toxicities of OATP1B1 and OATP1B3 substrates. Closely monitor for signs and symptoms of increased exposure and consider adjusting the dose of these substrates.

• elvitegravir

  isoniazid increases levels of elvitegravir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Elvitegravir is a CYP3A4 substrate; if coadministered with strong CYP3A4 inhibitors may increase levels.

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  isoniazid will increase the level or effect of elvitegravir/cobicistat/emtricitabine/tenofovir DF by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• enfortumab vedotin

  isoniazid increases toxicity of enfortumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Enfortumab vedotin is an antibody-drug conjugate that releases monomethylauristatin E (MMAE) via proteolytic cleavage. MMAE is primarily metabolized by CYP3A4 in vitro. Coadministration with strong CYP3A4 inhibitors may increase free MMAE exposure, which may increase the incidence or severity of toxicities.
  
  rifampin will decrease the level or effect of enfortumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• eplerenone

  rifampin will decrease the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ergotamine

  ergotamine and isoniazid both increase serotonin levels. Use Caution/Monitor.

• erlotinib

  rifampin will decrease the level or effect of erlotinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of erlotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• escitalopram

  escitalopram and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  rifampin will decrease the level or effect of escitalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of escitalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of escitalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• esomeprazole

  rifampin will decrease the level or effect of esomeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of esomeprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• estradiol vaginal

  isoniazid will increase the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase plasma concentrations of estrogens and toxicities.

• estradiol

  rifampin will decrease the level or effect of estradiol by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• estradiol vaginal

  rifampin will decrease the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• estrogens conjugated synthetic

  rifampin will decrease the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• estrogens esterified

  rifampin will decrease the level or effect of estrogens esterified by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• estropipate

  rifampin will decrease the level or effect of estropipate by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• eszopiclone

  rifampin will decrease the level or effect of eszopiclone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. According to prescribing information, zopiclone AUC was decreased 80% by concomitant use of rifampin. A similar effect would be expected with eszopiclone (S-enantiomer of zopiclone).

• ethanol

  isoniazid will increase the level or effect of ethanol by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor. Generally avoid; increased risk of hepatotoxicity

• ethionamide

  ethionamide increases levels of isoniazid by unspecified interaction mechanism. Use Caution/Monitor.

• ethosuximide

  rifampin will decrease the level or effect of ethosuximide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• ethotoin

  rifampin will decrease the level or effect of ethotoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• etonogestrel

  isoniazid will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• etoposide

  isoniazid will increase the level or effect of etoposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of etoposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of etoposide by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• etravirine

  isoniazid will increase the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of etravirine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of etravirine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• eucalyptus

  rifampin will decrease the level or effect of eucalyptus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• felodipine

  isoniazid will increase the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• exemestane

  rifampin will decrease the level or effect of exemestane by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. For patients receiving exemestane with a potent CYP3A4 inducer the recommended dose of exemestane is 50 mg daily after a meal.

• fenfluramine

  rifampin will decrease the level or effect of fenfluramine by Other (see comment). Modify Therapy/Monitor Closely. Coadministration with drugs that increase serotonin may increase the risk of serotonin syndrome.
  
  fenfluramine and isoniazid both increase serotonin levels. Use Caution/Monitor.

• fentanyl

  rifampin will decrease the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead to a decrease in fentanyl plasma concentrations, lack of efficacy or, possibly, development of a withdrawal syndrome in a patient who has developed physical dependence to fentanyl. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase which could increase or prolong both the therapeutic and adverse effects.

• fesoterodine

  isoniazid will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fentanyl intranasal

  rifampin will decrease the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead to a decrease in fentanyl plasma concentrations, lack of efficacy or, possibly, development of a withdrawal syndrome in a patient who has developed physical dependence to fentanyl. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase which could increase or prolong both the therapeutic and adverse effects.

• fentanyl transdermal

  rifampin will decrease the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead to a decrease in fentanyl plasma concentrations, lack of efficacy or, possibly, development of a withdrawal syndrome in a patient who has developed physical dependence to fentanyl. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase which could increase or prolong both the therapeutic and adverse effects.

• fentanyl transmucosal

  rifampin will decrease the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead to a decrease in fentanyl plasma concentrations, lack of efficacy or, possibly, development of a withdrawal syndrome in a patient who has developed physical dependence to fentanyl. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase which could increase or prolong both the therapeutic and adverse effects.

• finasteride

  rifampin will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• finerenone

  isoniazid will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.

• flibanserin

  rifampin will decrease the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inducers substantially decrease flibanserin systemic exposure.

• flibanserin

  isoniazid will increase the level or effect of flibanserin by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Coadministration of flibanserin with strong CYP2C19 inhibitors may increase flibanserin exposure and increase the risk of hypotension, syncope, and CNS depression.

• fluconazole

  rifampin decreases levels of fluconazole by increasing metabolism. Use Caution/Monitor.

• fludrocortisone

  rifampin will decrease the level or effect of fludrocortisone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of fludrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fluoxetine

  fluoxetine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• flurazepam

  rifampin will decrease the level or effect of flurazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fluticasone furoate

  isoniazid will increase the level or effect of fluticasone furoate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inhibitors may increase fluticasone systemic exposure

• fluticasone inhaled

  isoniazid will increase the level or effect of fluticasone inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inhibitors may increase fluticasone systemic exposure

• fluvastatin

  rifampin increases toxicity of fluvastatin by Other (see comment). Use Caution/Monitor. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• fluvoxamine

  fluvoxamine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• fosamprenavir

  isoniazid will increase the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fosaprepitant

  isoniazid will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fosphenytoin

  rifampin will decrease the level or effect of fosphenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• fostamatinib

  fostamatinib will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Concomitant use of fostamatinib may increase concentrations of P-gp substrates. Monitor for toxicities of the P-gp substrate drug that may require dosage reduction when given concurrently with fostamatinib.

• frovatriptan

  isoniazid will increase the level or effect of frovatriptan by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  frovatriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.

• galantamine

  rifampin will decrease the level or effect of galantamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of galantamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• gefitinib

  rifampin will decrease the level or effect of gefitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase gefitinib to 500 mg daily if coadministered with a strong CYP3A4 inducer. Resume gefitinib dose at 250 mg/day 7 days after discontinuing the strong inducer.
  
  isoniazid increases levels of gefitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of strong CYP3A4 inhibitors may increase risk for gefitinib adverse effects.

• gentamicin

  rifampin will decrease the level or effect of gentamicin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• glecaprevir/pibrentasvir

  isoniazid will increase the level or effect of glecaprevir/pibrentasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• glimepiride

  rifampin decreases levels of glimepiride by increasing metabolism. Use Caution/Monitor.

• glipizide

  rifampin decreases levels of glipizide by increasing metabolism. Use Caution/Monitor.

• glyburide

  rifampin decreases levels of glyburide by increasing metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of glyburide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Strong CYP2C9 inducers may increase glyburide metabolism.

• green tea

  green tea, isoniazid. Other (see comment). Use Caution/Monitor. Comment: Avoid combination or excessive consumption of green tea. Combination may increase risk of cardiac arrhythmias or severe hypertension can occur due to caffeine component of green tea.

• guanfacine

  isoniazid will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available.
  
  rifampin will decrease the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inducers significantly reduce guanfacine plasma concentrations and elimination half-life. If coadministered, more frequent dosing of the IR product may be required to achieve or maintain the desired hypotensive response. For patients with ADHD, FDA-approved labeling for ER guanfacine recommends that, if coadministered, doubling the recommended dose of guanfacine should be considered.

• haloperidol

  rifampin will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  isoniazid will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• hydrocodone

  rifampin will decrease the level or effect of hydrocodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Caution when discontinuing CYP3A4 inducers that are coadministered with hydrocodone; plasma concentrations of hydrocodone may increase and can result in potentially fatal respiratory depression
  
  isoniazid will increase the level or effect of hydrocodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with CYP3A4 inhibitors may increase hydrocodone plasma concentrations and can result in potentially fatal respiratory depression

• hydrocortisone

  rifampin will decrease the level or effect of hydrocortisone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of hydrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• hydroxyprogesterone caproate (DSC)

  isoniazid will increase the level or effect of hydroxyprogesterone caproate (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ifosfamide

  rifampin increases effects of ifosfamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Coadministration of ifosfamide with CYP2B6 inducers may increase metabolism of ifosfamide to its metabolite. Monitor for increased effects/toxicities if combined with CYP2B6 inducers.
  
  rifampin increases toxicity of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inducers may increase the metabolism of ifosfamide to its active alkylating metabolites. CYP3A4 inducers may increase the formation of the neurotoxic/nephrotoxic ifosfamide metabolite, chloroacetaldehyde. Closely monitor patients taking ifosfamide with CYP3A4 inducers for toxicities and consider dose adjustment.

• iloperidone

  isoniazid will increase the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• imatinib

  isoniazid will increase the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of imatinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• imipramine

  rifampin will decrease the level or effect of imipramine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of imipramine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of imipramine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of imipramine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  imipramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• indinavir

  isoniazid will increase the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of indinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• insulin degludec

  isoniazid decreases effects of insulin degludec by pharmacodynamic antagonism. Use Caution/Monitor. Isoniazid may increase blood glucose (rare).

• irinotecan

  rifampin will decrease the level or effect of irinotecan by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• insulin degludec/insulin aspart

  isoniazid decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Use Caution/Monitor. Isoniazid may increase blood glucose (rare).

• insulin inhaled

  isoniazid decreases effects of insulin inhaled by pharmacodynamic antagonism. Use Caution/Monitor. Isoniazid may increase blood glucose (rare).

• irinotecan liposomal

  rifampin will decrease the level or effect of irinotecan liposomal by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• isavuconazonium sulfate

  isoniazid will decrease the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isradipine

  rifampin will decrease the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• istradefylline

  isoniazid will increase the level or effect of istradefylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Do not exceed istradefylline 20 mg/day if coadministered with strong CYP3A4 inhibitors.
  
  istradefylline will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of P-gp substrates in clinical trials. Consider dose reduction of sensitive P-gp substrates.

• itraconazole

  rifampin will decrease the level or effect of itraconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid decreases levels of itraconazole by unspecified interaction mechanism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of itraconazole by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• ivacaftor

  isoniazid will increase the level or effect of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce ivacaftor dose if coadministered with strong CYP3A4 inhibitors. See specific ivacaftor-containing product for precise dosage modification.
  
  ivacaftor increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Ivacaftor and its M1 metabolite has the potential to inhibit P-gp; may significantly increase systemic exposure to sensitive P-gp substrates with a narrow therapeutic index.

• ivermectin

  rifampin will decrease the level or effect of ivermectin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• L-tryptophan

  isoniazid and L-tryptophan both increase serotonin levels. Use Caution/Monitor.

• ixabepilone

  isoniazid will increase the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ketamine

  rifampin will decrease the level or effect of ketamine by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of ketamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ketoconazole

  rifampin will decrease the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lacosamide

  isoniazid increases levels of lacosamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider decreasing lacosamide dose when coadministered with strong CYP3A4 inhibitors.

• lamotrigine

  rifampin decreases levels of lamotrigine by increasing metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of lamotrigine by increasing hepatic clearance. Use Caution/Monitor.

• lansoprazole

  isoniazid will increase the level or effect of lansoprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• lapatinib

  rifampin will decrease the level or effect of lapatinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lemborexant

  lemborexant will decrease the level or effect of rifampin by affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Monitor CYP2B6 substrate for adequate clinical response. Consider increasing the CYP2B6 substrate dose according to specific prescribing recommendations.

• levamlodipine

  isoniazid will increase the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate and strong CYP3A inhibitors results in increased systemic exposure to amlodipine and may require dose reduction. Monitor for symptoms of hypotension and edema when amlodipine is coadministered with CYP3A inhibitors to determine the need for dose adjustment.

• lesinurad

  rifampin will decrease the level or effect of lesinurad by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely.

• levamlodipine

  rifampin will decrease the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• levodopa inhaled

  isoniazid decreases effects of levodopa inhaled by altering metabolism. Use Caution/Monitor. Isoniazid may inhibit dopa-decarboxylase in the brain; thereby, preventing conversion of levodopa to active dopamine.

• levoketoconazole

  rifampin will decrease the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• levomilnacipran

  levomilnacipran and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  isoniazid will increase the level or effect of levomilnacipran by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Do not exceed 80 mg/day of levomilnacipran when coadministered with strong CYP3A4 inhibitors

• levonorgestrel intrauterine

  rifampin decreases levels of levonorgestrel intrauterine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• levonorgestrel oral

  rifampin decreases levels of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  isoniazid will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.
  
  rifampin will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.

• lidocaine

  isoniazid will increase the level or effect of lidocaine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of lidocaine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• linagliptin

  rifampin will decrease the level or effect of linagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of alternative treatments is strongly recommended when linagliptin is to be administered with a CYP3A4 inducer.
  
  rifampin will decrease the level or effect of linagliptin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Use of alternative treatments is strongly recommended when linagliptin is to be administered with a P-gp inducer.

• lithium

  isoniazid and lithium both increase serotonin levels. Use Caution/Monitor.

• lofepramine

  lofepramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  rifampin decreases levels of lofepramine by increasing metabolism. Use Caution/Monitor.

• lomitapide

  lomitapide increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing dose when used concomitantly with lomitapide.

• lopinavir

  isoniazid will increase the level or effect of lopinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• loperamide

  rifampin will decrease the level or effect of loperamide by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• loratadine

  isoniazid will increase the level or effect of loratadine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• losartan

  rifampin will decrease the level or effect of losartan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of losartan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lovastatin

  rifampin will decrease the level or effect of lovastatin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• lsd

  isoniazid and lsd both increase serotonin levels. Use Caution/Monitor.

• lumacaftor/ivacaftor

  lumacaftor/ivacaftor, rifampin. affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2B6 substrates. .
  
  isoniazid increases levels of lumacaftor/ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A inhibitors do not impact lumacaftor exposure, but increased ivacaftor exposure by 4.3-fold. Due to the induction effect of lumacaftor on CYP3A, at steady-state the net exposure of ivacaftor is not expected to exceed that when given in the absence of lumacaftor at a dose of 150 mg q12hr (the approved dose of ivacaftor monotherapy). Therefore, no dose adjustment is necessary when CYP3A inhibitors are initiated in patients currently taking lumacaftor/ivacaftor. However, when initiating lumacaftor/ivacaftor in patients taking strong CYP3A inhibitors, reduce the dose to 1 tablet daily (lumacaftor 200 mg/ivacaftor 125 mg total daily dose) for the first week of treatment to allow for the steady-state induction effect of lumacaftor. Following this period, continue with the recommended daily dose. No dose adjustment is required for moderate or weak CYP3A4 inhibitors.

• lumateperone

  isoniazid will increase the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce lumateperone dose to 21 mg/day if coadministered with moderate CYP3A4 inhibitors.

• maraviroc

  rifampin will decrease the level or effect of maraviroc by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• lumefantrine

  isoniazid will increase the level or effect of lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• maprotiline

  maprotiline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• maraviroc

  isoniazid will increase the level or effect of maraviroc by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Decrease maraviroc dose to 150 mg BID when coadministered with strong CYP3A4 inhibitors

• marijuana

  rifampin will decrease the level or effect of marijuana by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• mavacamten

  isoniazid will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• medroxyprogesterone

  isoniazid will increase the level or effect of medroxyprogesterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of medroxyprogesterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Contraceptirve failure possible

• mefloquine

  isoniazid will increase the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• meperidine

  isoniazid and meperidine both increase serotonin levels. Modify Therapy/Monitor Closely.

• mestranol

  rifampin will decrease the level or effect of mestranol by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• metformin

  isoniazid decreases effects of metformin by unspecified interaction mechanism. Use Caution/Monitor. Patient should be closely observed for loss of blood glucose control; when drugs are withdrawn from a patient receiving metformin, patient should be observed closely for hypoglycemia.

• methadone

  isoniazid will increase the level or effect of methadone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of methadone by increasing metabolism. Use Caution/Monitor.

• methylprednisolone

  rifampin will decrease the level or effect of methylprednisolone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of methylprednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• metoprolol

  rifampin decreases levels of metoprolol by increasing metabolism. Use Caution/Monitor.

• metronidazole

  metronidazole will increase the level or effect of isoniazid by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.

• mexiletine

  isoniazid will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• miconazole vaginal

  rifampin decreases levels of miconazole vaginal by increasing metabolism. Use Caution/Monitor.

• midazolam

  isoniazid will increase the level or effect of midazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• mifepristone

  rifampin will decrease the level or effect of mifepristone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inducers have not been studied, coadministration not recommended by manufacturer

• milnacipran

  milnacipran and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• mipomersen

  mipomersen, isoniazid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.
  
  mipomersen, rifampin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.

• mirtazapine

  isoniazid and mirtazapine both increase serotonin levels. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of mirtazapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• montelukast

  rifampin will decrease the level or effect of montelukast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• morphine

  isoniazid and morphine both increase serotonin levels. Use Caution/Monitor.

• nafcillin

  nafcillin decreases effects of rifampin by pharmacodynamic antagonism. Use Caution/Monitor. Nafcillin may show antagonistic effects against S. aureus.

• naldemedine

  isoniazid increases levels of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with strong or moderate CYP3A4 inhibitors.

• naratriptan

  naratriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.

• nefazodone

  rifampin will decrease the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nefazodone and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• nelfinavir

  isoniazid will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• neomycin PO

  rifampin will decrease the level or effect of neomycin PO by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• netupitant/palonosetron

  isoniazid will increase the level or effect of netupitant/palonosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Netupitant is mainly metabolized by CYP3A4; no dosage adjustment is required

• nicardipine

  isoniazid will increase the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nifedipine

  rifampin will decrease the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  isoniazid will increase the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nilotinib

  rifampin will decrease the level or effect of nilotinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• nimodipine

  isoniazid will increase the level or effect of nimodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nimodipine

  rifampin will decrease the level or effect of nimodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nitrendipine

  rifampin will decrease the level or effect of nitrendipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of nitrendipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• norgestrel

  rifampin will decrease the level or effect of norgestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of nonhormonal contraceptives advised

• nortriptyline

  nortriptyline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• olanzapine

  isoniazid will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• oliceridine

  isoniazid will increase the level or effect of oliceridine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.
  
  rifampin will decrease the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. If coadministration with a CYP3A4 inducer is necessary, consider increasing oliceridine dose until stable drug effects are achieved; monitor for signs of opioid withdrawal. If inducer is discontinued, consider oliceridine dosage reduction and monitor for signs of respiratory depression.
  
  isoniazid will increase the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.

• omeprazole

  rifampin will decrease the level or effect of omeprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• ondansetron

  isoniazid will increase the level or effect of ondansetron by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. CYP-450 inhibitors may decrease clearance of ondansetron. However, no dosage adjustment for ondansetron is recommended
  
  isoniazid will increase the level or effect of ondansetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP-450 inhibitors may decrease clearance of ondansetron. However, no dosage adjustment for ondansetron is recommended

• ondansetron

  rifampin will decrease the level or effect of ondansetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• osilodrostat

  rifampin will decrease the level or effect of osilodrostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of osilodrostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce dose of osilodrostat, a CYP3A4 substrate, by half when coadministered with a strong CYP3A4 inhibitor.
  
  rifampin will decrease the level or effect of osilodrostat by Other (see comment). Use Caution/Monitor. Osilodrostat is a CYP3A4 and CYP2B6 subtrate. Monitor cortisol concentration and patient?s signs and symptoms during coadministration and discontinuation with strong CYP3A4 and/or CYP2B6 inducers. Adjust dose of osilodrostat if necessary.

• ospemifene

  rifampin decreases levels of ospemifene by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of ospemifene by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  isoniazid increases levels of ospemifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid increases levels of ospemifene by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of ospemifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• oxybutynin

  rifampin will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• paclitaxel

  isoniazid will increase the level or effect of paclitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• oxycodone

  rifampin decreases levels of oxycodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• paclitaxel

  rifampin will decrease the level or effect of paclitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of paclitaxel by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of paclitaxel by Other (see comment). Use Caution/Monitor. Paclitaxel levels/efficacy may decrease when coadministered with CYP2C8 inducers

• paclitaxel protein bound

  rifampin will decrease the level or effect of paclitaxel protein bound by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of paclitaxel protein bound by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of paclitaxel protein bound by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of paclitaxel protein bound by Other (see comment). Use Caution/Monitor. Paclitaxel levels/efficacy may decrease when coadministered with CYP2C8 inducers

• paliperidone

  rifampin will decrease the level or effect of paliperidone by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Paliperidone dose may need to be increased when coadministered with strong inducers of both CYP3A4 and P-gp

• panobinostat

  isoniazid increases levels of panobinostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce panobinostat starting dose to 10 mg if coadministered with strong CYP3A4 inhibitors.

• pantoprazole

  rifampin will decrease the level or effect of pantoprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• parecoxib

  rifampin will decrease the level or effect of parecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of parecoxib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• paromomycin

  rifampin will decrease the level or effect of paromomycin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• paroxetine

  paroxetine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• pazopanib

  isoniazid will increase the level or effect of pazopanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of pazopanib with strong CYP3A4 inhibitors if possible; if must coadminister, decrease pazopanib dose to 400 mg/day

• pentazocine

  isoniazid and pentazocine both increase serotonin levels. Use Caution/Monitor.

• pentobarbital

  rifampin decreases levels of pentobarbital by increasing metabolism. Use Caution/Monitor.

• phenobarbital

  rifampin decreases levels of phenobarbital by increasing metabolism. Use Caution/Monitor.

• phenytoin

  rifampin will decrease the level or effect of phenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• pimavanserin

  rifampin will decrease the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration if possible. Monitor for reduced pimavanserin efficacy. An increase in pimavanserin dosage may be needed.

• pimozide

  isoniazid will increase the level or effect of pimozide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of pimozide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• pioglitazone

  rifampin will decrease the level or effect of pioglitazone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• polatuzumab vedotin

  isoniazid will increase the level or effect of polatuzumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Polatuzumab undergoes catabolism to small peptides, amino acids, monomethyl auristatin E (MMAE), and unconjugated MMAE-related catabolites. MMAE is a CYP3A4 substrate. Coadministration of polatuzumab vedotin with a strong CYP3A4 inhibitor may increase unconjugated MMAE AUC, which may increase polatuzumab vedotin toxicities.

• pitavastatin

  rifampin increases levels of pitavastatin by decreasing metabolism. Use Caution/Monitor. Do not exceed 2 mg/d pitavastatin.

• pitolisant

  rifampin will decrease the level or effect of pitolisant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Pitolisant exposure is decreased by 50% if coadministered with strong CYP3A4 inducers. For patients stable on pitolisant 8.9 mg/day or 17.8 mg/day, double the pitolisant dose (ie, 17.8 mg or 35.6 mg, respectively) over 7 days. If the strong CYP3A4 inducer is discontinued, reduce pitolisant dosage by half.

• polatuzumab vedotin

  rifampin will decrease the level or effect of polatuzumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Polatuzumab undergoes catabolism to small peptides, amino acids, monomethyl auristatin E (MMAE), and unconjugated MMAE-related catabolites. MMAE is a CYP3A4 substrate. Coadministration of polatuzumab vedotin with a strong CYP3A4 inducer may decrease unconjugated MMAE AUC.

• ponatinib

  ponatinib increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• posaconazole

  rifampin will decrease the level or effect of posaconazole by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  rifampin decreases levels of posaconazole by increasing metabolism. Use Caution/Monitor.

• pravastatin

  rifampin increases toxicity of pravastatin by Other (see comment). Use Caution/Monitor. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• prednisolone

  rifampin will decrease the level or effect of prednisolone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of prednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• prednisone

  rifampin will decrease the level or effect of prednisone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of prednisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• primidone

  rifampin decreases levels of primidone by increasing metabolism. Use Caution/Monitor.

