efavirenz (Rx)

HIV Infection

Indicated in combination with other antiretroviral agents for HIV-1 infection

600 mg PO qDay; used in combination with protease inhibitor and/or NRTIs

Dosage Modifications

Coadministration with voriconazole: Increase voriconazole maintenance dose to 400 mg q12hr and decrease efavirenz dose to 300 mg qDay (using capsule formulation)

Coadministration with rifampin: If weight >50 kg, increase efavirenz to 800 mg qDay

Renal impairment: No dosage adjustment needed

Hepatic impairment

• Mild (Child-Pugh Class A): Dose adjustment not necessary; use caution
• Moderate-to-severe (Child Pugh Class B or C): Not recommended

HIV Infection

NOTE: The NIH pediatric HIV treatment guideline (March 2016) differs from the prescribing information and recommends that efavirenz generally should NOT be used in children aged <3 yr

Indicated in combination with other antiretroviral agents for HIV-1 infection in pediatric patients >3 months old and weighing ≥3.5 kg

<3 months: Safety and efficacy not established

≥3 months (prescribing information)

• 3.5 kg to <5 kg: 100 mg PO qDay
• 5 to <7.5 kg: 150 mg PO qDay
• 7.5 to <15 kg: 200 mg PO qDay
• 15 to <20 kg: 250 mg PO qDay
• 20 to <25 kg: 300 mg PO qDay
• 25 to <32.5 kg: 350 mg PO qDay
• 32.5 to <40 kg: 400 mg PO qDay
• ≥40 kg: 600 mg PO qDay

NIH pediatric HIV treatment guidelines (March 2016)

• Investigational dosing for 3 months to <3 years based on CYP 2B6 genotype

• Extensive metabolizers (ie, CYP 2B6 516 GG and GT genotype)

  • 3 to <5 kg: 200 mg PO qDay
  • 5 to <7 kg: 300 mg PO qDay
  • 7 to <14 kg: 400 mg PO qDay
  • 14 to <17 kg: 500 mg PO qDay
  • ≥17 kg: 600 mg PO qDay

• Slow metabolizers (ie, CYP 2B6 516 TT genotype)

  • 3 to <7 kg: 50 mg PO qDay
  • 7 to <14 kg: 100 mg PO qDay
  • ≥14kg: 150 mg PO qDay

• ≥3 years

  • 10 to <15 kg: 200 mg PO qDay
  • 15 to <20 kg: 250 mg PO qDay
  • 20 to <25 kg: 300 mg PO qDay
  • 25 to <32.5 kg: 350 mg PO qDay
  • 32.5 to <40 kg: 400 mg PO qDay
  • ≥40 kg: 600 mg PO qDay

Dosage Modifications

Coadministration with voriconazole: If weight >40 kg and age >12 yr, increase voriconazole maintenance dose to 400 mg q12hr and decrease efavirenz dose to 300 mg qDay (using capsule formulation)

Coadministration with rifampin: If weight >40 kg, increase efavirenz to 800 mg qDay

Renal impairment: No dosage adjustment needed

Hepatic impairment

• Mild (Child-Pugh Class A): Dose adjustment not necessary; use caution
• Moderate-to-severe (Child Pugh Class B or C): Not recommended

Contraindicated (27)

• carbamazepine

  carbamazepine, efavirenz. Either decreases levels of the other by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of carbamazepine with NNRTIs may result in a loss of virologic response and possible resistance to the NNRTI. A decrease in AUC is observed for both carbamazepine (27%) and efavirenz (36%) when coadministered.

• cariprazine

  efavirenz 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.

• cobimetinib

  efavirenz 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.

• dienogest/estradiol valerate

  efavirenz will decrease the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Women should not choose estradiol valerate/dienogest as their contraceptive while using strong CYP3A4 inducers due to potential decrease in contraceptive efficacy. Estradiol valerate/dienogest should not be used for at least 28 days after discontinuation of the inducer due to possibility of decreased contraceptive efficacy.