• propafenone

  isoniazid will increase the level or effect of propafenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• probenecid

  probenecid will increase the level or effect of rifampin by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use with probenecid increase concentration of rifampin which may increase risk of toxicity; monitor for adverse reactions during coadministration

• propafenone

  rifampin will decrease the level or effect of propafenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of propafenone by increasing metabolism. Use Caution/Monitor.

• propranolol

  rifampin decreases levels of propranolol by increasing metabolism. Use Caution/Monitor.

• protriptyline

  protriptyline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• quetiapine

  isoniazid will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• quinidine

  isoniazid will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• quinine

  rifampin will decrease the level or effect of quinine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of quinine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rabeprazole

  rifampin will decrease the level or effect of rabeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ramelteon

  isoniazid will increase the level or effect of ramelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• raltegravir

  rifampin decreases levels of raltegravir by increasing hepatic clearance. Use Caution/Monitor.

• ramelteon

  rifampin will decrease the level or effect of ramelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of ramelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rasagiline

  rifampin will decrease the level or effect of rasagiline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Rifampin is a relatively weak inducer of CYP1A2, caution is advised.
  
  rasagiline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  isoniazid will increase the level or effect of rasagiline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Isoniazid shows only negligible inhibition of CYP1A2, caution is advised. Recommended dose of rasagiline is 0.5mg daily in combination with CYP1A2 inhibitors.

• repaglinide

  isoniazid will increase the level or effect of repaglinide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• riociguat

  rifampin will decrease the level or effect of riociguat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Data not available for dose adjustment

• rilpivirine

  isoniazid increases levels of rilpivirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• riluzole

  isoniazid will increase the level or effect of riluzole by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• ripretinib

  isoniazid will increase the level or effect of ripretinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with a strong CYP3A inhibitor will increase systemic exposure to ripretinib and its active metabolite (DP-5439), which may increase risk of adverse reactions.

• risperidone

  rifampin will decrease the level or effect of risperidone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• ritonavir

  isoniazid will increase the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of ritonavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• rivaroxaban

  rifampin decreases levels of rivaroxaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid concomitant use of rivaroxaban with drugs that are combined P-gp and strong CYP3A4 inducers. Consider increasing the rivaroxaban dose if these drugs must be coadministered.

• rizatriptan

  rizatriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.

• romidepsin

  isoniazid will increase the level or effect of romidepsin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of romidepsin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• ropinirole

  rifampin will decrease the level or effect of ropinirole by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of ropinirole by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• rosuvastatin

  rifampin increases toxicity of rosuvastatin by Other (see comment). Use Caution/Monitor. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• SAMe

  isoniazid and SAMe both increase serotonin levels. Use Caution/Monitor.

• safinamide

  isoniazid, safinamide. Either increases toxicity of the other by serotonin levels. Modify Therapy/Monitor Closely. Monitor for hypertension and reaction to dietary tyramine in patients treated concomitantly with isoniazid and safinamide.

• ruxolitinib

  rifampin will decrease the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ruxolitinib topical

  rifampin will decrease the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• sacubitril/valsartan

  rifampin will increase the level or effect of sacubitril/valsartan by Other (see comment). Use Caution/Monitor. The results from an in vitro study with human liver tissue indicate that valsartan is a substrate of the hepatic uptake transporter OATP1B1; coadministration with OATP1B1 inhibitors may increase valsartan systemic exposure

• saquinavir

  isoniazid will increase the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• sarecycline

  sarecycline will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor for toxicities of P-gp substrates that may require dosage reduction when coadministered with P-gp inhibitors.

• saxagliptin

  isoniazid will increase the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Limit saxagliptin dose to 2.5 mg/day when coadministered with strong CYP3A4 inhibitors
  
  rifampin will decrease the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• secobarbital

  rifampin decreases levels of secobarbital by increasing metabolism. Use Caution/Monitor.

• selegiline

  selegiline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• selegiline

  rifampin will decrease the level or effect of selegiline by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.

• selegiline transdermal

  selegiline transdermal and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• selexipag

  rifampin will decrease the level or effect of selexipag by increasing metabolism. Modify Therapy/Monitor Closely. Coadministration of selexipag with rifampin, an inducer of CYP2C8, UGT1A3, and 2B7 enzymes, decreased exposure to selexipag's active metabolite by 50%. Increase selexipag dose up to twice of the typical dose if coadministered with rifampin.

• sertraline

  sertraline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• sevoflurane

  isoniazid will increase the level or effect of sevoflurane by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.

• sildenafil

  rifampin will decrease the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potent CYP3A4 inducers are expected to cause substantial decreases in sildenafil plasma levels
  
  isoniazid will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• silodosin

  rifampin will decrease the level or effect of silodosin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• sodium bicarbonate

  sodium bicarbonate decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• simvastatin

  rifampin will increase the level or effect of simvastatin by Other (see comment). Use Caution/Monitor. OATP1B1 inhibitors may increase risk of myopathy

• sirolimus

  rifampin will decrease the level or effect of sirolimus by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• sodium bicarbonate

  sodium bicarbonate will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids

• sodium citrate/citric acid

  sodium citrate/citric acid decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• sodium picosulfate/magnesium oxide/anhydrous citric acid

  rifampin decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.
  
  isoniazid decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.

• sodium sulfate/?magnesium sulfate/potassium chloride

  sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of isoniazid by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.
  
  sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of rifampin by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sodium sulfate/potassium sulfate/magnesium sulfate

  sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of rifampin by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.
  
  sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of isoniazid by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• solifenacin

  isoniazid will increase the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• sparsentan

  sparsentan will decrease the level or effect of rifampin by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Sparsentan (a CYP2B6 inducer) decreases exposure of CYP2B6 substrates and reduces efficacy related to these substrates.

• St John's Wort

  isoniazid and St John's Wort both increase serotonin levels. Modify Therapy/Monitor Closely.

• stiripentol

  stiripentol, rifampin. affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP2B6 inhibitor and inducer. Monitor CYP2B6 substrates coadministered with stiripentol for increased or decreased effects. CYP2B6 substrates may require dosage adjustment.
  
  stiripentol will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing the dose of P-glycoprotein (P-gp) substrates, if adverse reactions are experienced when administered concomitantly with stiripentol.

• streptomycin

  rifampin will decrease the level or effect of streptomycin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• sufentanil

  rifampin will decrease the level or effect of sufentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of sufentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• sufentanil SL

  rifampin decreases effects of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of CYP3A4 inducers may decrease sufentanil levels and efficacy, possibly precipitating withdrawal syndrome in patients who have developed physical dependence to sufentanil. Discontinuation of concomitantly used CYP3A4 inducers may increase sufentanil plasma concentration.
  
  isoniazid will increase the level or effect of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of sufentanil SL with any CYP3A4 inhibitor may increase sufentanil plasma concentration, and, thereby increase or prolonged adverse effects, including potentially fatal respiratory depression.

• sumatriptan

  sumatriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.

• suvorexant

  rifampin will decrease the level or effect of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inducers may decrease suvorexant efficacy; if increased suvorexant dose required, do not exceed 20 mg/day

• sumatriptan intranasal

  sumatriptan intranasal and isoniazid both increase serotonin levels. Use Caution/Monitor.

• sunitinib

  isoniazid will increase the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tacrolimus

  rifampin will decrease the level or effect of tacrolimus by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tadalafil

  rifampin will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid combination in pulmonary HTN patients. For patients with ED, monitor response to tadalafil carefully because of potential for decreased effectiveness.
  
  isoniazid will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. For ED limit tadalafil to max of 2.5 mg/day (for daily use) or 10 mg dose every 72 hr (for use as needed). Avoid concurrent use of tadalafil for pulmonary HTN in patients taking strong CYP3A4 inhibitors.

• tamoxifen

  rifampin will decrease the level or effect of tamoxifen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of tamoxifen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid, tamoxifen. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. CYP3A4 inhibition decreases metabolism of tamoxifen to N-desmethyl tamoxifen (active metabolite with similar biologic activity).

• tamsulosin

  isoniazid increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• tasimelteon

  rifampin will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers

• tasimelteon

  isoniazid will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• temsirolimus

  isoniazid will increase the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• teniposide

  rifampin will decrease the level or effect of teniposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• terbinafine

  rifampin will decrease the level or effect of terbinafine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of terbinafine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of terbinafine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tetracycline

  rifampin will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tezacaftor

  isoniazid will increase the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust tezacaftor dosage regimen if coadministered with a strong CYP3A inhibitor.

• theophylline

  isoniazid will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• tiagabine

  rifampin will decrease the level or effect of tiagabine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• tipranavir

  isoniazid will increase the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ticagrelor

  rifampin decreases levels of ticagrelor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid use of ticagrelor with potent CYP3A inducers.

• tinidazole

  rifampin will decrease the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tisotumab vedotin

  isoniazid increases levels of tisotumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tisotumab vedotin?s active metabolite (MMAE) is a CYP3A4 substrate. Coadministration with strong CYP3A4 inhibitors may increase unconjugated MMAE systemic exposure and increase risk of adverse effects.

• tobramycin

  rifampin will decrease the level or effect of tobramycin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• tofacitinib

  rifampin will decrease the level or effect of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Loss of, or decreased response to tofacitinib may occur when coadministered with potent CYP3A4 inducers
  
  isoniazid increases levels of tofacitinib by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. No specific dose adjustment recommended when tofacitinib coadministered with potent CYP2C19 inhibitors; decrease tofacitinib dose if coadministered with both moderate CYP3A4 and potent CYP2C19 inhibitors .

• tolazamide

  rifampin decreases levels of tolazamide by increasing metabolism. Use Caution/Monitor.

• tolterodine

  isoniazid will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tolbutamide

  rifampin decreases levels of tolbutamide by increasing metabolism. Use Caution/Monitor.

• tolvaptan

  rifampin will decrease the level or effect of tolvaptan by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• toremifene

  rifampin decreases levels of toremifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inducers increase rate of toremifene metabolism, lowering the steady-state concentration in serum.
  
  isoniazid increases levels of toremifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Metabolism of toremifene may be inhibited by drugs known to inhibit CYP3A4 hepatic enzymes.

• tramadol

  rifampin will decrease the level or effect of tramadol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Decreased AUC of tramadol and the active metabolite (O-desmethyltramadol) when coadministered with strong CYP3A4 and CYP2B6 inducers
  
  isoniazid and tramadol both increase serotonin levels. Use Caution/Monitor.

• trazodone

  isoniazid will increase the level or effect of trazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  trazodone and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• trimethoprim

  rifampin will decrease the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• triamcinolone acetonide injectable suspension

  isoniazid will increase the level or effect of triamcinolone acetonide injectable suspension by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• triazolam

  isoniazid will increase the level or effect of triazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• trimipramine

  rifampin will decrease the level or effect of trimipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  trimipramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• tucatinib

  tucatinib will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Consider reducing the dosage of P-gp substrates, where minimal concentration changes may lead to serious or life-threatening toxicities.

• ubrogepant

  isoniazid will decrease the level or effect of ubrogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Dose adjustment is recommended with concomitant use of ubrogepant and moderate and weak CYP3A4 inducers. (see Dosage Modifications)

• umeclidinium bromide/vilanterol inhaled

  isoniazid will increase the level or effect of umeclidinium bromide/vilanterol inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Vilanterol is a CYP3A4 substrate; coadministration with potent CYP3A4 inhibitors may increase systemic exposure

• upadacitinib

  isoniazid will increase the level or effect of upadacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution if upadacitinib is coadministered with strong CYP3A4 inhibitors.

• valbenazine

  isoniazid will increase the level or effect of valbenazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce valbenazine dose to 40 mg once daily when coadministered with a strong CYP3A4 inhibitor.

• valsartan

  rifampin will increase the level or effect of valsartan by Other (see comment). Use Caution/Monitor. The results from an in vitro study with human liver tissue indicate that valsartan is a substrate of the hepatic uptake transporter OATP1B1; coadministration with OATP1B1 inhibitors may increase valsartan systemic exposure

• vardenafil

  isoniazid will increase the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Vardenafil dose may need to be reduced if coadministered with moderate or strong CYP3A4 inhibitors

• vemurafenib

  vemurafenib increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  rifampin decreases levels of vemurafenib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• venlafaxine

  venlafaxine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• verapamil

  isoniazid will increase the level or effect of verapamil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• vilanterol/fluticasone furoate inhaled

  isoniazid will increase the level or effect of vilanterol/fluticasone furoate inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Fluticasone furoate and vilanterol are both CYP3A4 substrates; coadministration with potent CYP3A4 inhibitors may increase systemic exposure

• vilazodone

  rifampin decreases levels of vilazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Consider increasing vilazodone dose up to 2-fold (not to exceed 80 mg/day) when coadministered with strong CYP3A4 inducers for >14 days.

• vinblastine

  rifampin will decrease the level or effect of vinblastine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of vinblastine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of vinblastine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• vincristine

  rifampin will decrease the level or effect of vincristine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of vincristine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of vincristine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• vincristine liposomal

  rifampin will decrease the level or effect of vincristine liposomal by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of vincristine liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of vincristine liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• vinorelbine

  rifampin will decrease the level or effect of vinorelbine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of vinorelbine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• voriconazole

  isoniazid will increase the level or effect of voriconazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• vortioxetine

  rifampin decreases levels of vortioxetine by increasing metabolism. Modify Therapy/Monitor Closely. Consider increasing the vortioxetine dose when coadministered with strong CYP inducers for >14 days; not to exceed 3 times original vortioxetine dose.
  
  rifampin will decrease the level or effect of vortioxetine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider increasing vortioxetine dose when coadministered with a strong CYP inducer for >14 days. Do not exceed 3x the original dose. Reduce vortioxetine dose to original level within 14 days, when inducer is discontinued.

• warfarin

  isoniazid will increase the level or effect of warfarin by Other (see comment). Use Caution/Monitor. Warfarin's less potent R-enantiomer is metabolized in part by CYP3A4 (and also CYP1A2 and CYP2C19). Monitor INR more frequently if coadministered with inhibitors of these isoenzymes and adjust warfarin dose if needed.
  
  rifampin will decrease the level or effect of warfarin by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely.

• zaleplon

  rifampin will decrease the level or effect of zaleplon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• zanubrutinib

  isoniazid will increase the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce zanubrutinib (a CYP3A4 substrate) to 80 mg PO BID to when coadministered with a moderate CYP3A4 inhibitor. Interrupt dose as recommended for adverse reactions. After discontinuing the CYP3A4 inhibitor, resume previous dose of zanubrutinib.

• zidovudine

  rifampin decreases levels of zidovudine by increasing metabolism. Use Caution/Monitor.

• ziprasidone

  rifampin will decrease the level or effect of ziprasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• zolmitriptan

  zolmitriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.

• zolpidem

  rifampin will decrease the level or effect of zolpidem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• zonisamide

  isoniazid will increase the level or effect of zonisamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of zonisamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

Minor (132)

• acarbose

  isoniazid decreases effects of acarbose by unspecified interaction mechanism. Minor/Significance Unknown.

• acetaminophen

  rifampin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
  
  isoniazid increases toxicity of acetaminophen by unknown mechanism. Minor/Significance Unknown.

• acetaminophen IV

  isoniazid increases toxicity of acetaminophen IV by unknown mechanism. Minor/Significance Unknown.
  
  rifampin decreases levels of acetaminophen IV by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• acetaminophen rectal

  rifampin decreases levels of acetaminophen rectal by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
  
  isoniazid increases toxicity of acetaminophen rectal by unknown mechanism. Minor/Significance Unknown.

• aliskiren

  rifampin will decrease the level or effect of aliskiren by P-glycoprotein (MDR1) efflux transporter. Minor/Significance Unknown.

• ambrisentan

  isoniazid will increase the level or effect of ambrisentan by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
  
  isoniazid will increase the level or effect of ambrisentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• alosetron

  rifampin will decrease the level or effect of alosetron by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• alvimopan

  rifampin will decrease the level or effect of alvimopan by P-glycoprotein (MDR1) efflux transporter. Minor/Significance Unknown.

• amitriptyline

  isoniazid will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ampicillin

  rifampin decreases levels of ampicillin by increasing metabolism. Minor/Significance Unknown.

• antipyrine

  isoniazid will increase the level or effect of antipyrine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

• asenapine

  isoniazid will increase the level or effect of asenapine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

• bazedoxifene/conjugated estrogens

  isoniazid will increase the level or effect of bazedoxifene/conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• bentonite

  bentonite decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• bisoprolol

  rifampin decreases levels of bisoprolol by increasing metabolism. Minor/Significance Unknown.

• budesonide

  budesonide decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• caffeine

  rifampin will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
  
  isoniazid will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

• calcium acetate

  isoniazid decreases levels of calcium acetate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• celecoxib

  rifampin will decrease the level or effect of celecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• calcium carbonate

  isoniazid decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• calcium chloride

  isoniazid decreases levels of calcium chloride by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• calcium citrate

  isoniazid decreases levels of calcium citrate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• calcium gluconate

  isoniazid decreases levels of calcium gluconate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• chloramphenicol

  rifampin decreases levels of chloramphenicol by increasing metabolism. Minor/Significance Unknown.

• chlordiazepoxide

  rifampin decreases levels of chlordiazepoxide by increasing metabolism. Minor/Significance Unknown.

• chlorpropamide

  isoniazid decreases effects of chlorpropamide by unspecified interaction mechanism. Minor/Significance Unknown.

• cimetidine

  rifampin will decrease the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• clofazimine

  clofazimine decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• clomipramine

  isoniazid will increase the level or effect of clomipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• conjugated estrogens

  isoniazid will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• conjugated estrogens, vaginal

  isoniazid will increase the level or effect of conjugated estrogens, vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• cortisone

  cortisone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• deflazacort

  deflazacort decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• dexamethasone

  dexamethasone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• diazepam

  rifampin will decrease the level or effect of diazepam by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• diclofenac

  rifampin will decrease the level or effect of diclofenac by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• didanosine

  didanosine, isoniazid. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Enhanced risk of peripheral neuropathy.

• donepezil

  isoniazid will increase the level or effect of donepezil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• enalapril

  rifampin decreases levels of enalapril by increasing metabolism. Minor/Significance Unknown.

• estradiol

  isoniazid will increase the level or effect of estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• estrogens conjugated synthetic

  isoniazid will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• estrogens esterified

  isoniazid will increase the level or effect of estrogens esterified by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• estropipate

  isoniazid will increase the level or effect of estropipate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ethanol

  isoniazid increases toxicity of ethanol by decreasing metabolism. Minor/Significance Unknown. Enhanced hepatotoxicity.
  
  ethanol decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Interaction more likely with chronic EtOH use.

• ethotoin

  isoniazid increases levels of ethotoin by decreasing metabolism. Minor/Significance Unknown.

• fexofenadine

  rifampin will decrease the level or effect of fexofenadine by P-glycoprotein (MDR1) efflux transporter. Minor/Significance Unknown.

• eucalyptus

  isoniazid will increase the level or effect of eucalyptus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• fluconazole

  fluconazole decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Only applies to oral preparations of both agents.

• fludrocortisone

  fludrocortisone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• flurbiprofen

  rifampin will decrease the level or effect of flurbiprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• fluvastatin

  rifampin will decrease the level or effect of fluvastatin by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
  
  rifampin decreases levels of fluvastatin by increasing metabolism. Minor/Significance Unknown.

• food

  food decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• fosinopril

  rifampin decreases levels of fosinopril by increasing metabolism. Minor/Significance Unknown.

• fosphenytoin

  isoniazid increases levels of fosphenytoin by decreasing metabolism. Minor/Significance Unknown.

• frovatriptan

  rifampin will decrease the level or effect of frovatriptan by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

• ganaxolone

  isoniazid, ganaxolone. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. Changes in ganaxolone exposures when coadministered with strong, moderate, or weak CYP3A4 inhibitors are not expected to be clinically significant.

• glimepiride

  isoniazid decreases effects of glimepiride by unspecified interaction mechanism. Minor/Significance Unknown.

• glipizide

  isoniazid decreases effects of glipizide by unspecified interaction mechanism. Minor/Significance Unknown.

• glyburide

  isoniazid decreases effects of glyburide by unspecified interaction mechanism. Minor/Significance Unknown.

• hydrocortisone

  hydrocortisone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• ibuprofen

  rifampin will decrease the level or effect of ibuprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• ibuprofen IV

  rifampin will decrease the level or effect of ibuprofen IV by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• imidapril

  rifampin decreases levels of imidapril by increasing metabolism. Minor/Significance Unknown.

• imipramine

  isoniazid will increase the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• insulin aspart

  isoniazid decreases effects of insulin aspart by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin detemir

  isoniazid decreases effects of insulin detemir by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin glargine

  isoniazid decreases effects of insulin glargine by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin glulisine

  isoniazid decreases effects of insulin glulisine by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin lispro

  isoniazid decreases effects of insulin lispro by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin NPH

  isoniazid decreases effects of insulin NPH by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin regular human

  isoniazid decreases effects of insulin regular human by unspecified interaction mechanism. Minor/Significance Unknown.

• isosorbide dinitrate

  rifampin will decrease the level or effect of isosorbide dinitrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• isosorbide mononitrate

  rifampin will decrease the level or effect of isosorbide mononitrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ixazomib

  isoniazid, ixazomib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. In clinical trials, coadministration of ixazomib with strong CYP3A inhibitors did not result in a clinically meaningful change in the systemic exposure of ixazomib.

• ketoconazole

  ketoconazole decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Only applies to oral preparations of both agents.
  
  isoniazid will increase the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• lansoprazole

  rifampin will decrease the level or effect of lansoprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• levoketoconazole

  isoniazid will increase the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• leflunomide

  rifampin increases effects of leflunomide by increasing metabolism. Minor/Significance Unknown. Leflunomide's effects due to its active metabolite.

• levoketoconazole

  levoketoconazole decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Only applies to oral preparations of both agents.

• levothyroxine

  rifampin decreases levels of levothyroxine by increasing metabolism. Minor/Significance Unknown.

• liothyronine

  rifampin decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.

• lisinopril

  rifampin decreases levels of lisinopril by increasing metabolism. Minor/Significance Unknown.

• loratadine

  rifampin will decrease the level or effect of loratadine by P-glycoprotein (MDR1) efflux transporter. Minor/Significance Unknown.

• meloxicam

  rifampin will decrease the level or effect of meloxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
  
  rifampin decreases levels of meloxicam by increasing metabolism. Minor/Significance Unknown.

• mestranol

  isoniazid will increase the level or effect of mestranol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• methylprednisolone

  methylprednisolone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• miconazole vaginal

  miconazole vaginal decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Only applies to oral preparations of both agents.

• miglitol

  isoniazid decreases effects of miglitol by unspecified interaction mechanism. Minor/Significance Unknown.

• modafinil

  rifampin will decrease the level or effect of modafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• moexipril

  rifampin decreases levels of moexipril by increasing metabolism. Minor/Significance Unknown.

• montelukast

  isoniazid will increase the level or effect of montelukast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• morphine

  rifampin decreases levels of morphine by increasing metabolism. Minor/Significance Unknown.

• nateglinide

  isoniazid decreases effects of nateglinide by unspecified interaction mechanism. Minor/Significance Unknown.

• nevirapine

  rifampin decreases levels of nevirapine by increasing metabolism. Minor/Significance Unknown.

• niacin

  isoniazid decreases levels of niacin by pharmacodynamic antagonism. Minor/Significance Unknown.

• nortriptyline

  rifampin decreases levels of nortriptyline by increasing metabolism. Minor/Significance Unknown.

• ondansetron

  rifampin will decrease the level or effect of ondansetron by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

• opium tincture

  rifampin decreases levels of opium tincture by increasing metabolism. Minor/Significance Unknown.

• oxacillin

  rifampin decreases levels of oxacillin by increasing metabolism. Minor/Significance Unknown.

• oxybutynin

  isoniazid will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• parecoxib

  isoniazid will increase the level or effect of parecoxib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• perindopril

  rifampin decreases levels of perindopril by increasing metabolism. Minor/Significance Unknown.

• phenytoin

  isoniazid increases levels of phenytoin by decreasing metabolism. Minor/Significance Unknown.

• pioglitazone

  isoniazid will increase the level or effect of pioglitazone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  isoniazid decreases effects of pioglitazone by unspecified interaction mechanism. Minor/Significance Unknown.

• pirmenol

  rifampin decreases levels of pirmenol by increasing metabolism. Minor/Significance Unknown.

• piroxicam

  rifampin will decrease the level or effect of piroxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• posaconazole

  posaconazole decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Only applies to oral preparations of both agents.

• prednisolone

  prednisolone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• prednisone

  prednisone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• primaquine

  primaquine, isoniazid. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hemolysis in G6PD deficient pts.

• pyrazinamide

  isoniazid, pyrazinamide. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive hepatotoxicity.

• pyridoxine

  isoniazid decreases levels of pyridoxine by unspecified interaction mechanism. Minor/Significance Unknown. If INH dose >10 mg/kg/day, supplement 50 100mg pyridoxine/day.

• pyridoxine (Antidote)

  isoniazid decreases levels of pyridoxine (Antidote) by unspecified interaction mechanism. Minor/Significance Unknown. If INH dose >10 mg/kg/day, supplement 50 100mg pyridoxine/day.

• quinapril

  rifampin decreases levels of quinapril by increasing metabolism. Minor/Significance Unknown.

• rabeprazole

  isoniazid will increase the level or effect of rabeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
  
  rifampin will decrease the level or effect of rabeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• ramelteon

  rifampin will decrease the level or effect of ramelteon by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
  
  isoniazid will increase the level or effect of ramelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ramipril

  rifampin decreases levels of ramipril by increasing metabolism. Minor/Significance Unknown.

• repaglinide

  isoniazid decreases effects of repaglinide by unspecified interaction mechanism. Minor/Significance Unknown.

• riluzole

  rifampin will decrease the level or effect of riluzole by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

• rosiglitazone

  isoniazid decreases effects of rosiglitazone by unspecified interaction mechanism. Minor/Significance Unknown.

• sitagliptin

  isoniazid decreases effects of sitagliptin by unspecified interaction mechanism. Minor/Significance Unknown.

• sulfamethoxazole

  rifampin will decrease the level or effect of sulfamethoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• thyroid desiccated

  rifampin decreases levels of thyroid desiccated by increasing metabolism. Minor/Significance Unknown.

• tibolone

  rifampin decreases levels of tibolone by increasing metabolism. Minor/Significance Unknown. Theoretical interaction.

• tolazamide

  isoniazid decreases effects of tolazamide by unspecified interaction mechanism. Minor/Significance Unknown.

• tolbutamide

  isoniazid decreases effects of tolbutamide by unspecified interaction mechanism. Minor/Significance Unknown.
  
  rifampin will decrease the level or effect of tolbutamide by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• trandolapril

  rifampin decreases levels of trandolapril by increasing metabolism. Minor/Significance Unknown.

• triamcinolone acetonide injectable suspension

  triamcinolone acetonide injectable suspension decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• valproic acid

  isoniazid increases levels of valproic acid by decreasing metabolism. Minor/Significance Unknown.

• vildagliptin

  isoniazid decreases effects of vildagliptin by unspecified interaction mechanism. Minor/Significance Unknown.

• voriconazole

  voriconazole decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Only applies to oral preparations of both agents.

• zaleplon

  isoniazid will increase the level or effect of zaleplon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• 5-HTP

  Monitor Closely (1)5-HTP and isoniazid both increase serotonin levels. Use Caution/Monitor.

• abametapir

  Serious - Use Alternative (1)abametapir will increase the level or effect of rifampin by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP2B6 substrates. If not feasible, avoid use of abametapir.

• abemaciclib

  Monitor Closely (1)isoniazid will increase the level or effect of abemaciclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A4 inhibitors increase plasma levels of abemaciclib and its metabolites. Abemaciclib dose reduction required. If a strong CYP3A4 inhibitor is discontinued, increase abemaciclib to the dose prior to initiating the strong inhibitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of abemaciclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of abemaciclib with strong CYP3A4 inducers reduces plasma concentration of abemaciclib and its metabolites.

• abiraterone

  Monitor Closely (1)rifampin decreases levels of abiraterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid coadministration of abiraterone with strong CYP3A4 inducers; if a strong CYP3A4 inducer must be used, increase abiraterone dosage frequency from once daily to twice daily.

• abrocitinib

  Monitor Closely (1)isoniazid will increase the level or effect of abrocitinib by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Start abrocitinib 50 mg qDay when coadministered with CYP2C19 inhibitors. If adequate response not achieved after 12 weeks, may increase to 100 mg qDay. Discontinue if inadequate response after dosage increase.Serious - Use Alternative (1)rifampin will decrease the level or effect of abrocitinib by increasing metabolism. Avoid or Use Alternate Drug. Abrocitinib is a CYP2C9 and CYP2C19 substrate. Drugs that are strong inducers of CYP2C19 or CYP2C9 decreases the combined exposure of abrocitinib and its active metabolites, resulting in loss of or reduced clinical response.

• acalabrutinib

  Serious - Use Alternative (2)rifampin will decrease the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of acalabrutinib with strong CYP3A inducers. If a strong CYP3A inducer must be used, increase acalabrutinib dose to 200 mg twice daily.
  
  isoniazid will increase the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of acalabrutinib with strong CYP3A inhibitors. If a strong CYP3A inhibitor must be used short-term (eg, up to 7 days), temporarily interrupt treatment with acalabrutinib.

• acarbose

  Minor (1)isoniazid decreases effects of acarbose by unspecified interaction mechanism. Minor/Significance Unknown.

• acetaminophen

  Monitor Closely (1)isoniazid will increase the level or effect of acetaminophen by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.Minor (2)rifampin decreases levels of acetaminophen by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
  
  isoniazid increases toxicity of acetaminophen by unknown mechanism. Minor/Significance Unknown.

• acetaminophen IV

  Monitor Closely (1)isoniazid will increase the level or effect of acetaminophen IV by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.Minor (2)isoniazid increases toxicity of acetaminophen IV by unknown mechanism. Minor/Significance Unknown.
  
  rifampin decreases levels of acetaminophen IV by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.

• acetaminophen rectal

  Monitor Closely (1)isoniazid will increase the level or effect of acetaminophen rectal by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.Minor (2)rifampin decreases levels of acetaminophen rectal by increasing metabolism. Minor/Significance Unknown. Enhanced metabolism incr levels of hepatotoxic metabolites.
  
  isoniazid increases toxicity of acetaminophen rectal by unknown mechanism. Minor/Significance Unknown.

• adagrasib

  Serious - Use Alternative (1)rifampin will decrease the level or effect of adagrasib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ado-trastuzumab emtansine

  Serious - Use Alternative (1)isoniazid increases levels of ado-trastuzumab emtansine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. DM1, the cytotoxic component, is metabolized mainly by CYP3A4; strong CYP3A4 inhibitors may increase DM1 exposure and toxicity.

• afatinib

  Serious - Use Alternative (1)rifampin decreases levels of afatinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Increase afatinib daily dose by 10 mg as tolerated if chronic therapy with P-gp inducer required; resume previous afatinib dose 2-3 days after P-gp inducer discontinued.

• alfentanil

  Monitor Closely (1)rifampin will decrease the level or effect of alfentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)isoniazid will increase the level or effect of alfentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Monitor for excessive CNS and respiratory depression

• alfuzosin

  Monitor Closely (1)rifampin will decrease the level or effect of alfuzosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)isoniazid will increase the level or effect of alfuzosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• aliskiren

  Minor (1)rifampin will decrease the level or effect of aliskiren by P-glycoprotein (MDR1) efflux transporter. Minor/Significance Unknown.

• almotriptan

  Monitor Closely (2)isoniazid will increase the level or effect of almotriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  almotriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of almotriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• alosetron

  Monitor Closely (4)rifampin will decrease the level or effect of alosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of alosetron by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of alosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of alosetron by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Minor (1)rifampin will decrease the level or effect of alosetron by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• alpelisib

  Serious - Use Alternative (1)rifampin will decrease the level or effect of alpelisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of alpelisib (CYP3A4 substrate) with strong CYP3A4 inducers.

• alprazolam

  Monitor Closely (1)isoniazid will increase the level or effect of alprazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of alprazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• aluminum hydroxide

  Monitor Closely (2)aluminum hydroxide will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids
  
  aluminum hydroxide decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• aluminum hydroxide/magnesium carbonate

  Monitor Closely (1)aluminum hydroxide/magnesium carbonate will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids

• aluminum hydroxide/magnesium trisilicate

  Monitor Closely (1)aluminum hydroxide/magnesium trisilicate will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids

• alvimopan

  Minor (1)rifampin will decrease the level or effect of alvimopan by P-glycoprotein (MDR1) efflux transporter. Minor/Significance Unknown.

• ambrisentan

  Monitor Closely (2)rifampin will decrease the level or effect of ambrisentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration was associated with a transient 2-fold increase in ambrisentan AUC; however, by day 7, rifampin had no clinically important effect on ambrisentan. Use with caution.
  
  rifampin will decrease the level or effect of ambrisentan by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.Minor (2)isoniazid will increase the level or effect of ambrisentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  isoniazid will increase the level or effect of ambrisentan by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• amifampridine

  Monitor Closely (1)isoniazid increases toxicity of amifampridine by Other (see comment). Modify Therapy/Monitor Closely. Comment: Amifampridine can cause seizures. Coadministration with drugs that lower seizure threshold may increase this risk.

• amikacin

  Monitor Closely (1)rifampin will decrease the level or effect of amikacin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• amiodarone

  Monitor Closely (1)isoniazid will increase the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• amitriptyline

  Monitor Closely (5)rifampin will decrease the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  amitriptyline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  rifampin will decrease the level or effect of amitriptyline by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• amlodipine

  Monitor Closely (1)rifampin will decrease the level or effect of amlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• amobarbital

  Monitor Closely (1)rifampin decreases levels of amobarbital by increasing metabolism. Use Caution/Monitor.

• amoxapine

  Monitor Closely (1)amoxapine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• ampicillin

  Minor (1)rifampin decreases levels of ampicillin by increasing metabolism. Minor/Significance Unknown.

• antipyrine

  Monitor Closely (1)rifampin will decrease the level or effect of antipyrine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of antipyrine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

• apalutamide

  Monitor Closely (2)apalutamide will decrease the level or effect of rifampin by increasing elimination. Use Caution/Monitor. Apalutamide weakly induces OATP1B1 and may decrease systemic exposure of drugs that are OATP1B1 substrates.
  
  isoniazid will increase the level or effect of apalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of apalutamide with strong CYP3A4 or CYP2C8 inhibitors does not require initial dosage modification; however, dose reduction may be needed based on tolerability.

• apixaban

  Serious - Use Alternative (1)rifampin will decrease the level or effect of apixaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Rifampin, a combined P-gp and strong CYP3A4 inducer, may decrease exposure to apixaban.

• apremilast

  Serious - Use Alternative (1)rifampin will decrease the level or effect of apremilast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong CYP inducers results in a significant decrease of systemic exposure of apremilast, which may result in loss of efficacy

• aprepitant

  Monitor Closely (1)isoniazid will increase the level or effect of aprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of aprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• aripiprazole

  Monitor Closely (1)isoniazid will increase the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• armodafinil

  Monitor Closely (3)isoniazid will increase the level or effect of armodafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of armodafinil by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of armodafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• artemether/lumefantrine

  Contraindicated (1)rifampin will decrease the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration with strong CYP3A4 inducers can result in decreased serum concentrations and loss of antimalarial efficacyMonitor Closely (1)isoniazid will increase the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• artesunate

  Monitor Closely (1)rifampin will decrease the level or effect of artesunate by increasing metabolism. Use Caution/Monitor. Coadministration may decrease AUC and peak plasma concentration of active artesunate metabolite (DHA) by inducing UGT. Monitor for decreased efficacy.

• asenapine

  Monitor Closely (1)rifampin will decrease the level or effect of asenapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of asenapine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

• atazanavir

  Contraindicated (1)rifampin decreases levels of atazanavir by increasing metabolism. Contraindicated. Contraindicated. May result in loss of antiviral efficacy and/or development of viral resistance.Monitor Closely (1)isoniazid will increase the level or effect of atazanavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of atazanavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• atogepant

  Monitor Closely (3)isoniazid will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Recommended atogepant dosage is 10 mg PO qDay when coadministered with strong CYP3A4 inhibitors.
  
  rifampin will increase the level or effect of atogepant by Other (see comment). Modify Therapy/Monitor Closely. Recommended dosage of atogepant (an OATP1B1 substrate) with concomitant use of OATP inhibitors is 10 mg or 30 mg qDay.
  
  rifampin will decrease the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Recommended atogepant dosage with concomitant use of strong or moderate CYP3A4 inducers is 30 mg or 60 mg qDay.

• atorvastatin

  Monitor Closely (2)isoniazid will increase the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of atorvastatin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)rifampin increases toxicity of atorvastatin by Other (see comment). Avoid or Use Alternate Drug. Comment: OATP1B1 inhibitors may increase risk of myopathy.
  
  rifampin will decrease the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• atovaquone

  Monitor Closely (1)rifampin decreases levels of atovaquone by increasing metabolism. Use Caution/Monitor.

• avanafil

  Monitor Closely (1)rifampin will decrease the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. For patients with ED, monitor response carefully because of potential for decreased effectiveness.Serious - Use Alternative (1)isoniazid will increase the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; significantly increased levels may result in significant adverse events including severe hypotension, syncope, visual changes, and priapism. Coadministration with strong CYP3A4 is contraindicated.

• avapritinib

  Serious - Use Alternative (2)rifampin will decrease the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of avapritinib with moderate CYP3A4 inhibitors. If unable to avoid, reduce avapritinib starting dose. See drug monograph Dosage Modifications.

• avatrombopag

  Monitor Closely (1)rifampin will decrease the level or effect of avatrombopag by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. When treating ITP, coadministration of avatrombopag with a moderate or strong dual CYP2C9/3A4 inducer requires an increased avatrombopag starting dose. Refer to drug monograph for specific recommendations.

• axitinib

  Serious - Use Alternative (2)rifampin decreases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Selection of concomitant medication with no or minimal CYP3A4 induction potential is recommended.
  
  isoniazid increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with strong CYP3A4 inhibitors, reduce axitinib dose by 50%.

• azithromycin

  Monitor Closely (1)azithromycin will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• bazedoxifene/conjugated estrogens

  Monitor Closely (1)rifampin will decrease the level or effect of bazedoxifene/conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)rifampin will decrease the level or effect of bazedoxifene/conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin decreases levels of bazedoxifene/conjugated estrogens by increasing metabolism. Avoid or Use Alternate Drug. A reduction in bazedoxifene exposure may be associated with an increase risk of endometrial hyperplasia.Minor (1)isoniazid will increase the level or effect of bazedoxifene/conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• BCG vaccine live

  Serious - Use Alternative (1)rifampin decreases levels of BCG vaccine live by pharmacodynamic antagonism. Contraindicated.

• bedaquiline

  Serious - Use Alternative (2)isoniazid will increase the level or effect of bedaquiline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of bedaquiline with strong CYP3A4 inhibitors for >14 consecutive days, unless the benefit of treatment outweighs the risk
  
  rifampin will decrease the level or effect of bedaquiline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of bedaquiline with strong CYP3A4 inducers due to potential for decreased therapeutic effect

• belumosudil

  Monitor Closely (1)rifampin will decrease the level or effect of belumosudil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase belumosudil dosage to 200 mg PO BID when coadministered with strong CYP3A inducers.

• belzutifan

  Monitor Closely (1)isoniazid will increase the level or effect of belzutifan by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Belzutifan is a CYP2C19 substrate. Coadministration with CYP2C19 inhibitors may increase incidence or severity of adverse effects. Monitor for anemia and hypoxia and reduce belzutifan dose as recommended.

• bendamustine

  Monitor Closely (1)rifampin decreases levels of bendamustine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Concentrations of active metabolites may be increased.

• bentonite

  Minor (1)bentonite decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• benzhydrocodone/acetaminophen

  Monitor Closely (2)isoniazid will increase the level or effect of benzhydrocodone/acetaminophen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with strong CYP3A4 inhibitors may increase hydrocodone (benzhydrocodone is prodrug of hydrocodone) plasma concentrations and can result in potentially fatal respiratory depression.
  
  rifampin will decrease the level or effect of benzhydrocodone/acetaminophen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Caution when discontinuing CYP3A4 inducers that are coadministered with benzhydrocodone (prodrug of hydrocodone); plasma concentrations of hydrocodone may increase and can result in potentially fatal respiratory depression.

• berotralstat

  Monitor Closely (1)berotralstat will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor or titrate P-gp substrate dose if coadministered.Serious - Use Alternative (1)rifampin decreases levels of berotralstat by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• bexagliflozin

  Monitor Closely (1)rifampin will decrease the level or effect of bexagliflozin by Other (see comment). Modify Therapy/Monitor Closely. Bexagliflozin is a major substrate of UGT1A9. If coadministered with a UGT1A9 inducer, consider adding another antihyperglycemic agent in patients requiring additional glycemic control.

• bexarotene

  Monitor Closely (2)rifampin will decrease the level or effect of bexarotene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of bexarotene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• bictegravir

  Contraindicated (1)rifampin will decrease the level or effect of bictegravir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of strong CYP3A and UGT1A1 inducers can substantially decrease bictegravir plasma concentrations. This may result in the loss of therapeutic effect and development of resistance to bictegravir. Coadministration with rifampin is contraindicated.

• bisoprolol

  Minor (1)rifampin decreases levels of bisoprolol by increasing metabolism. Minor/Significance Unknown.

• bortezomib

  Monitor Closely (2)rifampin will decrease the level or effect of bortezomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of bortezomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• bosentan

  Monitor Closely (3)rifampin will decrease the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of bosentan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• bosutinib

  Monitor Closely (1)bosutinib increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)isoniazid increases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors increases bosutinib plasma concentration ~5-fold.
  
  rifampin decreases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inducers decreased bosutinib plasma concentration by ~85%.

• brentuximab vedotin

  Monitor Closely (2)isoniazid increases levels of brentuximab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor patients for adverse reactions. .
  
  rifampin decreases levels of brentuximab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• brexpiprazole

  Monitor Closely (3)isoniazid will increase the level or effect of brexpiprazole by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. Administer a quarter of brexpiprazole dose if coadministered with a moderate CYP2D6 inhibitor PLUS a strong/moderate CYP3A4 inhibitor.
  
  rifampin will decrease the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Double brexpiprazole dose over 1-2 weeks if administered with a strong CYP3A4 inducer.
  
  isoniazid will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Administer half of the usual brexpiprazole dose when coadministered with strong CYP3A4 inhibitors. If also administered with a strong/moderate CYP2D6 inhibitor, administer a quarter of brexpiprazole dose.

• brigatinib

  Serious - Use Alternative (2)isoniazid will increase the level or effect of brigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use of a strong CYP3A inhibitor cannot be avoided, reduce the brigatinib once daily dose by about 50% (ie, from 180 mg to 90 mg, or from 90 mg to 60 mg). After discontinuation of a strong CYP3A inhibitor, resume the brigatinib dose that was tolerated prior to initiating the strong CYP3A inhibitor.
  
  rifampin will decrease the level or effect of brigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong CYP3A4 inducers may decrease brigatinib efficacy.

• brivaracetam

  Monitor Closely (1)rifampin will decrease the level or effect of brivaracetam by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. The dose of brivaracetam should be increased up to 100% (ie, double the dosage) in patients while receiving concomitant treatment with rifampin.

• bromocriptine

  Monitor Closely (1)rifampin will decrease the level or effect of bromocriptine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• budesonide

  Monitor Closely (2)isoniazid will increase the level or effect of budesonide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of budesonide by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of budesonide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)budesonide decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• buprenorphine

  Monitor Closely (1)rifampin will decrease the level or effect of buprenorphine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• buprenorphine buccal

  Monitor Closely (1)rifampin will decrease the level or effect of buprenorphine buccal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• buprenorphine subdermal implant

  Monitor Closely (2)rifampin will decrease the level or effect of buprenorphine subdermal implant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor patients already on buprenorphine subdermal implant who require newly-initiated treatment with CYP3A4 inducer for signs and symptoms of withdrawal. If the dose of the concomitant CYP3A4 inducer cannot be reduced or discontinued, implant removal may be necessary and the patient should then be treated with a buprenorphine dosage form that permits dose adjustments. If a CYP3A4 inducer is discontinued in a patient who has been stabilized on buprenorphine, monitor the patient for overmedication.
  
  isoniazid will increase the level or effect of buprenorphine subdermal implant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor patients already on buprenorphine subdermal implant who require newly-initiated treatment with CYP3A4 inhibitors for signs and symptoms of overmedication. If the dose of the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, implant removal may be necessary and the patient should then be treated with a buprenorphine dosage form that permits dose adjustments. If a CYP3A4 inhibitor is discontinued in a patient who has been stabilized on buprenorphine, monitor the patient for withdrawal.

• buprenorphine transdermal

  Monitor Closely (1)rifampin will decrease the level or effect of buprenorphine transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If coadministration is necessary, consider increasing buprenorphine transdermal dosage until stable. Monitor for signs of opioid withdrawal. If CYP3A4 inducer is discontinued, consider reducing the buprenorphine dosage and monitor for signs of respiratory depression.

• buprenorphine, long-acting injection

  Monitor Closely (2)rifampin will decrease the level or effect of buprenorphine, long-acting injection by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inducers should be monitored to ensure buprenorphine plasma levels are adequate. If the buprenorphine dose is inadequate and the CYP3A4 inducer cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.
  
  isoniazid will increase the level or effect of buprenorphine, long-acting injection by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inhibitors should be monitored to ensure buprenorphine plasma levels are adequate. Within 2 weeks, if signs and symptoms of buprenorphine toxicity or overdose occur and the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.

• bupropion

  Monitor Closely (1)rifampin will decrease the level or effect of bupropion by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.

• buspirone

  Monitor Closely (2)isoniazid will increase the level or effect of buspirone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  buspirone and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)rifampin will decrease the level or effect of buspirone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• butabarbital

  Monitor Closely (1)rifampin decreases levels of butabarbital by increasing metabolism. Use Caution/Monitor.

• butalbital

  Monitor Closely (1)rifampin decreases levels of butalbital by increasing metabolism. Use Caution/Monitor.

• cabazitaxel

  Monitor Closely (1)rifampin will decrease the level or effect of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of strong CYP3A4 inducers may decrease cabazitaxel concentrations. Avoid coadministration.Serious - Use Alternative (1)isoniazid will increase the level or effect of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of cabazitaxel with strong CYP3A4 inhibitors should be avoided.

• cabotegravir

  Contraindicated (1)rifampin will increase the level or effect of cabotegravir by increasing metabolism. Contraindicated. Cabotegravir is metabolized by UGT1A1 and UGT1A9. Strong UGT1A1 or UGT1A9 inducers decrease cabotegravir systemic exposure, thereby increasing potential for loss of virologic response.

• cabozantinib

  Serious - Use Alternative (2)rifampin will decrease the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of cabozantinib with strong CYP3A4 inducers. If a strong CYP3A4 inducer is required, increase cabozantinib dose by 40 mg/day (Cometriq) or by 20 mg/day (Cabometyx). Resume previous dose 2-3 days after strong CYP3A4 inducer discontinued.
  
  isoniazid will increase the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of cabozantinib with strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor is required, decrease cabozantinib dose by 40 mg/day (Cometriq) or by 20 mg/day (Cabometyx). Resume previous dose 2-3 days after strong CYP3A4 inhibitor discontinued.