• doravirine

  efavirenz 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.

• dronedarone

  efavirenz and dronedarone both increase QTc interval. Contraindicated.

• elbasvir/grazoprevir

  efavirenz 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.

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  efavirenz, elvitegravir/cobicistat/emtricitabine/tenofovir DF. Other (see comment). Contraindicated. Comment: Elvitegravir/cobicistat/emtricitabine/tenofovir is a complete regimen for HIV and should not be administered with other antiretrovirals.

• ergonovine

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

• etravirine

  efavirenz decreases levels of etravirine by increasing metabolism. Contraindicated. Mfr.'s PI recommends not combining etravirine with other NNRTIs.

• fostemsavir

  efavirenz 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.

• isavuconazonium sulfate

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

• lefamulin

  lefamulin will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lefamulin is contraindicated with CYP3A substrates know to prolong the QT interval.

• lomitapide

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

• lonafarnib

  efavirenz 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.

• lorlatinib

  efavirenz 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.

• lumacaftor/ivacaftor

  efavirenz 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.

• mavacamten

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

• nevirapine

  efavirenz and nevirapine both increase risk of immune reconstitution syndrome. Contraindicated. Coadministration not recommended as this combination has been associated with an increase in adverse reactions and no improvement in efficacy

• ombitasvir/paritaprevir/ritonavir

  efavirenz will decrease the level or effect of ombitasvir/paritaprevir/ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)

  ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC), efavirenz. unspecified interaction mechanism. Contraindicated. Coadministration of avirenz-based regimens with Viekira Pak was poorly tolerated and resulted in liver enzyme elevations.
  
  efavirenz will decrease the level or effect of ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• panobinostat

  efavirenz 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.

• posaconazole

  efavirenz and posaconazole both increase QTc interval. Contraindicated.

• praziquantel

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

• ranolazine

  efavirenz and ranolazine both increase QTc interval. Contraindicated.

• rilpivirine

  efavirenz decreases levels of rilpivirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindicated. Rilpivirine should not be used in combination with NNRTIs.

• voriconazole

  voriconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindication applies to efavirenz doses of 400 mg/day or higher. This dose of efavirenz induces CYP3A4 resulting in decreased voriconazole levels. When voriconazole is coadministered with efavirenz, voriconazole oral maintenance dose should be increased to 400 mg q12hr and efavirenz should be decreased to 300 mg q24hr.
  
  efavirenz decreases effects of voriconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindication applies to efavirenz doses of 400 mg/day or higher. This dose of efavirenz induces CYP3A4 resulting in decreased voriconazole levels. When voriconazole is coadministered with efavirenz, voriconazole oral maintenance dose should be increased to 400 mg q12hr and efavirenz should be decreased to 300 mg q24hr.

Serious - Use Alternative (217)

• abametapir

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

  efavirenz 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

  efavirenz will increase the level or effect of abrocitinib by decreasing metabolism. Avoid or Use Alternate Drug. Abrocitinib is a CYP2C9 and CYP2C19 substrate. Drugs that are moderate-to-strong inhibitors of both CYP2C9 and CYP2C19 increase systemic exposure of abrocitinib and its active metabolites, which may increase adverse effects.

• alfuzosin

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

• alpelisib

  efavirenz 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.

• amiodarone

  efavirenz will decrease the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and amiodarone both increase QTc interval. Avoid or Use Alternate Drug.

• amisulpride

  efavirenz and amisulpride both increase QTc interval. Avoid or Use Alternate Drug. ECG monitoring is recommended if coadministered.

• anagrelide

  efavirenz and anagrelide both increase QTc interval. Avoid or Use Alternate Drug.

• apalutamide

  apalutamide will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.
  
  efavirenz will decrease the level or effect of apalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. No initial dose adjustment

• apremilast

  efavirenz 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

• artemether

  efavirenz and artemether both increase QTc interval. Avoid or Use Alternate Drug.