• caffeine

  Minor (2)rifampin will decrease the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.
  
  isoniazid will increase the level or effect of caffeine by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

• calcifediol

  Monitor Closely (2)rifampin, calcifediol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Drugs that stimulate microsomal hydroxylation reduce the half-life of calcifediol.
  
  isoniazid, calcifediol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. CYP450 inhibitors may inhibit enzymes involved in vitamin D metabolism (CYP24A1 and CYP27B1). This may alter serum levels of calcifediol and decrease the conversion of calcifediol to calcitriol. Dose adjustment of calcifediol may be required, and serum 25­hydroxyvitamin D, intact PTH, and serum calcium concentrations should be closely monitored when initiating or discontinuing a strong CYP3A4 inhibitor.

• calcitriol

  Monitor Closely (1)rifampin will decrease the level or effect of calcitriol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• calcium acetate

  Minor (1)isoniazid decreases levels of calcium acetate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• calcium carbonate

  Monitor Closely (2)calcium carbonate will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids
  
  calcium carbonate decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.Minor (1)isoniazid decreases levels of calcium carbonate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• calcium chloride

  Minor (1)isoniazid decreases levels of calcium chloride by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• calcium citrate

  Minor (1)isoniazid decreases levels of calcium citrate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• calcium gluconate

  Minor (1)isoniazid decreases levels of calcium gluconate by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• calcium/vitamin D

  Monitor Closely (1)calcium/vitamin D will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids

• canagliflozin

  Monitor Closely (1)rifampin decreases levels of canagliflozin by increasing metabolism. Use Caution/Monitor. Coadministration with potent UGT enzyme inducers: Consider increasing dose to 300 mg qDay if 100 mg/day tolerate and additional glycemic control required (eGFR must be >60 mL/min/1.73 m2 to increase dose); if eGFR <60 mL/min/1.73 m2, consider using a different antihyperglycemic agent.

• cannabidiol

  Monitor Closely (4)isoniazid will increase the level or effect of cannabidiol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a strong CYP2C19 inhibitor.
  
  isoniazid will increase the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a strong CYP3A4 inhibitor.
  
  cannabidiol, rifampin. affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Owing to the potential for both CYP2B6 induction and inhibition with the coadministration of CYP2B6 substrates and cannabidiol, consider reducing dosage adjustment of CYP2B6 substrates as clinically appropriate.
  
  rifampin will decrease the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider an increase in cannabidiol dosage (based on clinical response and tolerability) when coadministered with a strong CYP3A4 inducer.

• capmatinib

  Serious - Use Alternative (1)rifampin will decrease the level or effect of capmatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• carbamazepine

  Monitor Closely (1)isoniazid will increase the level or effect of carbamazepine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor plasma levels when used concomitantlySerious - Use Alternative (1)rifampin will decrease the level or effect of carbamazepine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• cariprazine

  Contraindicated (1)rifampin will decrease the level or effect of cariprazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. CYP3A4 is responsible for the formation and elimination of cariprazine's active metabolites. The effect of CYP3A4 inducers on cariprazine exposure has not been evaluated and the net effect is unclear.Monitor Closely (1)isoniazid will increase the level or effect of cariprazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with strong CYP3A4 inhibitors requires cariprazine dose reduction. See Dosage Modification section in drug monograph.

• carvedilol

  Monitor Closely (2)rifampin will decrease the level or effect of carvedilol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of carvedilol by increasing metabolism. Use Caution/Monitor.

• caspofungin

  Monitor Closely (1)rifampin decreases levels of caspofungin by increasing metabolism. Use Caution/Monitor.

• celecoxib

  Minor (1)rifampin will decrease the level or effect of celecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• cenobamate

  Monitor Closely (1)cenobamate will decrease the level or effect of rifampin by affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP2B6 substrate, as needed, when coadministered with cenobamate.

• ceritinib

  Serious - Use Alternative (2)isoniazid increases levels of ceritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid if possible; if concomitant use is unavoidable, reduce ceritinib dose by ~33%; after discontinuation of strong CYP3A inhibitor, resume at previous dose.
  
  rifampin decreases levels of ceritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• cevimeline

  Monitor Closely (2)rifampin will decrease the level or effect of cevimeline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of cevimeline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• chloramphenicol

  Minor (1)rifampin decreases levels of chloramphenicol by increasing metabolism. Minor/Significance Unknown.

• chlordiazepoxide

  Monitor Closely (1)rifampin will decrease the level or effect of chlordiazepoxide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)rifampin decreases levels of chlordiazepoxide by increasing metabolism. Minor/Significance Unknown.

• chloroquine

  Monitor Closely (1)rifampin will decrease the level or effect of chloroquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• chlorpropamide

  Monitor Closely (1)rifampin decreases levels of chlorpropamide by increasing metabolism. Use Caution/Monitor.Minor (1)isoniazid decreases effects of chlorpropamide by unspecified interaction mechanism. Minor/Significance Unknown.

• cholic acid

  Monitor Closely (1)rifampin increases toxicity of cholic acid by decreasing elimination. Modify Therapy/Monitor Closely. Avoid concomitant use of inhibitors of the bile salt efflux pump (BSEP). May exacerbate accumulation of conjugated bile salts in the liver and result in clinical symptoms. If concomitant use is necessary, monitor serum transaminases and bilirubin.

• cilostazol

  Monitor Closely (1)isoniazid will increase the level or effect of cilostazol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)rifampin will decrease the level or effect of cilostazol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid increases toxicity of cilostazol by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Decrease cilostazol dose by 50%; serum levels of 3,4-dehydrocilostazol (active metabolite) increased by strong CYP2C19 inhibitors.

• cimetidine

  Monitor Closely (1)isoniazid will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.Minor (1)rifampin will decrease the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• cinacalcet

  Monitor Closely (1)isoniazid will increase the level or effect of cinacalcet by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of cinacalcet by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• citalopram

  Monitor Closely (3)rifampin will decrease the level or effect of citalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of citalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Citalopram 20 mg/day is the maximum recommended dose for patients taking CYP2C19 inhibitors because of the risk of QT prolongation.
  
  rifampin will decrease the level or effect of citalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clarithromycin

  Monitor Closely (2)isoniazid will increase the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  rifampin will decrease the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clobazam

  Monitor Closely (1)isoniazid will increase the level or effect of clobazam by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Dosage adjustment may be required; CYP2C19 inhibitors may result in increased exposure to N-desmethylclobazam (active metabolite).

• clofazimine

  Minor (1)clofazimine decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• clomipramine

  Monitor Closely (4)rifampin will decrease the level or effect of clomipramine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  clomipramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  isoniazid will increase the level or effect of clomipramine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of clomipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of clomipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• clonazepam

  Monitor Closely (1)rifampin will decrease the level or effect of clonazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clopidogrel

  Monitor Closely (1)isoniazid will decrease the level or effect of clopidogrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Inhibition of CYP3A4 will reduce clopidogrel bioactivationSerious - Use Alternative (2)isoniazid decreases effects of clopidogrel by decreasing metabolism. Avoid or Use Alternate Drug. Cytochrome P450 2C19 inhibitors decrease the conversion of clopidogrel to its active form.
  
  rifampin will increase the level or effect of clopidogrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP3A4 inducers may increase the metabolism of clopidogrel to its active metabolite. Monitor patients for potential increase in antiplatelet effects when CYP3A4 inducers are used in combination with clopidogrel

• clorazepate

  Monitor Closely (2)isoniazid will increase the level or effect of clorazepate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of clorazepate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clotrimazole

  Monitor Closely (1)clotrimazole will increase the level or effect of rifampin by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use with cotrimoxazole increase concentration of rifampin which may increase risk of toxicity; monitor for adverse reactions during coadministration

• clozapine

  Monitor Closely (3)isoniazid will increase the level or effect of clozapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of clozapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of clozapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of clozapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• cobicistat

  Contraindicated (1)rifampin will decrease the level or effect of cobicistat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration with rifampin is contraindicated due to potential for loss of therapeutic effect and development of resistance. Monitor Closely (1)isoniazid will increase the level or effect of cobicistat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cobimetinib

  Contraindicated (2)rifampin will decrease the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid coadministration. Strong or moderate CYP3A inducers may decrease cobimetinib systemic exposure by >80% and reduce its efficacy.
  
  isoniazid will increase the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid coadministration with strong CYP3A4 inhibitors with (increases cobimetinib systemic exposure by 6.7-fold).

• cocaine topical

  Monitor Closely (1)cocaine topical and isoniazid both increase serotonin levels. Use Caution/Monitor.

• codeine

  Monitor Closely (1)isoniazid decreases effects of codeine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor. Prevents conversion of codeine to its active metabolite morphine.

• colchicine

  Serious - Use Alternative (1)rifampin will decrease the level or effect of colchicine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• conivaptan

  Contraindicated (1)isoniazid will increase the level or effect of conivaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of conivaptan with strong CYP3A4 inhibitors is contraindicated.Serious - Use Alternative (1)rifampin will decrease the level or effect of conivaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• conjugated estrogens

  Monitor Closely (1)rifampin will decrease the level or effect of conjugated estrogens by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)isoniazid will increase the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• conjugated estrogens, vaginal

  Monitor Closely (1)rifampin will decrease the level or effect of conjugated estrogens, vaginal by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of conjugated estrogens, vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)isoniazid will increase the level or effect of conjugated estrogens, vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• copanlisib

  Serious - Use Alternative (2)rifampin will decrease the level or effect of copanlisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of copanlisib with strong CYP3A4 inducers.
  
  isoniazid will increase the level or effect of copanlisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use with strong CYP3A inhibitors cannot be avoided, reduce copanlisib dose to 45 mg.

• cortisone

  Monitor Closely (2)isoniazid will increase the level or effect of cortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of cortisone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of cortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)cortisone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• crizotinib

  Monitor Closely (3)rifampin decreases levels of crizotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Concomitant use of strong CYP3A inducers should be avoided. .
  
  crizotinib increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid increases levels of crizotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Concomitant use of strong CYP3A inhibitors should be avoided. .

• cyclophosphamide

  Monitor Closely (2)rifampin will decrease the level or effect of cyclophosphamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cycloserine

  Monitor Closely (1)isoniazid increases toxicity of cycloserine by decreasing metabolism. Use Caution/Monitor. Enhanced CNS toxicity; risk of seizure.

• cyclosporine

  Monitor Closely (2)rifampin will decrease the level or effect of cyclosporine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  rifampin will decrease the level or effect of cyclosporine by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely.

• dabigatran

  Serious - Use Alternative (1)rifampin will decrease the level or effect of dabigatran by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Avoid coadministration. P-gp inducers reduce systemic exposure of dabigatran

• dabrafenib

  Serious - Use Alternative (3)rifampin decreases levels of dabrafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid increases levels of dabrafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin decreases levels of dabrafenib by increasing metabolism. Avoid or Use Alternate Drug. Strong CYP2C8 inducers may decrease dabrafenib levels.

• dantrolene

  Monitor Closely (1)rifampin will decrease the level or effect of dantrolene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dapsone

  Monitor Closely (3)rifampin will decrease the level or effect of dapsone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of dapsone by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of dapsone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• daridorexant

  Monitor Closely (1)isoniazid will increase the level or effect of daridorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Daridorexant dose should not exceed 25 mg per night when coadministered with moderate CYP3A4 inhibitors.Serious - Use Alternative (1)rifampin will decrease the level or effect of daridorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• darifenacin

  Monitor Closely (1)isoniazid will increase the level or effect of darifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of darifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• darolutamide

  Serious - Use Alternative (1)rifampin will decrease the level or effect of darolutamide by Other (see comment). Avoid or Use Alternate Drug. Darolutamide is a P-gp and CYP3A4 substrate. Avoid coadminstration of darolutamide with combined P-gp and strong or moderate CYP3A4 inducers.

• darunavir

  Contraindicated (1)rifampin decreases levels of darunavir by increasing metabolism. Contraindicated. Contraindicated. May result in loss of antiviral efficacy and/or development of viral resistance.Monitor Closely (1)isoniazid will increase the level or effect of darunavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of darunavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• dasatinib

  Monitor Closely (1)isoniazid will increase the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• daunorubicin

  Monitor Closely (1)rifampin will decrease the level or effect of daunorubicin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• deferasirox

  Monitor Closely (1)rifampin decreases levels of deferasirox by Other (see comment). Use Caution/Monitor. Comment: Avoid concomitant use of potent UGT inducers with deferasirox. If co-administration is required then consider increasing initial dose of deferasirox to 30 mg/kg and monitor ferritin levels and clinical response.

• deflazacort

  Monitor Closely (2)isoniazid will increase the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease deflazacort dose to one-third of the recommended dose if coadministered with moderate or strong CYP3A4 inhibitors.
  
  rifampin will decrease the level or effect of deflazacort by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of deflazacort with moderate or strong CYP3A4 inducers.Minor (1)deflazacort decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• desipramine

  Monitor Closely (1)desipramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• desvenlafaxine

  Serious - Use Alternative (1)isoniazid and desvenlafaxine both increase serotonin levels. Avoid or Use Alternate Drug.

• dexamethasone

  Monitor Closely (2)rifampin will decrease the level or effect of dexamethasone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of dexamethasone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of dexamethasone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)dexamethasone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• dexfenfluramine

  Monitor Closely (1)dexfenfluramine and isoniazid both increase serotonin levels. Use Caution/Monitor.

• dexlansoprazole

  Monitor Closely (2)rifampin will decrease the level or effect of dexlansoprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of dexlansoprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• dextroamphetamine

  Monitor Closely (1)dextroamphetamine and isoniazid both increase serotonin levels. Use Caution/Monitor.

• dextromethorphan

  Monitor Closely (1)dextromethorphan and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• diazepam

  Monitor Closely (2)isoniazid will increase the level or effect of diazepam by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)rifampin will decrease the level or effect of diazepam by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• diazepam intranasal

  Monitor Closely (4)rifampin will decrease the level or effect of diazepam intranasal by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Strong or moderate CYP2C19 inducers may increase rate of diazepam elimination; therefore, efficacy of diazepam may be decreased.
  
  isoniazid will increase the level or effect of diazepam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.
  
  rifampin will decrease the level or effect of diazepam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inducers may increase rate of diazepam elimination; therefore, efficacy of diazepam may be decreased.
  
  isoniazid will increase the level or effect of diazepam intranasal by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Strong or moderate CYP2C19 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.

• dichlorphenamide

  Monitor Closely (1)dichlorphenamide, isoniazid. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Both drugs can cause metabolic acidosis.

• diclofenac

  Minor (1)rifampin will decrease the level or effect of diclofenac by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• didanosine

  Minor (1)didanosine, isoniazid. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Enhanced risk of peripheral neuropathy.

• dienogest/estradiol valerate

  Monitor Closely (1)isoniazid will increase the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor for potential adverse effects such as nausea, irregular uterine bleeding, breast tenderness and headache.

• digoxin

  Monitor Closely (2)rifampin will decrease the level or effect of digoxin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Reduced digoxin serum concentrations, possibly with a suboptimal therapeutic response, may be seen.
  
  rifampin decreases levels of digoxin by increasing metabolism. Use Caution/Monitor.

• dihydroergotamine

  Contraindicated (1)isoniazid will increase the level or effect of dihydroergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.Monitor Closely (1)dihydroergotamine and isoniazid both increase serotonin levels. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of dihydroergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dihydroergotamine intranasal

  Contraindicated (1)isoniazid will increase the level or effect of dihydroergotamine intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.Monitor Closely (1)dihydroergotamine intranasal and isoniazid both increase serotonin levels. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of dihydroergotamine intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• diltiazem

  Serious - Use Alternative (1)rifampin will decrease the level or effect of diltiazem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with diltiazem and strong CYP3A4 inducers However, if concomitant use is necessary, consider dosage adjustment and close monitoring of pharmacologic effects (eg, blood pressure) whenever a strong CYP3A4 inducer is added to or discontinued from therapy.

• disopyramide

  Monitor Closely (2)isoniazid will increase the level or effect of disopyramide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  rifampin will decrease the level or effect of disopyramide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• disulfiram

  Monitor Closely (2)disulfiram will increase the level or effect of isoniazid by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.
  
  isoniazid increases toxicity of disulfiram by decreasing metabolism. Use Caution/Monitor. Enhanced CNS toxicity.

• docetaxel

  Monitor Closely (3)isoniazid will increase the level or effect of docetaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  rifampin will decrease the level or effect of docetaxel by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of docetaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dolutegravir

  Serious - Use Alternative (1)rifampin will decrease the level or effect of dolutegravir by increasing metabolism. Avoid or Use Alternate Drug. Increase dolutegravir dose to 50 mg BID when coadministered with strong UGT1A/CYP3A inducers

• donepezil

  Monitor Closely (1)rifampin will decrease the level or effect of donepezil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of donepezil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• doravirine

  Contraindicated (1)rifampin will decrease the level or effect of doravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of doravirine with a strong CYP3A inducer may decrease doravirine plasma concentrations and/or effects. Potential for loss of virologic response and possible resistance to doravirine. Monitor Closely (1)isoniazid will increase the level or effect of doravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of doravirine and CYP3A4 inhibitors may increase plasma concentrations and toxicities of doravirine.

• doxepin

  Monitor Closely (1)doxepin and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• doxepin cream

  Monitor Closely (1)rifampin will decrease the level or effect of doxepin cream by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• doxorubicin

  Monitor Closely (3)rifampin will decrease the level or effect of doxorubicin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of doxorubicin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of doxorubicin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• doxorubicin liposomal

  Monitor Closely (3)rifampin will decrease the level or effect of doxorubicin liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of doxorubicin liposomal by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of doxorubicin liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dronabinol

  Monitor Closely (3)rifampin will decrease the level or effect of dronabinol by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Dronabinol is a CYP2C9 substrate.
  
  isoniazid will increase the level or effect of dronabinol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dronabinol is a CYP3A4 substrate.
  
  rifampin will decrease the level or effect of dronabinol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dronabinol is a CYP3A4 substrate.

• dronedarone

  Serious - Use Alternative (2)rifampin will decrease the level or effect of dronedarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of dronedarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• duloxetine

  Monitor Closely (2)isoniazid will increase the level or effect of duloxetine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  duloxetine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)rifampin will decrease the level or effect of duloxetine by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated.

• dutasteride

  Monitor Closely (2)rifampin will decrease the level or effect of dutasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of dutasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• duvelisib

  Monitor Closely (1)rifampin will decrease the level or effect of duvelisib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of duvelisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with a strong CYP3A inducer decreases duvelisib area under the curve (AUC), which may reduce duvelisib efficacy.

• edoxaban

  Serious - Use Alternative (1)rifampin will decrease the level or effect of edoxaban by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Avoid coadministration of edoxaban with potent P-gp inducers

• efavirenz

  Monitor Closely (3)rifampin will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• elacestrant

  Serious - Use Alternative (2)rifampin will decrease the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• elagolix

  Monitor Closely (4)isoniazid will increase the level or effect of elagolix by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of elagolix 200 mg BID with strong CYP3A inhibitors for >1 month is not recommended. Limit elagolix dose to 150 mg qDay and CYP3A inhibitor duration of use to 6 months if coadministered.
  
  elagolix will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  rifampin will increase the level or effect of elagolix by Other (see comment). Modify Therapy/Monitor Closely. Limit concomitant use of elagolix 150 mg qDay and rifampin to 6 months.
  
  rifampin will decrease the level or effect of elagolix by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Limit concomitant use of elagolix 150 mg qDay and rifampin to 6 months.

• elbasvir/grazoprevir

  Contraindicated (1)rifampin will decrease the level or effect of elbasvir/grazoprevir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. The therapeutic effect of elbasvir/grazoprevir may be reduced if coadministered with strong CYP3A inducers and is therefore contraindicated.

• eletriptan

  Monitor Closely (2)isoniazid will increase the level or effect of eletriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  eletriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of eletriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• eliglustat

  Contraindicated (2)isoniazid increases levels of eliglustat by affecting hepatic enzyme CYP2D6 metabolism. Contraindicated. If coadministered with strong or moderate CYP2D6 inhibitors, reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive and intermediate metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitors.
  
  isoniazid will increase the level or effect of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors are contraindicated with eliglustat poor or intermediate metabolizers; reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitorsMonitor Closely (1)eliglustat increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the P-gp substrate and titrate to clinical effect.Serious - Use Alternative (1)rifampin will decrease the level or effect of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A inducers significantly decreases eliglustat exposure; coadministration not recommended

• eltrombopag

  Monitor Closely (4)isoniazid will increase the level or effect of eltrombopag by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of eltrombopag by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of eltrombopag by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  eltrombopag increases levels of rifampin by decreasing metabolism. Use Caution/Monitor. OATP transporter protein inhibition.

• eluxadoline

  Monitor Closely (1)isoniazid increases levels of eluxadoline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. As a precautionary measure due to incomplete information on the metabolism of eluxadoline, use caution when coadministered with strong CYP2C19 inhibitors.Serious - Use Alternative (1)rifampin increases levels of eluxadoline by decreasing metabolism. Avoid or Use Alternate Drug. Decrease eluxadoline dose to 75 mg PO BID if coadministered with OATP1B1 inhibitors. .

• elvitegravir

  Monitor Closely (1)isoniazid increases levels of elvitegravir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Elvitegravir is a CYP3A4 substrate; if coadministered with strong CYP3A4 inhibitors may increase levels.Serious - Use Alternative (1)rifampin will decrease the level or effect of elvitegravir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid; coadministration with CYP3A inducers may result in decreased plasma concentrations of elvitegravir and/or a concomitantly administered protease inhibitor and lead to loss of therapeutic effect and to possible resistance

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  Contraindicated (1)rifampin decreases levels of elvitegravir/cobicistat/emtricitabine/tenofovir DF by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. May lead to loss of virologic response and possible resistance.Monitor Closely (1)isoniazid will increase the level or effect of elvitegravir/cobicistat/emtricitabine/tenofovir DF by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• enalapril

  Minor (1)rifampin decreases levels of enalapril by increasing metabolism. Minor/Significance Unknown.

• encorafenib

  Monitor Closely (1)encorafenib will increase the level or effect of rifampin by Other (see comment). Modify Therapy/Monitor Closely. Encorafenib (a OATP1B1 and OATP1B3 inhibitor) may increase the concentration and toxicities of OATP1B1 and OATP1B3 substrates. Closely monitor for signs and symptoms of increased exposure and consider adjusting the dose of these substrates.Serious - Use Alternative (2)isoniazid will increase the level or effect of encorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use of a strong CYP3A4 inhibitor is unavoidable, reduce encorafenib dose to one-third of the dose (eg, reduce from 450 mg/day to 150 mg/day). After discontinuing the inhibitor for 3-5 elimination half-lives, resume previous encorafenib dose.
  
  rifampin will decrease the level or effect of encorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• enfortumab vedotin

  Monitor Closely (2)isoniazid increases toxicity of enfortumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Enfortumab vedotin is an antibody-drug conjugate that releases monomethylauristatin E (MMAE) via proteolytic cleavage. MMAE is primarily metabolized by CYP3A4 in vitro. Coadministration with strong CYP3A4 inhibitors may increase free MMAE exposure, which may increase the incidence or severity of toxicities.
  
  rifampin will decrease the level or effect of enfortumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• entrectinib

  Serious - Use Alternative (2)isoniazid will increase the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of moderate CYP3A4 inhibitors with entrectinib, a CYP3A4 substrate. If coadministration unavoidable, reduce dose to 200 mg/day for patients aged 12 y or older with BSA >1.50m2. Resume previous entrectinib dose after discontinuing moderate CYP3A inhibitor for 3-5 elimination half-lives.
  
  rifampin will decrease the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• enzalutamide

  Serious - Use Alternative (1)rifampin will decrease the level or effect of enzalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider using an alternant that has no or minimal CYP3A4 induction potential when possible. If unavoidable, increase enzalutamide dose from 160 mg qDay to 240 mg qDay. If a strong CYP3A4 inducer is discontinued, return enzalutamide dose to dose used before initiating the strong CY

• eplerenone

  Monitor Closely (1)rifampin will decrease the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)isoniazid will increase the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erdafitinib

  Serious - Use Alternative (3)erdafitinib will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If coadministration unavoidable, separate administration by at least 6 hr before or after administration of P-gp substrates with narrow therapeutic index.
  
  rifampin will decrease the level or effect of erdafitinib by altering metabolism. Avoid or Use Alternate Drug. Avoid coadministration of strong CYP2C9 or CYP3A4 inducers with erdafitinib.
  
  isoniazid will increase the level or effect of erdafitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with strong CYP3A4 inhibitors, monitor closely for adverse reactions and consider decreasing dose accordingly. If strong CYP3A4 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities.

• ergotamine

  Monitor Closely (1)ergotamine and isoniazid both increase serotonin levels. Use Caution/Monitor.Serious - Use Alternative (2)rifampin will decrease the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erlotinib

  Monitor Closely (2)rifampin will decrease the level or effect of erlotinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of erlotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of erlotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin base

  Serious - Use Alternative (2)rifampin will decrease the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin ethylsuccinate

  Serious - Use Alternative (2)isoniazid will increase the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin lactobionate

  Serious - Use Alternative (2)rifampin will decrease the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin stearate

  Serious - Use Alternative (2)rifampin will decrease the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• escitalopram

  Monitor Closely (4)escitalopram and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  rifampin will decrease the level or effect of escitalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of escitalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of escitalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• esomeprazole

  Monitor Closely (2)rifampin will decrease the level or effect of esomeprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of esomeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)isoniazid will increase the level or effect of esomeprazole by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.

• estradiol

  Monitor Closely (1)rifampin will decrease the level or effect of estradiol by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)isoniazid will increase the level or effect of estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• estradiol vaginal

  Monitor Closely (2)isoniazid will increase the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase plasma concentrations of estrogens and toxicities.
  
  rifampin will decrease the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• estrogens conjugated synthetic

  Monitor Closely (1)rifampin will decrease the level or effect of estrogens conjugated synthetic by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)isoniazid will increase the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• estrogens esterified

  Monitor Closely (1)rifampin will decrease the level or effect of estrogens esterified by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of estrogens esterified by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• estropipate

  Monitor Closely (1)rifampin will decrease the level or effect of estropipate by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of estropipate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)isoniazid will increase the level or effect of estropipate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• eszopiclone

  Monitor Closely (1)rifampin will decrease the level or effect of eszopiclone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. According to prescribing information, zopiclone AUC was decreased 80% by concomitant use of rifampin. A similar effect would be expected with eszopiclone (S-enantiomer of zopiclone).

• ethanol

  Monitor Closely (1)isoniazid will increase the level or effect of ethanol by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor. Generally avoid; increased risk of hepatotoxicityMinor (2)isoniazid increases toxicity of ethanol by decreasing metabolism. Minor/Significance Unknown. Enhanced hepatotoxicity.
  
  ethanol decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Interaction more likely with chronic EtOH use.

• ethinylestradiol

  Serious - Use Alternative (1)rifampin will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.

• ethionamide

  Monitor Closely (1)ethionamide increases levels of isoniazid by unspecified interaction mechanism. Use Caution/Monitor.

• ethosuximide

  Monitor Closely (1)rifampin will decrease the level or effect of ethosuximide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• ethotoin

  Monitor Closely (1)rifampin will decrease the level or effect of ethotoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.Minor (1)isoniazid increases levels of ethotoin by decreasing metabolism. Minor/Significance Unknown.

• etonogestrel

  Monitor Closely (1)isoniazid will increase the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• etoposide

  Monitor Closely (3)isoniazid will increase the level or effect of etoposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of etoposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of etoposide by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• etravirine

  Contraindicated (1)rifampin decreases levels of etravirine by increasing metabolism. Contraindicated.Monitor Closely (3)isoniazid will increase the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of etravirine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of etravirine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)isoniazid will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• eucalyptus

  Monitor Closely (1)rifampin will decrease the level or effect of eucalyptus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of eucalyptus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• everolimus

  Serious - Use Alternative (3)isoniazid will increase the level or effect of everolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of everolimus by P-glycoprotein (MDR1) efflux transporter. Contraindicated.
  
  rifampin will decrease the level or effect of everolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• exemestane

  Monitor Closely (1)rifampin will decrease the level or effect of exemestane by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. For patients receiving exemestane with a potent CYP3A4 inducer the recommended dose of exemestane is 50 mg daily after a meal.

• fedratinib

  Serious - Use Alternative (3)isoniazid will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.
  
  rifampin will decrease the level or effect of fedratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Effect of coadministering a strong CYP3A4 inducer with fedratinib has not been studied.
  
  isoniazid will increase the level or effect of fedratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• felbamate

  Serious - Use Alternative (1)rifampin will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• felodipine

  Monitor Closely (1)isoniazid will increase the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fenfluramine

  Monitor Closely (2)rifampin will decrease the level or effect of fenfluramine by Other (see comment). Modify Therapy/Monitor Closely. Coadministration with drugs that increase serotonin may increase the risk of serotonin syndrome.
  
  fenfluramine and isoniazid both increase serotonin levels. Use Caution/Monitor.

• fentanyl

  Monitor Closely (1)rifampin will decrease the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead to a decrease in fentanyl plasma concentrations, lack of efficacy or, possibly, development of a withdrawal syndrome in a patient who has developed physical dependence to fentanyl. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase which could increase or prolong both the therapeutic and adverse effects.Serious - Use Alternative (1)isoniazid will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl intranasal

  Monitor Closely (1)rifampin will decrease the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead to a decrease in fentanyl plasma concentrations, lack of efficacy or, possibly, development of a withdrawal syndrome in a patient who has developed physical dependence to fentanyl. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase which could increase or prolong both the therapeutic and adverse effects.Serious - Use Alternative (1)isoniazid will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl transdermal

  Monitor Closely (1)rifampin will decrease the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead to a decrease in fentanyl plasma concentrations, lack of efficacy or, possibly, development of a withdrawal syndrome in a patient who has developed physical dependence to fentanyl. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase which could increase or prolong both the therapeutic and adverse effects.Serious - Use Alternative (1)isoniazid will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl transmucosal

  Monitor Closely (1)rifampin will decrease the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead to a decrease in fentanyl plasma concentrations, lack of efficacy or, possibly, development of a withdrawal syndrome in a patient who has developed physical dependence to fentanyl. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase which could increase or prolong both the therapeutic and adverse effects.Serious - Use Alternative (1)isoniazid will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fesoterodine

  Monitor Closely (1)isoniazid will increase the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fexinidazole

  Serious - Use Alternative (3)rifampin will increase the level or effect of fexinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP450 inducers may significantly increase plasma concentrations of fexinidazole?s active metabolites: fexinidazole sulfoxide (M1) and fexinidazole sulfone (M2). M2 plasma concentrations associated with increased QT prolongation risks.
  
  isoniazid will decrease the level or effect of fexinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration, monitor fexinidazole for decreased efficacy owing to decreased plasma concentrations of active M1 and M2 metabolites.
  
  fexinidazole will decrease the level or effect of rifampin by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug. Coadministration may decrease plasma concentrations of CYP2B6 substrates owing to fexinidazole inducing CYP2B6.

• fexofenadine

  Minor (1)rifampin will decrease the level or effect of fexofenadine by P-glycoprotein (MDR1) efflux transporter. Minor/Significance Unknown.

• fezolinetant

  Contraindicated (1)isoniazid will increase the level or effect of fezolinetant by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Fezolinetant AUC and peak plasma concentration are increased if coadministered with drugs that are weak, moderate, or strong CYP1A2 inhibitors

• finasteride

  Monitor Closely (2)rifampin will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• finerenone

  Monitor Closely (1)isoniazid will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor serum potassium during initiation and dosage adjustment of either finererone or moderate CYP3A4 inhibitors. Adjust finererone dosage as needed.Serious - Use Alternative (1)rifampin will decrease the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• flibanserin

  Contraindicated (1)isoniazid will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of flibanserin with moderate or strong CYP3A4 inhibitors is contraindicated. Severe hypotension or syncope can occur.Monitor Closely (2)rifampin will decrease the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inducers substantially decrease flibanserin systemic exposure.
  
  isoniazid will increase the level or effect of flibanserin by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Coadministration of flibanserin with strong CYP2C19 inhibitors may increase flibanserin exposure and increase the risk of hypotension, syncope, and CNS depression.

• fluconazole

  Monitor Closely (1)rifampin decreases levels of fluconazole by increasing metabolism. Use Caution/Monitor.Minor (1)fluconazole decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Only applies to oral preparations of both agents.

• fludrocortisone

  Monitor Closely (2)rifampin will decrease the level or effect of fludrocortisone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of fludrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of fludrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)fludrocortisone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• fluoxetine

  Monitor Closely (1)fluoxetine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• flurazepam

  Monitor Closely (1)rifampin will decrease the level or effect of flurazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• flurbiprofen

  Minor (1)rifampin will decrease the level or effect of flurbiprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• fluticasone furoate

  Monitor Closely (1)isoniazid will increase the level or effect of fluticasone furoate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inhibitors may increase fluticasone systemic exposure

• fluticasone inhaled

  Monitor Closely (1)isoniazid will increase the level or effect of fluticasone inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inhibitors may increase fluticasone systemic exposure

• fluticasone intranasal

  Serious - Use Alternative (1)isoniazid will increase the level or effect of fluticasone intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors may increase systemic corticosteroid adverse effects; monitor for signs/symptoms of high corticosteroid concentrations including Cushing type signs/symptoms.

• fluvastatin

  Monitor Closely (1)rifampin increases toxicity of fluvastatin by Other (see comment). Use Caution/Monitor. Comment: OATP1B1 inhibitors may increase risk of myopathy.Minor (2)rifampin will decrease the level or effect of fluvastatin by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
  
  rifampin decreases levels of fluvastatin by increasing metabolism. Minor/Significance Unknown.

• fluvoxamine

  Monitor Closely (1)fluvoxamine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• food

  Minor (1)food decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• fosamprenavir

  Contraindicated (1)rifampin decreases levels of fosamprenavir by increasing metabolism. Contraindicated. Contraindicated. May result in loss of antiviral efficacy and/or development of viral resistance.Monitor Closely (1)isoniazid will increase the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• fosaprepitant

  Monitor Closely (1)isoniazid will increase the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fosinopril

  Minor (1)rifampin decreases levels of fosinopril by increasing metabolism. Minor/Significance Unknown.

• fosphenytoin

  Monitor Closely (1)rifampin will decrease the level or effect of fosphenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.Minor (1)isoniazid increases levels of fosphenytoin by decreasing metabolism. Minor/Significance Unknown.

• fostamatinib

  Monitor Closely (1)fostamatinib will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Concomitant use of fostamatinib may increase concentrations of P-gp substrates. Monitor for toxicities of the P-gp substrate drug that may require dosage reduction when given concurrently with fostamatinib.Serious - Use Alternative (1)rifampin will decrease the level or effect of fostamatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fostemsavir

  Contraindicated (1)rifampin will decrease the level or effect of fostemsavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of fostemsavir (prodrug) with strong CYP3A4 inducers significantly decreases temsavir (active moiety) plasma concentrations, which may lead to loss of virologic response and resistance.

• frovatriptan

  Monitor Closely (2)isoniazid will increase the level or effect of frovatriptan by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  frovatriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.Minor (1)rifampin will decrease the level or effect of frovatriptan by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

• futibatinib

  Serious - Use Alternative (1)rifampin will decrease the level or effect of futibatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of futibatinib with drugs that are dual P-gp and strong CYP3A inducers may decrease futibatinib efficacy.

• galantamine

  Monitor Closely (2)rifampin will decrease the level or effect of galantamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of galantamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ganaxolone

  Serious - Use Alternative (1)rifampin will decrease the level or effect of ganaxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ganaxolone with moderate or strong CYP3A4 inducers. If coadministration unavoidable, consider increasing ganaxolone dose; however, do not exceed maximum daily dose for weight.Minor (1)isoniazid, ganaxolone. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. Changes in ganaxolone exposures when coadministered with strong, moderate, or weak CYP3A4 inhibitors are not expected to be clinically significant.

• gefitinib

  Monitor Closely (2)rifampin will decrease the level or effect of gefitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase gefitinib to 500 mg daily if coadministered with a strong CYP3A4 inducer. Resume gefitinib dose at 250 mg/day 7 days after discontinuing the strong inducer.
  
  isoniazid increases levels of gefitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of strong CYP3A4 inhibitors may increase risk for gefitinib adverse effects.

• gentamicin

  Monitor Closely (1)rifampin will decrease the level or effect of gentamicin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• gilteritinib

  Serious - Use Alternative (2)rifampin will decrease the level or effect of gilteritinib by Other (see comment). Avoid or Use Alternate Drug. Gilteritinib is a P-gp and CYP3A4 substrates. Coadministration of gilteritinib with a combined P-gp and strong CYP3A inducer decreases gilteritinib exposure and efficacy.
  
  isoniazid will increase the level or effect of gilteritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternatives to any strong CYP3A4 inhibitor when coadministered with gilteritinib. If such a combination cannot be avoided, closely monitor for gilteritinib-related adverse effects. Interrupt and reduce gilteritinib dosage in patients with serious or life-threatening toxicity.

• glasdegib

  Serious - Use Alternative (2)rifampin will decrease the level or effect of glasdegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of glasdegib with strong CYP3A inducers.
  
  isoniazid will increase the level or effect of glasdegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternate therapies that are not strong CYP3A inhibitors or monitor for increased risk of adverse effects, including QTc interval prolongation.

• glecaprevir/pibrentasvir

  Contraindicated (1)rifampin will decrease the level or effect of glecaprevir/pibrentasvir by increasing metabolism. Contraindicated. Coadministration of rifampin (a strong CYP3A4 and P-gp inducer) with glecaprevir/pibrentasvir significantly decreased glecaprevir/pibrentasvir plasma concentrations and AUC. Potential for loss of therapeutic effect.Monitor Closely (1)isoniazid will increase the level or effect of glecaprevir/pibrentasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of glecaprevir/pibrentasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• glimepiride

  Monitor Closely (1)rifampin decreases levels of glimepiride by increasing metabolism. Use Caution/Monitor.Minor (1)isoniazid decreases effects of glimepiride by unspecified interaction mechanism. Minor/Significance Unknown.

• glipizide

  Monitor Closely (1)rifampin decreases levels of glipizide by increasing metabolism. Use Caution/Monitor.Minor (1)isoniazid decreases effects of glipizide by unspecified interaction mechanism. Minor/Significance Unknown.

• glyburide

  Monitor Closely (2)rifampin decreases levels of glyburide by increasing metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of glyburide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. Strong CYP2C9 inducers may increase glyburide metabolism.Minor (1)isoniazid decreases effects of glyburide by unspecified interaction mechanism. Minor/Significance Unknown.

• green tea

  Monitor Closely (1)green tea, isoniazid. Other (see comment). Use Caution/Monitor. Comment: Avoid combination or excessive consumption of green tea. Combination may increase risk of cardiac arrhythmias or severe hypertension can occur due to caffeine component of green tea.

• guanfacine

  Monitor Closely (2)isoniazid will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available.
  
  rifampin will decrease the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inducers significantly reduce guanfacine plasma concentrations and elimination half-life. If coadministered, more frequent dosing of the IR product may be required to achieve or maintain the desired hypotensive response. For patients with ADHD, FDA-approved labeling for ER guanfacine recommends that, if coadministered, doubling the recommended dose of guanfacine should be considered.

• haloperidol

  Monitor Closely (2)rifampin will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  isoniazid will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• hydrocodone

  Monitor Closely (2)rifampin will decrease the level or effect of hydrocodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Caution when discontinuing CYP3A4 inducers that are coadministered with hydrocodone; plasma concentrations of hydrocodone may increase and can result in potentially fatal respiratory depression
  
  isoniazid will increase the level or effect of hydrocodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with CYP3A4 inhibitors may increase hydrocodone plasma concentrations and can result in potentially fatal respiratory depression

• hydrocortisone

  Monitor Closely (2)rifampin will decrease the level or effect of hydrocortisone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of hydrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of hydrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)hydrocortisone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• hydroxyprogesterone caproate (DSC)

  Monitor Closely (1)isoniazid will increase the level or effect of hydroxyprogesterone caproate (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of hydroxyprogesterone caproate (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ibrutinib

  Serious - Use Alternative (2)rifampin decreases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A inducers decrease ibrutinib plasma concentrations by ~10-fold.
  
  isoniazid increases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of ibrutinib and strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor must be used short-term (eg, anti-infectives for =7 days), interrupt ibrutinib therapy until strong CYP3A4 inhibitor is discontinued.

• ibuprofen

  Minor (1)rifampin will decrease the level or effect of ibuprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• ibuprofen IV

  Minor (1)rifampin will decrease the level or effect of ibuprofen IV by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• idelalisib

  Serious - Use Alternative (2)rifampin will decrease the level or effect of idelalisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration; strong CYP3A4 inducers significantly decrease idelalisib systemic exposure
  
  isoniazid will increase the level or effect of idelalisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministered with strong CYP3A inhibitors, monitor for signs of idelalisib toxicity; follow recommendations for dosage modifications if adverse reactions occur

• ifosfamide

  Monitor Closely (2)rifampin increases effects of ifosfamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Coadministration of ifosfamide with CYP2B6 inducers may increase metabolism of ifosfamide to its metabolite. Monitor for increased effects/toxicities if combined with CYP2B6 inducers.
  
  rifampin increases toxicity of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inducers may increase the metabolism of ifosfamide to its active alkylating metabolites. CYP3A4 inducers may increase the formation of the neurotoxic/nephrotoxic ifosfamide metabolite, chloroacetaldehyde. Closely monitor patients taking ifosfamide with CYP3A4 inducers for toxicities and consider dose adjustment.

• iloperidone

  Monitor Closely (1)isoniazid will increase the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• imatinib

  Monitor Closely (3)isoniazid will increase the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of imatinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• imidapril

  Minor (1)rifampin decreases levels of imidapril by increasing metabolism. Minor/Significance Unknown.

• imipramine

  Monitor Closely (6)rifampin will decrease the level or effect of imipramine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of imipramine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of imipramine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of imipramine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  imipramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.Minor (1)isoniazid will increase the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• indinavir

  Monitor Closely (2)isoniazid will increase the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of indinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)rifampin decreases levels of indinavir by increasing metabolism. Contraindicated.
  
  rifampin will decrease the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• infigratinib

  Contraindicated (1)isoniazid will increase the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.Serious - Use Alternative (1)rifampin will decrease the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• insulin aspart

  Minor (1)isoniazid decreases effects of insulin aspart by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin degludec

  Monitor Closely (1)isoniazid decreases effects of insulin degludec by pharmacodynamic antagonism. Use Caution/Monitor. Isoniazid may increase blood glucose (rare).

• insulin degludec/insulin aspart

  Monitor Closely (1)isoniazid decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Use Caution/Monitor. Isoniazid may increase blood glucose (rare).

• insulin detemir

  Minor (1)isoniazid decreases effects of insulin detemir by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin glargine

  Minor (1)isoniazid decreases effects of insulin glargine by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin glulisine

  Minor (1)isoniazid decreases effects of insulin glulisine by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin inhaled

  Monitor Closely (1)isoniazid decreases effects of insulin inhaled by pharmacodynamic antagonism. Use Caution/Monitor. Isoniazid may increase blood glucose (rare).

• insulin lispro

  Minor (1)isoniazid decreases effects of insulin lispro by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin NPH

  Minor (1)isoniazid decreases effects of insulin NPH by unspecified interaction mechanism. Minor/Significance Unknown.

• insulin regular human

  Minor (1)isoniazid decreases effects of insulin regular human by unspecified interaction mechanism. Minor/Significance Unknown.

• irinotecan

  Contraindicated (1)rifampin will decrease the level or effect of irinotecan by affecting hepatic enzyme CYP2B6 metabolism. Contraindicated.Monitor Closely (1)rifampin will decrease the level or effect of irinotecan by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)isoniazid will increase the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• irinotecan liposomal

  Contraindicated (1)rifampin will decrease the level or effect of irinotecan liposomal by affecting hepatic enzyme CYP2B6 metabolism. Contraindicated.Monitor Closely (1)rifampin will decrease the level or effect of irinotecan liposomal by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)isoniazid will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• isavuconazonium sulfate

  Contraindicated (1)rifampin will decrease the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.Monitor Closely (1)isoniazid will decrease the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isocarboxazid

  Serious - Use Alternative (1)isocarboxazid and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug.

• isoniazid

  Serious - Use Alternative (1)rifampin increases toxicity of isoniazid by increasing metabolism. Avoid or Use Alternate Drug. Rifampin enhances the metabolism of isoniazid to hepatotoxic metabolites.

• isosorbide dinitrate

  Minor (1)rifampin will decrease the level or effect of isosorbide dinitrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• isosorbide mononitrate

  Minor (1)rifampin will decrease the level or effect of isosorbide mononitrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• isradipine

  Monitor Closely (2)rifampin will decrease the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• istradefylline

  Monitor Closely (2)isoniazid will increase the level or effect of istradefylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Do not exceed istradefylline 20 mg/day if coadministered with strong CYP3A4 inhibitors.
  
  istradefylline will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of P-gp substrates in clinical trials. Consider dose reduction of sensitive P-gp substrates.Serious - Use Alternative (1)rifampin will decrease the level or effect of istradefylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of istradefylline with strong CYP3A4 inducers.

• itraconazole

  Monitor Closely (3)rifampin will decrease the level or effect of itraconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid decreases levels of itraconazole by unspecified interaction mechanism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of itraconazole by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• ivabradine

  Contraindicated (1)isoniazid will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of ivabradine with strong CYP3A4 inhibitors is contraindicated.Serious - Use Alternative (1)rifampin will decrease the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ivabradine with moderate CYP3A4 inducers.

• ivacaftor

  Monitor Closely (2)isoniazid will increase the level or effect of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce ivacaftor dose if coadministered with strong CYP3A4 inhibitors. See specific ivacaftor-containing product for precise dosage modification.
  
  ivacaftor increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Ivacaftor and its M1 metabolite has the potential to inhibit P-gp; may significantly increase systemic exposure to sensitive P-gp substrates with a narrow therapeutic index.Serious - Use Alternative (1)rifampin decreases levels of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with strong CYP3A4 inducers; systemic exposure of ivacaftor substantially reduced (ie, ~9-fold).

• ivermectin

  Monitor Closely (1)rifampin will decrease the level or effect of ivermectin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• ivosidenib

  Serious - Use Alternative (1)rifampin will decrease the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of ivosidenib with strong CYP3A4 inducers decreased ivosidenib plasma concentrations.

• ixabepilone

  Monitor Closely (1)isoniazid will increase the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ixazomib

  Serious - Use Alternative (1)rifampin will decrease the level or effect of ixazomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ixazomib with strong CYP3A inducers. Strong inducers have been shown to decrease ixazomib Cmax by 54% and AUC by 74%.Minor (1)isoniazid, ixazomib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. In clinical trials, coadministration of ixazomib with strong CYP3A inhibitors did not result in a clinically meaningful change in the systemic exposure of ixazomib.