• artemether/lumefantrine

  efavirenz will decrease the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong CYP3A4 inducers can result in decreased serum concentrations and loss of antimalarial efficacy
  
  efavirenz and artemether/lumefantrine both increase QTc interval. Avoid or Use Alternate Drug.

• asenapine

  efavirenz and asenapine both increase QTc interval. Avoid or Use Alternate Drug.

• asenapine transdermal

  asenapine transdermal and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• atazanavir

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

• atovaquone

  efavirenz decreases levels of atovaquone by unspecified interaction mechanism. Avoid or Use Alternate Drug.

• axitinib

  efavirenz 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.

• azithromycin

  efavirenz and azithromycin both increase QTc interval. Avoid or Use Alternate Drug.

• bedaquiline

  efavirenz 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
  
  efavirenz and bedaquiline both increase QTc interval. Avoid or Use Alternate Drug.

• betibeglogene autotemcel

  efavirenz, betibeglogene autotemcel. Other (see comment). Avoid or Use Alternate Drug. Comment: Do not take antiretroviral medications for at least 1 month before mobilization or expected duration for elimination of the medications, and until all cycles of apheresis are completed. Antiretroviral medications may interfere with manufacturing of apheresed cells.

• bosutinib

  efavirenz 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

  efavirenz 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.

• bromocriptine

  efavirenz increases levels of bromocriptine by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.

• buprenorphine

  efavirenz and buprenorphine both increase QTc interval. Avoid or Use Alternate Drug.

• buprenorphine buccal

  buprenorphine buccal and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• buprenorphine subdermal implant

  buprenorphine subdermal implant and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• buprenorphine transdermal

  efavirenz will decrease the level or effect of buprenorphine transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  buprenorphine transdermal and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• buprenorphine, long-acting injection

  buprenorphine, long-acting injection and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• cabergoline

  efavirenz increases levels of cabergoline by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.

• cabotegravir

  efavirenz, cabotegravir. Other (see comment). Avoid or Use Alternate Drug. Comment: Cabotegravir plus rilpivirine is a complete regimen. Coadministration with other antiretroviral medications for treating HIV-1 infection is not recommended.

• cabozantinib

  efavirenz 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.

• capmatinib

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

• carvedilol

  efavirenz will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.

• ceritinib

  efavirenz decreases levels of ceritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and ceritinib both increase QTc interval. Avoid or Use Alternate Drug.
  
  ceritinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• chloroquine

  efavirenz and chloroquine both increase QTc interval. Avoid or Use Alternate Drug.

• chlorpromazine

  efavirenz and chlorpromazine both increase QTc interval. Avoid or Use Alternate Drug.

• citalopram

  efavirenz will decrease the level or effect of citalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and citalopram both increase QTc interval. Avoid or Use Alternate Drug.

• clarithromycin

  efavirenz and clarithromycin both increase QTc interval. Avoid or Use Alternate Drug.

• clopidogrel

  efavirenz decreases effects of clopidogrel by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Clopidogrel efficacy may be reduced by drugs that inhibit CYP2C19. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. Clopidogrel is metabolized to this active metabolite in part by CYP2C19. .

• cobicistat

  efavirenz will decrease the level or effect of cobicistat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with efavirenz may result in loss of therapeutic effect and development of resistance to cobicistat.

• copanlisib

  efavirenz 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.

• crizotinib

  efavirenz and crizotinib both increase QTc interval. Avoid or Use Alternate Drug.

• dabrafenib

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

• daridorexant

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

• darolutamide

  efavirenz 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

  efavirenz will decrease the level or effect of darunavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with efavirenz may result in loss of therapeutic effect and development of resistance to darunavir

• deflazacort

  efavirenz 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.

• dihydroergotamine

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

• dihydroergotamine intranasal

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

• disopyramide

  efavirenz and disopyramide both increase QTc interval. Avoid or Use Alternate Drug.