• ketamine

  Monitor Closely (2)rifampin will decrease the level or effect of ketamine by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of ketamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ketoconazole

  Contraindicated (1)isoniazid decreases levels of ketoconazole by unspecified interaction mechanism. Contraindicated.Monitor Closely (1)rifampin will decrease the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (2)ketoconazole decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Only applies to oral preparations of both agents.
  
  isoniazid will increase the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• L-tryptophan

  Monitor Closely (1)isoniazid and L-tryptophan both increase serotonin levels. Use Caution/Monitor.

• lacosamide

  Monitor Closely (1)isoniazid increases levels of lacosamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider decreasing lacosamide dose when coadministered with strong CYP3A4 inhibitors.

• lamotrigine

  Monitor Closely (2)rifampin decreases levels of lamotrigine by increasing metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of lamotrigine by increasing hepatic clearance. Use Caution/Monitor.

• lansoprazole

  Monitor Closely (1)isoniazid will increase the level or effect of lansoprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of lansoprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)rifampin will decrease the level or effect of lansoprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• lapatinib

  Monitor Closely (2)rifampin will decrease the level or effect of lapatinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• larotrectinib

  Serious - Use Alternative (1)rifampin will decrease the level or effect of larotrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of larotrectinib with strong CYP3A4 inducers is unavoidable, double larotrectinib dose. Resume prior larotrectinib dose once CYP3A4 inducer discontinued for 3-5 half-lives

• lasmiditan

  Serious - Use Alternative (1)lasmiditan increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• ledipasvir/sofosbuvir

  Contraindicated (1)rifampin will decrease the level or effect of ledipasvir/sofosbuvir by P-glycoprotein (MDR1) efflux transporter. Contraindicated. P-gp inducers decrease sofosbuvir levels, and therefore decrease conversion to sofosbuvir's active metabolite (GS-331007) responsible for 90% of pharmacologic effect

• lefamulin

  Serious - Use Alternative (2)rifampin will decrease the level or effect of lefamulin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lefamulin with strong or moderate CYP3A inducers unless the benefit outweighs risks. Monitor for reduced efficacy.
  
  isoniazid will increase the level or effect of lefamulin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lefamulin with strong CYP3A inhibitors.

• leflunomide

  Minor (1)rifampin increases effects of leflunomide by increasing metabolism. Minor/Significance Unknown. Leflunomide's effects due to its active metabolite.

• lemborexant

  Monitor Closely (1)lemborexant will decrease the level or effect of rifampin by affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Monitor CYP2B6 substrate for adequate clinical response. Consider increasing the CYP2B6 substrate dose according to specific prescribing recommendations.Serious - Use Alternative (2)isoniazid will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lemborexant with moderate or strong CYP3A inhibitors.
  
  rifampin will decrease the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lenacapavir

  Contraindicated (1)rifampin will decrease the level or effect of lenacapavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of lenacapavir with strong CYP3A inducers is contraindicated.

• leniolisib

  Serious - Use Alternative (1)rifampin will decrease the level or effect of leniolisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lesinurad

  Monitor Closely (1)rifampin will decrease the level or effect of lesinurad by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely.

• letermovir

  Serious - Use Alternative (2)rifampin will decrease the level or effect of letermovir by Other (see comment). Avoid or Use Alternate Drug. Coadministration of letermovir with UCT1A1/3 inducers is not recommended.
  
  rifampin will decrease the level or effect of letermovir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Coadministration of letermovir with P-gp inducers is not recommended.

• levamlodipine

  Monitor Closely (2)rifampin will decrease the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  isoniazid will increase the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate and strong CYP3A inhibitors results in increased systemic exposure to amlodipine and may require dose reduction. Monitor for symptoms of hypotension and edema when amlodipine is coadministered with CYP3A inhibitors to determine the need for dose adjustment.

• levodopa inhaled

  Monitor Closely (1)isoniazid decreases effects of levodopa inhaled by altering metabolism. Use Caution/Monitor. Isoniazid may inhibit dopa-decarboxylase in the brain; thereby, preventing conversion of levodopa to active dopamine.

• levoketoconazole

  Contraindicated (1)isoniazid decreases levels of levoketoconazole by unspecified interaction mechanism. Contraindicated.Monitor Closely (1)rifampin will decrease the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (2)isoniazid will increase the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  levoketoconazole decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Only applies to oral preparations of both agents.

• levomilnacipran

  Monitor Closely (2)levomilnacipran and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  isoniazid will increase the level or effect of levomilnacipran by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Do not exceed 80 mg/day of levomilnacipran when coadministered with strong CYP3A4 inhibitors

• levonorgestrel intrauterine

  Monitor Closely (1)rifampin decreases levels of levonorgestrel intrauterine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• levonorgestrel oral

  Monitor Closely (1)rifampin decreases levels of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  Monitor Closely (2)isoniazid will increase the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase the plasma hormone concentrations. Use of a nonhormonal contraceptive is recommended.
  
  rifampin will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.

• levothyroxine

  Minor (1)rifampin decreases levels of levothyroxine by increasing metabolism. Minor/Significance Unknown.

• lidocaine

  Monitor Closely (2)isoniazid will increase the level or effect of lidocaine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of lidocaine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• linagliptin

  Monitor Closely (2)rifampin will decrease the level or effect of linagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of alternative treatments is strongly recommended when linagliptin is to be administered with a CYP3A4 inducer.
  
  rifampin will decrease the level or effect of linagliptin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Use of alternative treatments is strongly recommended when linagliptin is to be administered with a P-gp inducer.

• linezolid

  Serious - Use Alternative (1)linezolid and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug. Linezolid may increase serotonin as a result of MAO-A inhibition. If linezolid must be administered, discontinue serotonergic drug immediately and monitor for CNS toxicity. Serotonergic therapy may be resumed 24 hours after last linezolid dose or after 2 weeks of monitoring, whichever comes first.

• liothyronine

  Minor (1)rifampin decreases levels of liothyronine by increasing metabolism. Minor/Significance Unknown.

• lisinopril

  Minor (1)rifampin decreases levels of lisinopril by increasing metabolism. Minor/Significance Unknown.

• lithium

  Monitor Closely (1)isoniazid and lithium both increase serotonin levels. Use Caution/Monitor.

• lofepramine

  Monitor Closely (2)lofepramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  rifampin decreases levels of lofepramine by increasing metabolism. Use Caution/Monitor.

• lomitapide

  Contraindicated (1)isoniazid increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Increases lomitapide levels several folds.Monitor Closely (1)lomitapide increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing dose when used concomitantly with lomitapide.Serious - Use Alternative (1)rifampin will decrease the level or effect of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lonafarnib

  Contraindicated (2)rifampin will decrease the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lonafarnib is a sensitive CYP3A4 substrate. Coadministration with strong or moderate CYP3A4 inducers is contraindicated.
  
  isoniazid will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lonafarnib is a sensitive CYP3A4 substrate. Coadministration with strong or moderate CYP3A4 inhibitors is contraindicated.

• loperamide

  Monitor Closely (1)rifampin will decrease the level or effect of loperamide by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• lopinavir

  Monitor Closely (1)isoniazid will increase the level or effect of lopinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of lopinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• loratadine

  Monitor Closely (1)isoniazid will increase the level or effect of loratadine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of loratadine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)rifampin will decrease the level or effect of loratadine by P-glycoprotein (MDR1) efflux transporter. Minor/Significance Unknown.

• lorcaserin

  Serious - Use Alternative (1)isoniazid and lorcaserin both increase serotonin levels. Avoid or Use Alternate Drug.

• lorlatinib

  Contraindicated (1)rifampin will decrease the level or effect of lorlatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of lorlatinib with strong CYP3A inducers is contraindicated. Discontinue the strong CYP3A inducer for 3 plasma half-lives before initiating lorlatinib.Serious - Use Alternative (1)isoniazid will increase the level or effect of lorlatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministering lorlatinib with strong CYP3A inhibitors. If unavoidable, reduce lorlatinib dose by 25 mg/day. If strong CYP3A inhibitor discontinued, increase to previous lorlatinib (dose after 3 plasma half-lives of strong CYP3A inhibitor). See monograph for further details.

• losartan

  Monitor Closely (2)rifampin will decrease the level or effect of losartan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of losartan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lovastatin

  Contraindicated (1)isoniazid will increase the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors increase systemic statin exposure and risk of myopathy, including rhabdomyolysisMonitor Closely (1)rifampin will decrease the level or effect of lovastatin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lsd

  Monitor Closely (1)isoniazid and lsd both increase serotonin levels. Use Caution/Monitor.

• lumacaftor/ivacaftor

  Contraindicated (1)rifampin will decrease the level or effect of lumacaftor/ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A inducers have minimal effect on lumacaftor exposure, but decreased ivacaftor exposure (AUC) by 57%. This may reduce the effectiveness of lumacaftor/ivacaftor. Therefore, coadministration is not recommended.Monitor Closely (2)lumacaftor/ivacaftor, rifampin. affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2B6 substrates. .
  
  isoniazid increases levels of lumacaftor/ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A inhibitors do not impact lumacaftor exposure, but increased ivacaftor exposure by 4.3-fold. Due to the induction effect of lumacaftor on CYP3A, at steady-state the net exposure of ivacaftor is not expected to exceed that when given in the absence of lumacaftor at a dose of 150 mg q12hr (the approved dose of ivacaftor monotherapy). Therefore, no dose adjustment is necessary when CYP3A inhibitors are initiated in patients currently taking lumacaftor/ivacaftor. However, when initiating lumacaftor/ivacaftor in patients taking strong CYP3A inhibitors, reduce the dose to 1 tablet daily (lumacaftor 200 mg/ivacaftor 125 mg total daily dose) for the first week of treatment to allow for the steady-state induction effect of lumacaftor. Following this period, continue with the recommended daily dose. No dose adjustment is required for moderate or weak CYP3A4 inhibitors.

• lumateperone

  Monitor Closely (1)isoniazid will increase the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce lumateperone dose to 21 mg/day if coadministered with moderate CYP3A4 inhibitors.Serious - Use Alternative (1)rifampin will decrease the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lumefantrine

  Contraindicated (1)rifampin will decrease the level or effect of lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration with strong CYP3A4 inducers can result in decreased serum concentrations and loss of antimalarial efficacyMonitor Closely (1)isoniazid will increase the level or effect of lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lurasidone

  Contraindicated (2)isoniazid will increase the level or effect of lurasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of lurasidone and strong CYP3A4 inhibitors is contraindicated.
  
  rifampin decreases levels of lurasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of lurasidone with strong CYP3A4 inducers is contraindicated.

• lurbinectedin

  Serious - Use Alternative (2)isoniazid will increase the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• macimorelin

  Serious - Use Alternative (1)rifampin will decrease the level or effect of macimorelin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Potential for false positive test results if macimorelin and strong CYP3A4 inducers are coadministered. Discontinue strong CYP3A4 inducer, allowing for sufficient washout time, before testing.

• macitentan

  Serious - Use Alternative (2)rifampin will decrease the level or effect of macitentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministering macitentan with strong CYP3A4 inducers
  
  isoniazid will increase the level or effect of macitentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministering macitentan with strong CYP3A4 inhibitors

• maprotiline

  Monitor Closely (1)maprotiline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• maraviroc

  Monitor Closely (2)rifampin will decrease the level or effect of maraviroc by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of maraviroc by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Decrease maraviroc dose to 150 mg BID when coadministered with strong CYP3A4 inhibitorsSerious - Use Alternative (1)rifampin will decrease the level or effect of maraviroc by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• marijuana

  Monitor Closely (1)rifampin will decrease the level or effect of marijuana by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• mavacamten

  Contraindicated (3)rifampin will decrease the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated.
  
  rifampin will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  isoniazid will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Contraindicated. Strong or moderate CYP2C19 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction. Monitor Closely (1)isoniazid will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Inititiation of moderate CYP3A4 inhibitors may require decreased mavacamten dose.

• medroxyprogesterone

  Monitor Closely (2)isoniazid will increase the level or effect of medroxyprogesterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of medroxyprogesterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Contraceptirve failure possible

• mefloquine

  Monitor Closely (2)isoniazid will increase the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• meloxicam

  Minor (2)rifampin will decrease the level or effect of meloxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
  
  rifampin decreases levels of meloxicam by increasing metabolism. Minor/Significance Unknown.

• meperidine

  Monitor Closely (1)isoniazid and meperidine both increase serotonin levels. Modify Therapy/Monitor Closely.

• mestranol

  Monitor Closely (1)rifampin will decrease the level or effect of mestranol by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)rifampin decreases levels of mestranol by increasing metabolism. Avoid or Use Alternate Drug. May result in contraceptive failure.
  
  rifampin will decrease the level or effect of mestranol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)isoniazid will increase the level or effect of mestranol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• metformin

  Monitor Closely (1)isoniazid decreases effects of metformin by unspecified interaction mechanism. Use Caution/Monitor. Patient should be closely observed for loss of blood glucose control; when drugs are withdrawn from a patient receiving metformin, patient should be observed closely for hypoglycemia.

• methadone

  Monitor Closely (2)isoniazid will increase the level or effect of methadone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of methadone by increasing metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of methadone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• methylene blue

  Serious - Use Alternative (1)methylene blue and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug. Methylene blue and isoniazid may increase serotonin as a result of MAO-A inhibition. If methylene blue must be administered, discontinue isoniazid immediately and monitor for CNS toxicity. Isoniazid may be resumed 24 hours after last methylene blue dose or after 2 weeks of monitoring, whichever comes first.

• methylprednisolone

  Monitor Closely (2)rifampin will decrease the level or effect of methylprednisolone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of methylprednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of methylprednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)methylprednisolone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• metoprolol

  Monitor Closely (1)rifampin decreases levels of metoprolol by increasing metabolism. Use Caution/Monitor.

• metronidazole

  Monitor Closely (1)metronidazole will increase the level or effect of isoniazid by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.

• mexiletine

  Monitor Closely (2)isoniazid will increase the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of mexiletine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• miconazole vaginal

  Monitor Closely (1)rifampin decreases levels of miconazole vaginal by increasing metabolism. Use Caution/Monitor.Minor (1)miconazole vaginal decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Only applies to oral preparations of both agents.

• midazolam

  Monitor Closely (1)isoniazid will increase the level or effect of midazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of midazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• midazolam intranasal

  Serious - Use Alternative (1)isoniazid will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of moderate CYP3A4 inhibitors with midazolam intranasal causes higher midazolam systemic exposure, which may prolong sedation.

• midostaurin

  Serious - Use Alternative (2)rifampin will decrease the level or effect of midostaurin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inducers may decrease midostaurin concentrations resulting in reduced efficacy.
  
  isoniazid will increase the level or effect of midostaurin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong CYP3A4 inhibitors cannot be avoided, monitor midostaurin for increased risk of adverse reactions, especially during the first week of treatment.

• mifepristone

  Monitor Closely (1)rifampin will decrease the level or effect of mifepristone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inducers have not been studied, coadministration not recommended by manufacturer

• miglitol

  Minor (1)isoniazid decreases effects of miglitol by unspecified interaction mechanism. Minor/Significance Unknown.

• milnacipran

  Monitor Closely (1)milnacipran and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• mipomersen

  Monitor Closely (2)mipomersen, rifampin. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.
  
  mipomersen, isoniazid. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.

• mirtazapine

  Monitor Closely (2)isoniazid and mirtazapine both increase serotonin levels. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of mirtazapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)isoniazid will increase the level or effect of mirtazapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• mobocertinib

  Serious - Use Alternative (1)isoniazid will increase the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If use of moderate CYP3A4 inhibitor unavoidable, reduce mobocertinib dose by ~50% (eg, 160 to 80 mg); closely monitor QTc interval.

• modafinil

  Minor (1)rifampin will decrease the level or effect of modafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• moexipril

  Minor (1)rifampin decreases levels of moexipril by increasing metabolism. Minor/Significance Unknown.

• montelukast

  Monitor Closely (1)rifampin will decrease the level or effect of montelukast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of montelukast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• morphine

  Monitor Closely (1)isoniazid and morphine both increase serotonin levels. Use Caution/Monitor.Minor (1)rifampin decreases levels of morphine by increasing metabolism. Minor/Significance Unknown.

• nafcillin

  Monitor Closely (1)nafcillin decreases effects of rifampin by pharmacodynamic antagonism. Use Caution/Monitor. Nafcillin may show antagonistic effects against S. aureus.

• naldemedine

  Monitor Closely (1)isoniazid increases levels of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with strong or moderate CYP3A4 inhibitors.Serious - Use Alternative (1)rifampin will decrease the level or effect of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with strong CYP3A4 inducers.

• naloxegol

  Contraindicated (2)rifampin will decrease the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Use of naloxegol with strong CYP3A4 inducers is not recommended
  
  isoniazid will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of naloxegol with strong CYP3A4 inhibitors can significantly increase naloxegol systemic exposure which may precipitate opioid withdrawal symptoms

• naratriptan

  Monitor Closely (1)naratriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.

• nateglinide

  Minor (1)isoniazid decreases effects of nateglinide by unspecified interaction mechanism. Minor/Significance Unknown.

• nefazodone

  Monitor Closely (2)rifampin will decrease the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nefazodone and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• nelfinavir

  Contraindicated (1)rifampin decreases levels of nelfinavir by increasing metabolism. Contraindicated. Decreased nelfinavir plasma concentrations may lead to loss of therapeutic effect and possible development of resistance to nelfinavir or other coadministered antiretroviral agents.Monitor Closely (1)isoniazid will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• neomycin PO

  Monitor Closely (1)rifampin will decrease the level or effect of neomycin PO by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• neratinib

  Serious - Use Alternative (2)rifampin will decrease the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inducers.
  
  isoniazid will increase the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inhibitors.

• netupitant/palonosetron

  Monitor Closely (1)isoniazid will increase the level or effect of netupitant/palonosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Netupitant is mainly metabolized by CYP3A4; no dosage adjustment is requiredSerious - Use Alternative (1)rifampin will decrease the level or effect of netupitant/palonosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Netupitant is mainly metabolized by CYP3A4; avoid use in patients who are chronically using a strong CYP3A4 inducer

• nevirapine

  Serious - Use Alternative (1)rifampin will decrease the level or effect of nevirapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.Minor (1)rifampin decreases levels of nevirapine by increasing metabolism. Minor/Significance Unknown.

• niacin

  Minor (1)isoniazid decreases levels of niacin by pharmacodynamic antagonism. Minor/Significance Unknown.

• nicardipine

  Monitor Closely (1)isoniazid will increase the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• nifedipine

  Monitor Closely (2)rifampin will decrease the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  isoniazid will increase the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nilotinib

  Monitor Closely (1)rifampin will decrease the level or effect of nilotinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)rifampin will decrease the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• nimodipine

  Monitor Closely (2)rifampin will decrease the level or effect of nimodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of nimodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nintedanib

  Serious - Use Alternative (1)rifampin decreases levels of nintedanib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Avoid coadministration, particularly for P-gp inducers that are also CYP3A4 inducers; nintedanib is a substrate of P-gp and to a less extent CYP3A4.

• nirmatrelvir

  Contraindicated (1)rifampin will decrease the level or effect of nirmatrelvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Nirmatrelvir, a CYP3A4 substrate, is contraindicated with strong CYP3A4 inducers. Significantly reduced nirmatrelvir plasma concentrations may be associated with potential for loss of virologic response and possible resistance. Do not initiate nirmatrelvir/ritonavir immediately after discontinuing a strong 3A4 inducer owing to time needed for systemic clearance of the inducer.

• nirmatrelvir/ritonavir

  Contraindicated (1)rifampin will decrease the level or effect of nirmatrelvir/ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Nirmatrelvir, a CYP3A4 substrate, is contraindicated with strong CYP3A4 inducers. Significantly reduced nirmatrelvir plasma concentrations may be associated with potential for loss of virologic response and possible resistance. Do not initiate nirmatrelvir/ritonavir immediately after discontinuing a strong 3A4 inducer owing to time needed for systemic clearance of the inducer.

• nisoldipine

  Serious - Use Alternative (2)rifampin will decrease the level or effect of nisoldipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of nisoldipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• nitrendipine

  Monitor Closely (2)rifampin will decrease the level or effect of nitrendipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of nitrendipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• norethindrone

  Serious - Use Alternative (2)rifampin decreases levels of norethindrone by increasing metabolism. Avoid or Use Alternate Drug. Avoid coadministration unless benefit outweighs risk. When coadministered, hormonal contraceptives are not a reliable method of effective birth control. Concomitant use may increase incidence of menstruation associated adverse effects (amenorrhea, dysmenorrhea, menorrhagia).
  
  rifampin will decrease the level or effect of norethindrone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use of nonhormonal contraceptives advised

• norethindrone acetate

  Serious - Use Alternative (1)rifampin decreases levels of norethindrone acetate by increasing metabolism. Avoid or Use Alternate Drug. Avoid coadministration unless benefit outweighs risk. When coadministered, hormonal contraceptives are not a reliable method of effective birth control. Concomitant use may increase incidence of menstruation associated adverse effects (amenorrhea, dysmenorrhea, menorrhagia).

• norethindrone transdermal

  Serious - Use Alternative (1)rifampin will decrease the level or effect of norethindrone transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration unless benefit outweighs risk. When coadministered, hormonal contraceptives are not a reliable method of effective birth control. Concomitant use may increase incidence of menstruation associated adverse effects (amenorrhea, dysmenorrhea, menorrhagia).

• norgestrel

  Monitor Closely (1)rifampin will decrease the level or effect of norgestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of nonhormonal contraceptives advised

• nortriptyline

  Monitor Closely (1)nortriptyline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.Minor (1)rifampin decreases levels of nortriptyline by increasing metabolism. Minor/Significance Unknown.

• olanzapine

  Monitor Closely (2)isoniazid will increase the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of olanzapine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• olaparib

  Serious - Use Alternative (2)rifampin will decrease the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of olaparib with strong CYP3A4 inducers.
  
  isoniazid will increase the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong CYP3A inhibitors cannot be avoided, reduce olaparib dose to 150 mg (capsule) or 100 mg (tablet) PO BID. Do not substitute tablets with capsules.

• oliceridine

  Monitor Closely (3)isoniazid will increase the level or effect of oliceridine by affecting hepatic enzyme CYP2D6 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.
  
  rifampin will decrease the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. If coadministration with a CYP3A4 inducer is necessary, consider increasing oliceridine dose until stable drug effects are achieved; monitor for signs of opioid withdrawal. If inducer is discontinued, consider oliceridine dosage reduction and monitor for signs of respiratory depression.
  
  isoniazid will increase the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.

• olutasidenib

  Serious - Use Alternative (1)rifampin will decrease the level or effect of olutasidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong or moderate CYP3A inducers decrease olutasidenib (a CYP3A4 substrate) plasma concentrations and efficacy.

• omaveloxolone

  Serious - Use Alternative (2)isoniazid will increase the level or effect of omaveloxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unavoidable, reduce omaveloxolone dose to 100 mg/day. Closely monitor for adverse effects. If adverse effects emerge, further reduce to 50 mg/day.
  
  rifampin will decrease the level or effect of omaveloxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)

  Contraindicated (2)rifampin will decrease the level or effect of ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) by increasing metabolism. Contraindicated. Strong CYP2C8 inducers may reduce dasabuvir levels, and therefore decreased efficacy of Viekira Pak
  
  rifampin will decrease the level or effect of ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inducers may reduce partiaprevir and ritonavir levels, and therefore decreased efficacy of Viekira Pak

• omeprazole

  Monitor Closely (1)rifampin will decrease the level or effect of omeprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)rifampin will decrease the level or effect of omeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of omeprazole by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug.