• dofetilide

  efavirenz and dofetilide both increase QTc interval. Avoid or Use Alternate Drug.

• dolutegravir

  efavirenz 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

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

• droperidol

  efavirenz and droperidol both increase QTc interval. Avoid or Use Alternate Drug.

• duvelisib

  efavirenz 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.

• elacestrant

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

• eletriptan

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

• elivaldogene autotemcel

  elivaldogene autotemcel, efavirenz. Either decreases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Patients should not take antiretroviral medications for at least 1 month before initiating medications for stem cell mobilization, for the duration of the medications? elimination, and until all cycles of apheresis are completed.

• eltrombopag

  efavirenz will increase the level or effect of eltrombopag by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.

• elvitegravir

  efavirenz 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

  efavirenz will decrease the level or effect of elvitegravir/cobicistat/emtricitabine/tenofovir DF by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• encorafenib

  efavirenz will decrease the level or effect of encorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and encorafenib both increase QTc interval. Avoid or Use Alternate Drug.
  
  encorafenib and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• entrectinib

  efavirenz and entrectinib both increase QTc interval. Avoid or Use Alternate Drug.
  
  efavirenz will decrease the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• enzalutamide

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

• erdafitinib

  efavirenz will decrease the level or effect of erdafitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz will increase the level or effect of erdafitinib by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. If coadministration of a strong CYP2C9 inhibitors is unavoidable, closely monitor adverse reactions and modify dose of erdafitinib accordingly. If strong CYP2C9 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities.

• ergoloid mesylates

  efavirenz increases levels of ergoloid mesylates by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.

• ergotamine

  efavirenz will decrease the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  efavirenz increases levels of ergotamine by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.

• eribulin

  efavirenz and eribulin both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin base

  efavirenz will decrease the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  efavirenz and erythromycin base both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin ethylsuccinate

  efavirenz will decrease the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  efavirenz and erythromycin ethylsuccinate both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin lactobionate

  efavirenz will decrease the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  efavirenz and erythromycin lactobionate both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin stearate

  efavirenz will decrease the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  efavirenz and erythromycin stearate both increase QTc interval. Avoid or Use Alternate Drug.

• ethinylestradiol

  efavirenz 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.

• ethotoin

  efavirenz will increase the level or effect of ethotoin by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.

• etravirine

  efavirenz will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.

• everolimus

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

• fedratinib

  efavirenz 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.

• fexinidazole

  efavirenz 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.
  
  fexinidazole will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug. Coadministration may decrease plasma concentrations of CYP2B6 substrates owing to fexinidazole inducing CYP2B6.
  
  fexinidazole and efavirenz both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval.
  
  fexinidazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.

• finerenone

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

• fingolimod

  fingolimod and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• flecainide

  efavirenz and flecainide both increase QTc interval. Avoid or Use Alternate Drug.

• foscarnet

  efavirenz and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

• fosphenytoin

  efavirenz will increase the level or effect of fosphenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.

• fostamatinib

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

• ganaxolone

  efavirenz 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.

• gemtuzumab

  efavirenz and gemtuzumab both increase QTc interval. Avoid or Use Alternate Drug.

• glasdegib

  efavirenz 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.
  
  efavirenz and glasdegib both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, monitor for increased risk of QTc interval prolongation.

• glecaprevir/pibrentasvir

  efavirenz will decrease the level or effect of glecaprevir/pibrentasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of efavirenz (a strong CYP3A4 inducer) with glecaprevir/pibrentasvir may significantly decrease glecaprevir/pibrentasvir plasma concentrations and AUC. Potential for loss of therapeutic effect.

• hydroxychloroquine sulfate

  efavirenz and hydroxychloroquine sulfate both increase QTc interval. Avoid or Use Alternate Drug.

• ibrutinib

  efavirenz 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.