• ondansetron

  Monitor Closely (3)isoniazid will increase the level or effect of ondansetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP-450 inhibitors may decrease clearance of ondansetron. However, no dosage adjustment for ondansetron is recommended
  
  rifampin will decrease the level or effect of ondansetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of ondansetron by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. CYP-450 inhibitors may decrease clearance of ondansetron. However, no dosage adjustment for ondansetron is recommendedMinor (1)rifampin will decrease the level or effect of ondansetron by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

• opium tincture

  Minor (1)rifampin decreases levels of opium tincture by increasing metabolism. Minor/Significance Unknown.

• osilodrostat

  Monitor Closely (3)rifampin will decrease the level or effect of osilodrostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of osilodrostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce dose of osilodrostat, a CYP3A4 substrate, by half when coadministered with a strong CYP3A4 inhibitor.
  
  rifampin will decrease the level or effect of osilodrostat by Other (see comment). Use Caution/Monitor. Osilodrostat is a CYP3A4 and CYP2B6 subtrate. Monitor cortisol concentration and patient?s signs and symptoms during coadministration and discontinuation with strong CYP3A4 and/or CYP2B6 inducers. Adjust dose of osilodrostat if necessary.

• osimertinib

  Serious - Use Alternative (2)isoniazid will increase the level or effect of osimertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of osimertinib with strong CYP3A4 inhibitors. If no other alternative treatment exists, monitor patient more closely for adverse effects.
  
  rifampin will decrease the level or effect of osimertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of osimertinib with strong CYP3A inducers.

• ospemifene

  Monitor Closely (5)rifampin decreases levels of ospemifene by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of ospemifene by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  isoniazid increases levels of ospemifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid increases levels of ospemifene by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of ospemifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• oxacillin

  Minor (1)rifampin decreases levels of oxacillin by increasing metabolism. Minor/Significance Unknown.

• oxybutynin

  Monitor Closely (1)rifampin will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• oxycodone

  Monitor Closely (1)rifampin decreases levels of oxycodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)isoniazid increases levels of oxycodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Oxycodone dose reduction may be warranted when coadministered with strong CYP3A4 inhibitors.

• ozanimod

  Serious - Use Alternative (1)rifampin will decrease the level or effect of ozanimod by Other (see comment). Avoid or Use Alternate Drug. Coadministration of ozanimod (a CYP2C8 substrate) with strong CYP2C8 inducers decreases the exposure of the active metabolites (CC112273 and CC1084037) of ozanimod, which may decrease the effiicacy of ozanimod. Therefore, coadministration of ozanimod with strong CYP2C8 inducers is not recommended.

• paclitaxel

  Monitor Closely (4)isoniazid will increase the level or effect of paclitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of paclitaxel by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of paclitaxel by Other (see comment). Use Caution/Monitor. Paclitaxel levels/efficacy may decrease when coadministered with CYP2C8 inducers
  
  rifampin will decrease the level or effect of paclitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• paclitaxel protein bound

  Monitor Closely (4)rifampin will decrease the level or effect of paclitaxel protein bound by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of paclitaxel protein bound by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of paclitaxel protein bound by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of paclitaxel protein bound by Other (see comment). Use Caution/Monitor. Paclitaxel levels/efficacy may decrease when coadministered with CYP2C8 inducers

• pacritinib

  Contraindicated (1)isoniazid will increase the level or effect of pacritinib by affecting hepatic enzyme CYP2E1 metabolism. Contraindicated.Serious - Use Alternative (1)isoniazid will decrease the level or effect of pacritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• palbociclib

  Serious - Use Alternative (2)isoniazid will increase the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of palbociclib with strong CYP3A inhibitors. If unable to avoid, reduce palbociclib dose to 75 mg/day.
  
  rifampin will decrease the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A inducers decrease palbociclib plasma exposure by ~85%.

• paliperidone

  Monitor Closely (1)rifampin will decrease the level or effect of paliperidone by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Paliperidone dose may need to be increased when coadministered with strong inducers of both CYP3A4 and P-gp

• panobinostat

  Contraindicated (1)rifampin decreases levels of panobinostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inducers can reduce panobinostat levels by ~70% and lead to treatment failure.Monitor Closely (1)isoniazid increases levels of panobinostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce panobinostat starting dose to 10 mg if coadministered with strong CYP3A4 inhibitors.

• pantoprazole

  Monitor Closely (1)rifampin will decrease the level or effect of pantoprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• parecoxib

  Monitor Closely (2)rifampin will decrease the level or effect of parecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of parecoxib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of parecoxib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• paromomycin

  Monitor Closely (1)rifampin will decrease the level or effect of paromomycin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• paroxetine

  Monitor Closely (1)paroxetine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• pazopanib

  Monitor Closely (1)isoniazid will increase the level or effect of pazopanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of pazopanib with strong CYP3A4 inhibitors if possible; if must coadminister, decrease pazopanib dose to 400 mg/daySerious - Use Alternative (1)rifampin will decrease the level or effect of pazopanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• pemigatinib

  Serious - Use Alternative (2)rifampin will decrease the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pemigatinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pemigatinib dose.

• pentazocine

  Monitor Closely (1)isoniazid and pentazocine both increase serotonin levels. Use Caution/Monitor.

• pentobarbital

  Monitor Closely (1)rifampin decreases levels of pentobarbital by increasing metabolism. Use Caution/Monitor.

• perampanel

  Serious - Use Alternative (1)rifampin will decrease the level or effect of perampanel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Increased perampanel dose may be needed when coadministered

• perindopril

  Minor (1)rifampin decreases levels of perindopril by increasing metabolism. Minor/Significance Unknown.

• pexidartinib

  Serious - Use Alternative (4)rifampin and pexidartinib both increase inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.
  
  rifampin will increase the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pexidartinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pexidartinib dose.
  
  isoniazid and pexidartinib both increase inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.
  
  isoniazid will increase the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pexidartinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pexidartinib dose.

• phenelzine

  Serious - Use Alternative (1)phenelzine and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug.

• phenobarbital

  Monitor Closely (1)rifampin decreases levels of phenobarbital by increasing metabolism. Use Caution/Monitor.

• phenytoin

  Monitor Closely (1)rifampin will decrease the level or effect of phenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.Minor (1)isoniazid increases levels of phenytoin by decreasing metabolism. Minor/Significance Unknown.

• pimavanserin

  Monitor Closely (1)rifampin will decrease the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration if possible. Monitor for reduced pimavanserin efficacy. An increase in pimavanserin dosage may be needed.Serious - Use Alternative (1)isoniazid will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease dose to 17 mg/day if pimavanserin is coadministered with strong CYP3A4 inhibitors.

• pimozide

  Monitor Closely (2)isoniazid will increase the level or effect of pimozide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of pimozide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)isoniazid increases levels of pimozide by decreasing metabolism. Contraindicated. Risk of QT interval prolongation.

• pioglitazone

  Monitor Closely (1)rifampin will decrease the level or effect of pioglitazone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (2)isoniazid decreases effects of pioglitazone by unspecified interaction mechanism. Minor/Significance Unknown.
  
  isoniazid will increase the level or effect of pioglitazone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• pirfenidone

  Contraindicated (1)rifampin will decrease the level or effect of pirfenidone by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Use of strong CYP1A2 inducers should be discontinued before initiating pirfenidone and avoided during treatment

• pirmenol

  Minor (1)rifampin decreases levels of pirmenol by increasing metabolism. Minor/Significance Unknown.

• piroxicam

  Minor (1)rifampin will decrease the level or effect of piroxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• pitavastatin

  Monitor Closely (1)rifampin increases levels of pitavastatin by decreasing metabolism. Use Caution/Monitor. Do not exceed 2 mg/d pitavastatin.Serious - Use Alternative (1)rifampin increases toxicity of pitavastatin by Other (see comment). Avoid or Use Alternate Drug. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• pitolisant

  Monitor Closely (1)rifampin will decrease the level or effect of pitolisant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Pitolisant exposure is decreased by 50% if coadministered with strong CYP3A4 inducers. For patients stable on pitolisant 8.9 mg/day or 17.8 mg/day, double the pitolisant dose (ie, 17.8 mg or 35.6 mg, respectively) over 7 days. If the strong CYP3A4 inducer is discontinued, reduce pitolisant dosage by half.

• polatuzumab vedotin

  Monitor Closely (2)rifampin will decrease the level or effect of polatuzumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Polatuzumab undergoes catabolism to small peptides, amino acids, monomethyl auristatin E (MMAE), and unconjugated MMAE-related catabolites. MMAE is a CYP3A4 substrate. Coadministration of polatuzumab vedotin with a strong CYP3A4 inducer may decrease unconjugated MMAE AUC.
  
  isoniazid will increase the level or effect of polatuzumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Polatuzumab undergoes catabolism to small peptides, amino acids, monomethyl auristatin E (MMAE), and unconjugated MMAE-related catabolites. MMAE is a CYP3A4 substrate. Coadministration of polatuzumab vedotin with a strong CYP3A4 inhibitor may increase unconjugated MMAE AUC, which may increase polatuzumab vedotin toxicities.

• pomalidomide

  Serious - Use Alternative (4)rifampin decreases levels of pomalidomide by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid increases levels of pomalidomide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin decreases levels of pomalidomide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin decreases levels of pomalidomide by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• ponatinib

  Monitor Closely (1)ponatinib increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)rifampin decreases levels of ponatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid unless the coadministration outweighs the possible risk of ponatinib underexposure; monitor for signs of reduced efficacy.
  
  isoniazid increases levels of ponatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease ponatinib starting dose to 30 mg qDay if coadministration with strong CYP3A4 inhibitors cannot be avoided.

• ponesimod

  Serious - Use Alternative (1)rifampin will decrease the level or effect of ponesimod by Other (see comment). Avoid or Use Alternate Drug. Not recommended. Based on limited data, coadministration of strong CYP3A4 and UGT1A1 inducers (eg, rifampin, phenytoin, carbamazepine) may decrease systemic exposure of ponesimod. The clinical relevance is unclear.

• posaconazole

  Monitor Closely (2)rifampin will decrease the level or effect of posaconazole by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  rifampin decreases levels of posaconazole by increasing metabolism. Use Caution/Monitor.Minor (1)posaconazole decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Only applies to oral preparations of both agents.

• pralsetinib

  Serious - Use Alternative (2)rifampin will decrease the level or effect of pralsetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid, double current pralsetinib dose starting on Day 7 of coadministration with strong CYP3A inducer. After inducer has been discontinued for at least 14 days, resume previous pralsetinib dose.
  
  isoniazid will increase the level or effect of pralsetinib by affecting hepatic enzyme CYP2E1 metabolism. Avoid or Use Alternate Drug.

• pravastatin

  Monitor Closely (1)rifampin increases toxicity of pravastatin by Other (see comment). Use Caution/Monitor. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• praziquantel

  Contraindicated (1)rifampin decreases levels of praziquantel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP450 inducers significantly decrease praziquantel blood levels.

• prednisolone

  Monitor Closely (2)rifampin will decrease the level or effect of prednisolone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of prednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of prednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)prednisolone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• prednisone

  Monitor Closely (2)rifampin will decrease the level or effect of prednisone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of prednisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of prednisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)prednisone decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• pretomanid

  Serious - Use Alternative (3)rifampin, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.
  
  isoniazid, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid.
  
  rifampin will decrease the level or effect of pretomanid by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP3A4 substrate. Avoid coadministration of strong or moderate CYP3A4 inducers.

• primaquine

  Serious - Use Alternative (1)rifampin will decrease the level or effect of primaquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)primaquine, isoniazid. Mechanism: pharmacodynamic synergism. Minor/Significance Unknown. Risk of hemolysis in G6PD deficient pts.

• primidone

  Monitor Closely (1)rifampin decreases levels of primidone by increasing metabolism. Use Caution/Monitor.

• probenecid

  Monitor Closely (1)probenecid will increase the level or effect of rifampin by unspecified interaction mechanism. Use Caution/Monitor. Concomitant use with probenecid increase concentration of rifampin which may increase risk of toxicity; monitor for adverse reactions during coadministration

• progesterone intravaginal gel

  Serious - Use Alternative (1)rifampin will decrease the level or effect of progesterone intravaginal gel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use of nonhormonal contraceptives advised

• progesterone micronized

  Serious - Use Alternative (1)rifampin will decrease the level or effect of progesterone micronized by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use of nonhormonal contraceptives advised

• progesterone, natural

  Serious - Use Alternative (1)rifampin will decrease the level or effect of progesterone, natural by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use of nonhormonal contraceptives advised

• propafenone

  Monitor Closely (3)rifampin will decrease the level or effect of propafenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of propafenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin decreases levels of propafenone by increasing metabolism. Use Caution/Monitor.

• propofol

  Serious - Use Alternative (1)rifampin will decrease the level or effect of propofol by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug.

• propranolol

  Monitor Closely (1)rifampin decreases levels of propranolol by increasing metabolism. Use Caution/Monitor.

• protriptyline

  Monitor Closely (1)protriptyline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• pyrazinamide

  Serious - Use Alternative (1)rifampin, pyrazinamide. Either increases toxicity of the other by pharmacodynamic synergism. Avoid or Use Alternate Drug. Additive hepatotoxicity.Minor (1)isoniazid, pyrazinamide. Either increases toxicity of the other by pharmacodynamic synergism. Minor/Significance Unknown. Additive hepatotoxicity.

• pyridoxine

  Minor (1)isoniazid decreases levels of pyridoxine by unspecified interaction mechanism. Minor/Significance Unknown. If INH dose >10 mg/kg/day, supplement 50 100mg pyridoxine/day.

• pyridoxine (Antidote)

  Minor (1)isoniazid decreases levels of pyridoxine (Antidote) by unspecified interaction mechanism. Minor/Significance Unknown. If INH dose >10 mg/kg/day, supplement 50 100mg pyridoxine/day.

• quazepam

  Serious - Use Alternative (1)rifampin will decrease the level or effect of quazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• quetiapine

  Monitor Closely (1)isoniazid will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• quinapril

  Minor (1)rifampin decreases levels of quinapril by increasing metabolism. Minor/Significance Unknown.

• quinidine

  Monitor Closely (1)isoniazid will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• quinine

  Monitor Closely (2)rifampin will decrease the level or effect of quinine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of quinine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rabeprazole

  Monitor Closely (1)rifampin will decrease the level or effect of rabeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (2)rifampin will decrease the level or effect of rabeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
  
  isoniazid will increase the level or effect of rabeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• raltegravir

  Monitor Closely (1)rifampin decreases levels of raltegravir by increasing hepatic clearance. Use Caution/Monitor.

• ramelteon

  Monitor Closely (3)rifampin will decrease the level or effect of ramelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of ramelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of ramelteon by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Minor (2)rifampin will decrease the level or effect of ramelteon by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.
  
  isoniazid will increase the level or effect of ramelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ramipril

  Minor (1)rifampin decreases levels of ramipril by increasing metabolism. Minor/Significance Unknown.

• ranolazine

  Serious - Use Alternative (2)rifampin will decrease the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• rasagiline

  Monitor Closely (3)rifampin will decrease the level or effect of rasagiline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Rifampin is a relatively weak inducer of CYP1A2, caution is advised.
  
  rasagiline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.
  
  isoniazid will increase the level or effect of rasagiline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor. Isoniazid shows only negligible inhibition of CYP1A2, caution is advised. Recommended dose of rasagiline is 0.5mg daily in combination with CYP1A2 inhibitors.

• red yeast rice

  Serious - Use Alternative (1)isoniazid will increase the level or effect of red yeast rice by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. May increase creatine kinase levels and increase risk of myopathy or rhabdomyolysis; red yeast rice contains monocolin K (reportedly identical to lovastatin)

• regorafenib

  Contraindicated (2)rifampin, regorafenib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inducers decrease regorafenib levels and increase exposure of the active metabolite M-5.
  
  isoniazid, regorafenib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors increase regorafenib levels and decrease exposure of the active metabolites M-2 and M-5.

• repaglinide

  Monitor Closely (1)isoniazid will increase the level or effect of repaglinide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of repaglinide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)isoniazid decreases effects of repaglinide by unspecified interaction mechanism. Minor/Significance Unknown.

• revefenacin

  Serious - Use Alternative (1)rifampin increases levels of revefenacin by Other (see comment). Avoid or Use Alternate Drug. Comment: OATP1B1 and OATP1B3 transport inhibitors may increase systemic exposure of revefenacin's active metabolite. Coadministration not recommended.

• ribociclib

  Serious - Use Alternative (1)rifampin will decrease the level or effect of ribociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of ribociclib with strong CYP3A inducers should be avoided.

• rifabutin

  Serious - Use Alternative (1)rifampin will decrease the level or effect of rifabutin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• rifampin

  Serious - Use Alternative (1)rifampin increases toxicity of isoniazid by increasing metabolism. Avoid or Use Alternate Drug. Rifampin enhances the metabolism of isoniazid to hepatotoxic metabolites.

• rilpivirine

  Contraindicated (1)rifampin decreases levels of rilpivirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindicated. Rilpivirine should not be co-administered with strong CYP 3A4 inducers. Potential for loss of virologic response and possible resistance to rilpivirine or to the NNRTI class.Monitor Closely (1)isoniazid increases levels of rilpivirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• riluzole

  Monitor Closely (1)isoniazid will increase the level or effect of riluzole by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Minor (1)rifampin will decrease the level or effect of riluzole by affecting hepatic enzyme CYP1A2 metabolism. Minor/Significance Unknown.

• rimegepant

  Serious - Use Alternative (2)rifampin will decrease the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• riociguat

  Monitor Closely (1)rifampin will decrease the level or effect of riociguat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Data not available for dose adjustmentSerious - Use Alternative (1)isoniazid will increase the level or effect of riociguat by Other (see comment). Avoid or Use Alternate Drug. Coadministration of riociguat (an ABCG2 [BCRP] substrate) with strong ABCG2 inhibitors may require a decreased initial dose of 0.5 mg PO TID; monitor for signs of hypotension and reduce dose if needed

• ripretinib

  Monitor Closely (1)isoniazid will increase the level or effect of ripretinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with a strong CYP3A inhibitor will increase systemic exposure to ripretinib and its active metabolite (DP-5439), which may increase risk of adverse reactions.Serious - Use Alternative (1)rifampin will decrease the level or effect of ripretinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with a strong CYP3A inhibitor will decrease systemic exposure to ripretinib and its active metabolite (DP-5439), which may decrease risk of adverse reactions.

• risperidone

  Monitor Closely (1)rifampin will decrease the level or effect of risperidone by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• ritonavir

  Monitor Closely (2)isoniazid will increase the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of ritonavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• rivaroxaban

  Monitor Closely (1)rifampin decreases levels of rivaroxaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid concomitant use of rivaroxaban with drugs that are combined P-gp and strong CYP3A4 inducers. Consider increasing the rivaroxaban dose if these drugs must be coadministered.

• rizatriptan

  Monitor Closely (1)rizatriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.

• roflumilast

  Contraindicated (2)rifampin will decrease the level or effect of roflumilast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration not recommended; strong cytochrome P450 enzyme inducers decrease systemic exposure to roflumilast and may reduce the therapeutic effectiveness
  
  rifampin will decrease the level or effect of roflumilast by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated. Coadministration not recommended; strong cytochrome P450 enzyme inducers decrease systemic exposure to roflumilast and may reduce the therapeutic effectiveness

• rolapitant

  Serious - Use Alternative (1)rifampin will decrease the level or effect of rolapitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Long-term coadministration of strong CYP3A4 inducers with rolapitant may significantly decrease rolapitant efficacy.

• romidepsin

  Monitor Closely (2)isoniazid will increase the level or effect of romidepsin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of romidepsin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of romidepsin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong 3A4 inducers should be avoided if possible.

• ropinirole

  Monitor Closely (2)rifampin will decrease the level or effect of ropinirole by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of ropinirole by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.

• rosiglitazone

  Minor (1)isoniazid decreases effects of rosiglitazone by unspecified interaction mechanism. Minor/Significance Unknown.

• rosuvastatin

  Monitor Closely (1)rifampin increases toxicity of rosuvastatin by Other (see comment). Use Caution/Monitor. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• ruxolitinib

  Monitor Closely (1)rifampin will decrease the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)isoniazid will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce ruxolitinib starting dose to 10 mg BID with platelet count 100 X 10^9/L or more and concurrent use of strong CYP3A4 inhibitors; avoid with platelet counts <100 X 10^9/L

• ruxolitinib topical

  Monitor Closely (1)rifampin will decrease the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)isoniazid will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce ruxolitinib starting dose to 10 mg BID with platelet count 100 X 10^9/L or more and concurrent use of strong CYP3A4 inhibitors; avoid with platelet counts <100 X 10^9/L

• sacubitril/valsartan

  Monitor Closely (1)rifampin will increase the level or effect of sacubitril/valsartan by Other (see comment). Use Caution/Monitor. The results from an in vitro study with human liver tissue indicate that valsartan is a substrate of the hepatic uptake transporter OATP1B1; coadministration with OATP1B1 inhibitors may increase valsartan systemic exposure

• safinamide

  Monitor Closely (1)isoniazid, safinamide. Either increases toxicity of the other by serotonin levels. Modify Therapy/Monitor Closely. Monitor for hypertension and reaction to dietary tyramine in patients treated concomitantly with isoniazid and safinamide.

• SAMe

  Monitor Closely (1)isoniazid and SAMe both increase serotonin levels. Use Caution/Monitor.

• saquinavir

  Contraindicated (2)rifampin increases toxicity of saquinavir by unspecified interaction mechanism. Contraindicated. Adding rifampin to saquinavir/ritonaivr (ritonavir boosted saquinavir) may result in toxic hepatitis.
  
  rifampin will decrease the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindicated. May result in loss of antiviral efficacy and/or development of viral resistance.Monitor Closely (1)isoniazid will increase the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• sarecycline

  Monitor Closely (1)sarecycline will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor for toxicities of P-gp substrates that may require dosage reduction when coadministered with P-gp inhibitors.

• saxagliptin

  Monitor Closely (2)isoniazid will increase the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Limit saxagliptin dose to 2.5 mg/day when coadministered with strong CYP3A4 inhibitors
  
  rifampin will decrease the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• secobarbital

  Monitor Closely (1)rifampin decreases levels of secobarbital by increasing metabolism. Use Caution/Monitor.

• selegiline

  Monitor Closely (2)rifampin will decrease the level or effect of selegiline by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
  
  selegiline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• selegiline transdermal

  Monitor Closely (1)selegiline transdermal and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• selexipag

  Monitor Closely (1)rifampin will decrease the level or effect of selexipag by increasing metabolism. Modify Therapy/Monitor Closely. Coadministration of selexipag with rifampin, an inducer of CYP2C8, UGT1A3, and 2B7 enzymes, decreased exposure to selexipag's active metabolite by 50%. Increase selexipag dose up to twice of the typical dose if coadministered with rifampin.

• selpercatinib

  Serious - Use Alternative (1)rifampin will decrease the level or effect of selpercatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• selumetinib

  Serious - Use Alternative (2)isoniazid will increase the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors cannot be avoided, reduce selumetinib dosage (refer to selumetinib monograph for further information). After discontinuation of the strong or moderate CYP3A4 inhibitor for 3 elimination half-lives, resume selumetinib dose that was taken before initiating the inhibitor.
  
  rifampin will decrease the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sertraline

  Monitor Closely (1)sertraline and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• sevoflurane

  Monitor Closely (1)isoniazid will increase the level or effect of sevoflurane by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor.