• ibutilide

  efavirenz and ibutilide both increase QTc interval. Avoid or Use Alternate Drug.

• idelalisib

  efavirenz 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
  
  idelalisib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates

• iloperidone

  efavirenz and iloperidone both increase QTc interval. Avoid or Use Alternate Drug.

• indinavir

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

• infigratinib

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

• inotuzumab

  efavirenz and inotuzumab both increase QTc interval. Avoid or Use Alternate Drug.

• irinotecan

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

• irinotecan liposomal

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

• isoflurane

  efavirenz and isoflurane both increase QTc interval. Avoid or Use Alternate Drug.

• istradefylline

  efavirenz 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

  itraconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Not recommended 2 weeks before and during itraconazole.
  
  efavirenz will decrease the level or effect of itraconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Not recommended 2 weeks before and during itraconazole.
  
  efavirenz and itraconazole both increase QTc interval. Avoid or Use Alternate Drug.

• ivabradine

  efavirenz 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

  efavirenz, ivacaftor. Other (see comment). Avoid or Use Alternate Drug. Comment: Efavirenz decreases levels of ivacaftor by CYP enzyme induction; whereas, ivacaftor increases levels of efavirenz by inhibiting CYP3A4 .

• ivosidenib

  efavirenz 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.
  
  efavirenz and ivosidenib both decrease QTc interval. Avoid or Use Alternate Drug.

• ixazomib

  efavirenz 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%.

• larotrectinib

  efavirenz 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

• lefamulin

  efavirenz and lefamulin both increase QTc interval. Avoid or Use Alternate Drug.

• lemborexant

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

• lenacapavir

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

• lenvatinib

  efavirenz and lenvatinib both increase QTc interval. Avoid or Use Alternate Drug.

• letermovir

  efavirenz 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.

• lofexidine

  efavirenz and lofexidine both increase QTc interval. Avoid or Use Alternate Drug.

• lopinavir

  lopinavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and lopinavir both increase QTc interval. Avoid or Use Alternate Drug.

• lorlatinib

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

• lovastatin

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

• lumateperone

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

• lumefantrine

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

• lurbinectedin

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

• macimorelin

  efavirenz 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.
  
  efavirenz and macimorelin both increase QTc interval. Avoid or Use Alternate Drug.

• macitentan

  efavirenz 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

• methadone

  efavirenz and methadone both increase QTc interval. Avoid or Use Alternate Drug.

• methylergonovine

  efavirenz increases levels of methylergonovine by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.

• metoclopramide intranasal

  efavirenz, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.

• midostaurin

  efavirenz 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.
  
  efavirenz and midostaurin both increase QTc interval. Avoid or Use Alternate Drug.

• mifepristone

  mifepristone will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz will decrease the level or effect of mifepristone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and mifepristone both increase QTc interval. Avoid or Use Alternate Drug.

• mobocertinib

  efavirenz will decrease the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and mobocertinib both increase QTc interval. Avoid or Use Alternate Drug.

• moxifloxacin

  efavirenz and moxifloxacin both increase QTc interval. Avoid or Use Alternate Drug.

• naloxegol

  efavirenz will decrease the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use of naloxegol with strong CYP3A4 inducers is not recommended

• nateglinide

  efavirenz will increase the level or effect of nateglinide by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.

• nefazodone

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

• neratinib

  efavirenz 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.

• netupitant/palonosetron

  efavirenz 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

  nevirapine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration not recommended as this combination has been associated with an increase in adverse reactions and no improvement in efficacy
  
  efavirenz will decrease the level or effect of nevirapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• nilotinib

  efavirenz and nilotinib both increase QTc interval. Avoid or Use Alternate Drug.

• nisoldipine

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

• norethindrone

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

• norgestrel

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

• olaparib

  efavirenz will decrease the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with moderate CYP3A inducers cannot be avoided, be aware of a potential for decreased efficacy of olaparib

• olopatadine intranasal

  efavirenz and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• olutasidenib

  efavirenz 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

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

• ondansetron

  efavirenz and ondansetron both increase QTc interval. Avoid or Use Alternate Drug.