• sildenafil

  Monitor Closely (2)rifampin will decrease the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potent CYP3A4 inducers are expected to cause substantial decreases in sildenafil plasma levels
  
  isoniazid will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• silodosin

  Monitor Closely (1)rifampin will decrease the level or effect of silodosin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)rifampin will decrease the level or effect of silodosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of silodosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• simvastatin

  Monitor Closely (1)rifampin will increase the level or effect of simvastatin by Other (see comment). Use Caution/Monitor. OATP1B1 inhibitors may increase risk of myopathySerious - Use Alternative (2)rifampin will decrease the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• siponimod

  Serious - Use Alternative (2)rifampin will decrease the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a drug that causes moderate CYP2C9 plus a moderate or strong CYP3A4 inducer is not recommended. Coadministration with moderate or strong CYP3A4 inducers alone is not recommended for patients with CYP2C9*1/*3 and*2/*3 genotype.
  
  isoniazid will increase the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a moderate or strong CYP3A4 inhibitor PLUS a moderate or strong CYP2C9 inhibitor is not recommended.

• sirolimus

  Monitor Closely (1)rifampin will decrease the level or effect of sirolimus by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)rifampin will decrease the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sitagliptin

  Minor (1)isoniazid decreases effects of sitagliptin by unspecified interaction mechanism. Minor/Significance Unknown.

• sodium bicarbonate

  Monitor Closely (2)sodium bicarbonate will decrease the level or effect of rifampin by Other (see comment). Use Caution/Monitor. Concomitant antacid administration may reduce absorption of rifampin; daily doses of rifampin should be given at least 1 hr before ingestion of antacids
  
  sodium bicarbonate decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• sodium citrate/citric acid

  Monitor Closely (1)sodium citrate/citric acid decreases levels of isoniazid by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Separate by 2 hours.

• sodium picosulfate/magnesium oxide/anhydrous citric acid

  Monitor Closely (2)rifampin decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.
  
  isoniazid decreases effects of sodium picosulfate/magnesium oxide/anhydrous citric acid by altering metabolism. Use Caution/Monitor. Coadministration with antibiotics decreases efficacy by altering colonic bacterial flora needed to convert sodium picosulfate to active drug.

• sodium sulfate/?magnesium sulfate/potassium chloride

  Monitor Closely (2)sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of isoniazid by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.
  
  sodium sulfate/?magnesium sulfate/potassium chloride increases toxicity of rifampin by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sodium sulfate/potassium sulfate/magnesium sulfate

  Monitor Closely (2)sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of rifampin by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.
  
  sodium sulfate/potassium sulfate/magnesium sulfate increases toxicity of isoniazid by Other (see comment). Use Caution/Monitor. Comment: Coadministration with medications that cause fluid and electrolyte abnormalities may increase the risk of adverse events of seizure, arrhythmias, and renal impairment.

• sofosbuvir

  Serious - Use Alternative (1)rifampin will decrease the level or effect of sofosbuvir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. P-gp inducers decrease sofosbuvir levels, and therefore decrease conversion to sofosbuvir's active metabolite (GS-331007) responsible for 90% of pharmacologic effect

• sofosbuvir/velpatasvir

  Serious - Use Alternative (3)rifampin will decrease the level or effect of sofosbuvir/velpatasvir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Sofosbuvir and velpatasvir are substrates of the drug transporter P-gp. Potent P-gp inducers may significantly decrease sofosbuvir and velpatasvir plasma concentrations, leading to potentially reduced therapeutic effect.
  
  rifampin will decrease the level or effect of sofosbuvir/velpatasvir by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug. Velpatasvir is a substrate of CYP2B6, CYP2C8, and CYP3A4. Drugs that are moderate-to-potent inducers of CYP2B6, CYP2C8, or CYP3A4 may significantly decrease velpatasvir plasma concentrations, leading to potentially reduced therapeutic effect.
  
  rifampin will decrease the level or effect of sofosbuvir/velpatasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Velpatasvir is a substrate of CYP2B6, CYP2C8, and CYP3A4. Drugs that are moderate-to-potent inducers of CYP2B6, CYP2C8, or CYP3A4 may significantly decrease velpatasvir plasma concentrations, leading to potentially reduced therapeutic effect.

• solifenacin

  Monitor Closely (1)isoniazid will increase the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sonidegib

  Serious - Use Alternative (2)isoniazid will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sonidegib with strong CYP3A4 inhibitors.
  
  rifampin will decrease the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sonidegib with strong or moderate CYP3A4 inducers.

• sorafenib

  Serious - Use Alternative (2)rifampin decreases levels of sorafenib by increasing metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of sorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sotorasib

  Serious - Use Alternative (2)rifampin will decrease the level or effect of sotorasib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  sotorasib will decrease the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If use is unavoidable, refer to the prescribing information of the P-gp substrate for dosage modifications.

• sparsentan

  Monitor Closely (1)sparsentan will decrease the level or effect of rifampin by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Sparsentan (a CYP2B6 inducer) decreases exposure of CYP2B6 substrates and reduces efficacy related to these substrates.Serious - Use Alternative (1)rifampin will decrease the level or effect of sparsentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• St John's Wort

  Monitor Closely (1)isoniazid and St John's Wort both increase serotonin levels. Modify Therapy/Monitor Closely.

• stiripentol

  Monitor Closely (2)stiripentol, rifampin. affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP2B6 inhibitor and inducer. Monitor CYP2B6 substrates coadministered with stiripentol for increased or decreased effects. CYP2B6 substrates may require dosage adjustment.
  
  stiripentol will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing the dose of P-glycoprotein (P-gp) substrates, if adverse reactions are experienced when administered concomitantly with stiripentol.Serious - Use Alternative (3)rifampin will decrease the level or effect of stiripentol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration of stiripentol with strong CYP3A4 inducers, increase stiripentol dose.
  
  rifampin will decrease the level or effect of stiripentol by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration of stiripentol with strong CYP1A2 inducers, increase stiripentol dose.
  
  rifampin will decrease the level or effect of stiripentol by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration of stiripentol with strong CYP1A2 inducers, increase stiripentol dose.

• streptomycin

  Monitor Closely (1)rifampin will decrease the level or effect of streptomycin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• sufentanil

  Monitor Closely (2)rifampin will decrease the level or effect of sufentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of sufentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• sufentanil SL

  Monitor Closely (2)rifampin decreases effects of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of CYP3A4 inducers may decrease sufentanil levels and efficacy, possibly precipitating withdrawal syndrome in patients who have developed physical dependence to sufentanil. Discontinuation of concomitantly used CYP3A4 inducers may increase sufentanil plasma concentration.
  
  isoniazid will increase the level or effect of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of sufentanil SL with any CYP3A4 inhibitor may increase sufentanil plasma concentration, and, thereby increase or prolonged adverse effects, including potentially fatal respiratory depression.

• sulbactam/durlobactam

  Serious - Use Alternative (1)rifampin will increase the level or effect of sulbactam/durlobactam by Other (see comment). Avoid or Use Alternate Drug. Sulbactam is predicted to have active secretion by OATP1 as a significant portion of total clearance; therefore, inhibition of OAT1 may increase sulbactam plasma concentrations

• sulfamethoxazole

  Minor (1)rifampin will decrease the level or effect of sulfamethoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• sumatriptan

  Monitor Closely (1)sumatriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.

• sumatriptan intranasal

  Monitor Closely (1)sumatriptan intranasal and isoniazid both increase serotonin levels. Use Caution/Monitor.

• sunitinib

  Monitor Closely (1)isoniazid will increase the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• suvorexant

  Monitor Closely (1)rifampin will decrease the level or effect of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inducers may decrease suvorexant efficacy; if increased suvorexant dose required, do not exceed 20 mg/daySerious - Use Alternative (1)isoniazid increases levels of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Suvorexant not recommended with use of strong CYP3A4 inhibitors.

• tacrolimus

  Monitor Closely (2)rifampin will decrease the level or effect of tacrolimus by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tadalafil

  Monitor Closely (2)rifampin will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid combination in pulmonary HTN patients. For patients with ED, monitor response to tadalafil carefully because of potential for decreased effectiveness.
  
  isoniazid will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. For ED limit tadalafil to max of 2.5 mg/day (for daily use) or 10 mg dose every 72 hr (for use as needed). Avoid concurrent use of tadalafil for pulmonary HTN in patients taking strong CYP3A4 inhibitors.

• tamoxifen

  Monitor Closely (3)rifampin will decrease the level or effect of tamoxifen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of tamoxifen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid, tamoxifen. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. CYP3A4 inhibition decreases metabolism of tamoxifen to N-desmethyl tamoxifen (active metabolite with similar biologic activity).

• tamsulosin

  Monitor Closely (1)isoniazid increases levels of tamsulosin by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)rifampin will decrease the level or effect of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tasimelteon

  Monitor Closely (2)rifampin will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
  
  isoniazid will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tazemetostat

  Serious - Use Alternative (2)rifampin will decrease the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of tazemetostat with moderate CYP3A4 inhibitors. If coadministration is unavoidable, reduce tazemetostat current dose (see drug monograph Dosage Modifications).

• temsirolimus

  Monitor Closely (1)isoniazid will increase the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• teniposide

  Monitor Closely (1)rifampin will decrease the level or effect of teniposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tepotinib

  Serious - Use Alternative (1)tepotinib will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If concomitant use unavoidable, reduce the P-gp substrate dosage if recommended in its approved product labeling.

• terbinafine

  Monitor Closely (3)rifampin will decrease the level or effect of terbinafine by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of terbinafine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of terbinafine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tetracycline

  Monitor Closely (1)rifampin will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tezacaftor

  Monitor Closely (1)isoniazid will increase the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust tezacaftor dosage regimen if coadministered with a strong CYP3A inhibitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• theophylline

  Monitor Closely (3)isoniazid will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of theophylline by affecting hepatic enzyme CYP1A2 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• thyroid desiccated

  Minor (1)rifampin decreases levels of thyroid desiccated by increasing metabolism. Minor/Significance Unknown.

• tiagabine

  Monitor Closely (1)rifampin will decrease the level or effect of tiagabine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• tibolone

  Minor (1)rifampin decreases levels of tibolone by increasing metabolism. Minor/Significance Unknown. Theoretical interaction.

• ticagrelor

  Monitor Closely (1)rifampin decreases levels of ticagrelor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid use of ticagrelor with potent CYP3A inducers.

• tinidazole

  Monitor Closely (1)rifampin will decrease the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tipranavir

  Contraindicated (1)rifampin will decrease the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindicated. May result in loss of antiviral efficacy and/or development of viral resistance. Monitor Closely (1)isoniazid will increase the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tisotumab vedotin

  Monitor Closely (1)isoniazid increases levels of tisotumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tisotumab vedotin?s active metabolite (MMAE) is a CYP3A4 substrate. Coadministration with strong CYP3A4 inhibitors may increase unconjugated MMAE systemic exposure and increase risk of adverse effects.

• tivozanib

  Serious - Use Alternative (1)rifampin will decrease the level or effect of tivozanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tizanidine

  Serious - Use Alternative (2)isoniazid will increase the level or effect of tizanidine by affecting hepatic enzyme CYP1A2 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of tizanidine by affecting hepatic enzyme CYP1A2 metabolism. Contraindicated.

• tobramycin

  Monitor Closely (1)rifampin will decrease the level or effect of tobramycin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• tofacitinib

  Monitor Closely (2)rifampin will decrease the level or effect of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Loss of, or decreased response to tofacitinib may occur when coadministered with potent CYP3A4 inducers
  
  isoniazid increases levels of tofacitinib by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. No specific dose adjustment recommended when tofacitinib coadministered with potent CYP2C19 inhibitors; decrease tofacitinib dose if coadministered with both moderate CYP3A4 and potent CYP2C19 inhibitors .Serious - Use Alternative (1)isoniazid increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce tofacitinib dose to 5 mg qDay when coadministered with potent CYP3A4 inhibitors.

• tolazamide

  Monitor Closely (1)rifampin decreases levels of tolazamide by increasing metabolism. Use Caution/Monitor.Minor (1)isoniazid decreases effects of tolazamide by unspecified interaction mechanism. Minor/Significance Unknown.

• tolbutamide

  Monitor Closely (1)rifampin decreases levels of tolbutamide by increasing metabolism. Use Caution/Monitor.Minor (2)isoniazid decreases effects of tolbutamide by unspecified interaction mechanism. Minor/Significance Unknown.
  
  rifampin will decrease the level or effect of tolbutamide by affecting hepatic enzyme CYP2C9/10 metabolism. Minor/Significance Unknown.

• tolterodine

  Monitor Closely (1)isoniazid will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tolvaptan

  Monitor Closely (1)rifampin will decrease the level or effect of tolvaptan by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)isoniazid will increase the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• toremifene

  Monitor Closely (2)rifampin decreases levels of toremifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inducers increase rate of toremifene metabolism, lowering the steady-state concentration in serum.
  
  isoniazid increases levels of toremifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Metabolism of toremifene may be inhibited by drugs known to inhibit CYP3A4 hepatic enzymes.

• trabectedin

  Serious - Use Alternative (2)isoniazid will increase the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If strong CYP3A inhibitor must be used, short-term (eg, less than 14 days), administer strong CYP3A inhibitor 1 week after trabectedin infusion, and discontinue the day prior to next trabectedin infusion
  
  rifampin will decrease the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tramadol

  Monitor Closely (2)rifampin will decrease the level or effect of tramadol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Decreased AUC of tramadol and the active metabolite (O-desmethyltramadol) when coadministered with strong CYP3A4 and CYP2B6 inducers
  
  isoniazid and tramadol both increase serotonin levels. Use Caution/Monitor.

• trandolapril

  Minor (1)rifampin decreases levels of trandolapril by increasing metabolism. Minor/Significance Unknown.

• tranylcypromine

  Serious - Use Alternative (1)tranylcypromine and isoniazid both increase serotonin levels. Avoid or Use Alternate Drug.

• trazodone

  Monitor Closely (2)isoniazid will increase the level or effect of trazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  trazodone and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)rifampin will decrease the level or effect of trazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• triamcinolone acetonide injectable suspension

  Monitor Closely (1)isoniazid will increase the level or effect of triamcinolone acetonide injectable suspension by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of triamcinolone acetonide injectable suspension by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)triamcinolone acetonide injectable suspension decreases effects of isoniazid by unknown mechanism. Minor/Significance Unknown.

• triazolam

  Monitor Closely (1)isoniazid will increase the level or effect of triazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of triazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• trimethoprim

  Monitor Closely (1)rifampin will decrease the level or effect of trimethoprim by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• trimipramine

  Monitor Closely (2)rifampin will decrease the level or effect of trimipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  trimipramine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• trofinetide

  Serious - Use Alternative (1)trofinetide will increase the level or effect of rifampin by Other (see comment). Avoid or Use Alternate Drug. Trofinetide (an OATP131 and OATP13B inhibitor) may increase plasma levels of OATP131 or OATP13B substrates. Avoid coadministration with sensitive substrates.

• tucatinib

  Monitor Closely (1)tucatinib will increase the level or effect of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Consider reducing the dosage of P-gp substrates, where minimal concentration changes may lead to serious or life-threatening toxicities.Serious - Use Alternative (2)rifampin will decrease the level or effect of tucatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  rifampin will decrease the level or effect of tucatinib by Other (see comment). Avoid or Use Alternate Drug. Coadministration of tucatinib (a CYP2C8 substrate) with a strong or moderate CYP2C8 inducer decreases tucatinib plasma concentrations.

• typhoid vaccine live

  Serious - Use Alternative (1)rifampin decreases levels of typhoid vaccine live by pharmacodynamic antagonism. Contraindicated.

• ubrogepant

  Monitor Closely (1)isoniazid will decrease the level or effect of ubrogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Dose adjustment is recommended with concomitant use of ubrogepant and moderate and weak CYP3A4 inducers. (see Dosage Modifications)Serious - Use Alternative (1)rifampin will decrease the level or effect of ubrogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ulipristal

  Serious - Use Alternative (1)rifampin will decrease the level or effect of ulipristal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• umeclidinium bromide/vilanterol inhaled

  Monitor Closely (1)isoniazid will increase the level or effect of umeclidinium bromide/vilanterol inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Vilanterol is a CYP3A4 substrate; coadministration with potent CYP3A4 inhibitors may increase systemic exposure

• upadacitinib

  Monitor Closely (1)isoniazid will increase the level or effect of upadacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution if upadacitinib is coadministered with strong CYP3A4 inhibitors.Serious - Use Alternative (1)rifampin will decrease the level or effect of upadacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid upadacitinib coadministration with strong CYP3A4 inducers.

• valbenazine

  Monitor Closely (1)isoniazid will increase the level or effect of valbenazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce valbenazine dose to 40 mg once daily when coadministered with a strong CYP3A4 inhibitor. Serious - Use Alternative (1)rifampin will decrease the level or effect of valbenazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Concomitant use not recommended.

• valproic acid

  Minor (1)isoniazid increases levels of valproic acid by decreasing metabolism. Minor/Significance Unknown.

• valsartan

  Monitor Closely (1)rifampin will increase the level or effect of valsartan by Other (see comment). Use Caution/Monitor. The results from an in vitro study with human liver tissue indicate that valsartan is a substrate of the hepatic uptake transporter OATP1B1; coadministration with OATP1B1 inhibitors may increase valsartan systemic exposure

• vandetanib

  Contraindicated (1)rifampin decreases levels of vandetanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid coadministration with potent CYP3A4 inducers; these drugs reduce exposure to vandetanib by up to 40%.

• vardenafil

  Monitor Closely (1)isoniazid will increase the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Vardenafil dose may need to be reduced if coadministered with moderate or strong CYP3A4 inhibitors Serious - Use Alternative (1)rifampin will decrease the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• velpatasvir

  Contraindicated (1)rifampin will decrease the level or effect of velpatasvir by affecting hepatic enzyme CYP2B6 metabolism. Contraindicated.Serious - Use Alternative (1)rifampin will decrease the level or effect of velpatasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• vemurafenib

  Monitor Closely (2)rifampin decreases levels of vemurafenib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  vemurafenib increases levels of rifampin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)rifampin decreases levels of vemurafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid increases levels of vemurafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• venetoclax

  Contraindicated (1)isoniazid will increase the level or effect of venetoclax by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Use of strong CYP3A4 inhibitors is contraindicated with venetoclax during the initial ramp-up dosing phase. If a strong CYP3A inhibitor must be used after the ramp-up phase, reduce the venetoclax dose by at least 75%.Serious - Use Alternative (1)rifampin will decrease the level or effect of venetoclax by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of venetoclax with strong or moderate CYP3A inducers. Consider alternative treatment with agents that have less CYP3A induction.

• venlafaxine

  Monitor Closely (1)venlafaxine and isoniazid both increase serotonin levels. Modify Therapy/Monitor Closely.

• verapamil

  Monitor Closely (1)isoniazid will increase the level or effect of verapamil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of verapamil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• vilanterol/fluticasone furoate inhaled

  Monitor Closely (1)isoniazid will increase the level or effect of vilanterol/fluticasone furoate inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Fluticasone furoate and vilanterol are both CYP3A4 substrates; coadministration with potent CYP3A4 inhibitors may increase systemic exposure

• vilazodone

  Monitor Closely (1)rifampin decreases levels of vilazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Consider increasing vilazodone dose up to 2-fold (not to exceed 80 mg/day) when coadministered with strong CYP3A4 inducers for >14 days.Serious - Use Alternative (2)isoniazid increases levels of vilazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors may increase vilazodone plasma levels by 50% - Reduce daily dose to 20 mg.
  
  isoniazid, vilazodone. Either increases toxicity of the other by serotonin levels. Avoid or Use Alternate Drug. Concomitant therapy should be discontinued immediately if signs or symptoms of serotonin syndrome emerge and supportive symptomatic treatment should be initiated. .

• vildagliptin

  Minor (1)isoniazid decreases effects of vildagliptin by unspecified interaction mechanism. Minor/Significance Unknown.

• vinblastine

  Monitor Closely (3)rifampin will decrease the level or effect of vinblastine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of vinblastine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of vinblastine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• vincristine

  Monitor Closely (3)rifampin will decrease the level or effect of vincristine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of vincristine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of vincristine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• vincristine liposomal

  Monitor Closely (3)rifampin will decrease the level or effect of vincristine liposomal by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of vincristine liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of vincristine liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• vinorelbine

  Monitor Closely (2)rifampin will decrease the level or effect of vinorelbine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  isoniazid will increase the level or effect of vinorelbine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• voclosporin

  Contraindicated (1)isoniazid will increase the level or effect of voclosporin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• vonoprazan

  Serious - Use Alternative (1)rifampin will decrease the level or effect of vonoprazan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• vorapaxar

  Serious - Use Alternative (2)rifampin decreases levels of vorapaxar by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  isoniazid increases levels of vorapaxar by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• voriconazole

  Contraindicated (1)rifampin decreases levels of voriconazole by increasing metabolism. Contraindicated.Monitor Closely (1)isoniazid will increase the level or effect of voriconazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifampin will decrease the level or effect of voriconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.Minor (1)voriconazole decreases levels of rifampin by inhibition of GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown. Only applies to oral preparations of both agents.

• vortioxetine

  Monitor Closely (2)rifampin decreases levels of vortioxetine by increasing metabolism. Modify Therapy/Monitor Closely. Consider increasing the vortioxetine dose when coadministered with strong CYP inducers for >14 days; not to exceed 3 times original vortioxetine dose.
  
  rifampin will decrease the level or effect of vortioxetine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider increasing vortioxetine dose when coadministered with a strong CYP inducer for >14 days. Do not exceed 3x the original dose. Reduce vortioxetine dose to original level within 14 days, when inducer is discontinued.

• voxelotor

  Serious - Use Alternative (1)rifampin will decrease the level or effect of voxelotor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor is primarily metabolized by CYP3A4. Avoid coadministration with moderate or strong CYP3A4 inducers. If unable to avoid coadministration, increase voxelotor dose (see Dosage Modifications).

• voxilaprevir

  Serious - Use Alternative (1)rifampin will decrease the level or effect of voxilaprevir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid use of voxilaprevir and rifampin. Rifampin is listed as contraindicated when coadministered with sofosbuvir/velpatasvir/voxilaprevir in the prescribing information.

• warfarin

  Monitor Closely (2)isoniazid will increase the level or effect of warfarin by Other (see comment). Use Caution/Monitor. Warfarin's less potent R-enantiomer is metabolized in part by CYP3A4 (and also CYP1A2 and CYP2C19). Monitor INR more frequently if coadministered with inhibitors of these isoenzymes and adjust warfarin dose if needed.
  
  rifampin will decrease the level or effect of warfarin by affecting hepatic enzyme CYP2C9/10 metabolism. Modify Therapy/Monitor Closely.

• zaleplon

  Monitor Closely (1)rifampin will decrease the level or effect of zaleplon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of zaleplon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zanubrutinib

  Monitor Closely (1)isoniazid will increase the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce zanubrutinib (a CYP3A4 substrate) to 80 mg PO BID to when coadministered with a moderate CYP3A4 inhibitor. Interrupt dose as recommended for adverse reactions. After discontinuing the CYP3A4 inhibitor, resume previous dose of zanubrutinib. Serious - Use Alternative (1)rifampin will decrease the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• zavegepant intranasal

  Serious - Use Alternative (1)rifampin will increase the level or effect of zavegepant intranasal by Other (see comment). Avoid or Use Alternate Drug. OATP1B3 inhibitors may result in a significant increase in systemic exposure of zavegepant (an OATP1B3 substrate).

• zidovudine

  Monitor Closely (1)rifampin decreases levels of zidovudine by increasing metabolism. Use Caution/Monitor.

• ziprasidone

  Monitor Closely (1)rifampin will decrease the level or effect of ziprasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of ziprasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zolmitriptan

  Monitor Closely (1)zolmitriptan and isoniazid both increase serotonin levels. Use Caution/Monitor.

• zolpidem

  Monitor Closely (1)rifampin will decrease the level or effect of zolpidem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)isoniazid will increase the level or effect of zolpidem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zonisamide

  Monitor Closely (2)isoniazid will increase the level or effect of zonisamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  rifampin will decrease the level or effect of zonisamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.