• osimertinib

  efavirenz 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.
  
  efavirenz and osimertinib both increase QTc interval. Avoid or Use Alternate Drug.

• oxaliplatin

  efavirenz and oxaliplatin both increase QTc interval. Avoid or Use Alternate Drug.

• ozanimod

  efavirenz and ozanimod both increase QTc interval. Avoid or Use Alternate Drug.

• panobinostat

  efavirenz and panobinostat both increase QTc interval. Avoid or Use Alternate Drug.

• parecoxib

  efavirenz will increase the level or effect of parecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.

• pazopanib

  efavirenz and pazopanib both increase QTc interval. Avoid or Use Alternate Drug.

• pemigatinib

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

• pentamidine

  efavirenz and pentamidine both increase QTc interval. Avoid or Use Alternate Drug.

• perampanel

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

• pexidartinib

  efavirenz will decrease the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and pexidartinib both increase Other (see comment). Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.

• pimavanserin

  efavirenz and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.

• pimozide

  efavirenz and pimozide both increase QTc interval. Contraindicated.

• pitolisant

  efavirenz and pitolisant both increase QTc interval. Avoid or Use Alternate Drug.

• pomalidomide

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

• ponesimod

  efavirenz and ponesimod both increase QTc interval. Avoid or Use Alternate Drug.

• pralsetinib

  efavirenz 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.

• pretomanid

  efavirenz 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.
  
  efavirenz, 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.

• procainamide

  efavirenz and procainamide both increase QTc interval. Avoid or Use Alternate Drug.

• propafenone

  efavirenz and propafenone both increase QTc interval. Avoid or Use Alternate Drug.

• quetiapine

  efavirenz and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• quinidine

  efavirenz and quinidine both increase QTc interval. Avoid or Use Alternate Drug.

• quinine

  efavirenz and quinine both increase QTc interval. Avoid or Use Alternate Drug.

• ranolazine

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

• regorafenib

  efavirenz will decrease the level or effect of regorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inducers decrease regorafenib levels and increase exposure of the active metabolite M-5

• ribociclib

  ribociclib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and ribociclib both increase QTc interval. Avoid or Use Alternate Drug.

• rifabutin

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

• rilpivirine

  efavirenz and rilpivirine both increase QTc interval. Avoid or Use Alternate Drug.

• rimegepant

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

• ripretinib

  efavirenz 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

  efavirenz and risperidone both increase QTc interval. Avoid or Use Alternate Drug.

• rolapitant

  efavirenz 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.

• ropeginterferon alfa 2b

  ropeginterferon alfa 2b and efavirenz both increase Other (see comment). Avoid or Use Alternate Drug. Narcotics, hypnotics or sedatives can produce additive neuropsychiatric side effects. Avoid use and monitor patients receiving the combination for effects of excessive CNS toxicity.

• saquinavir

  saquinavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and saquinavir both increase QTc interval. Avoid or Use Alternate Drug.

• selpercatinib

  efavirenz will decrease the level or effect of selpercatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and selpercatinib both increase QTc interval. Avoid or Use Alternate Drug.

• selumetinib

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

• sevoflurane

  efavirenz and sevoflurane both increase QTc interval. Avoid or Use Alternate Drug.

• silodosin

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

• siponimod

  efavirenz will increase the level or effect of siponimod by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with drugs that cause moderate CYP2C9 AND a moderate or strong CYP3A4 inhibition is not recommended. Caution if siponimod coadministered with moderate CYP2C9 inhibitors alone.
  
  efavirenz 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.
  
  efavirenz and siponimod both increase QTc interval. Avoid or Use Alternate Drug.

• sirolimus

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

• sofosbuvir/velpatasvir

  efavirenz 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.

• sonidegib

  efavirenz 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

  efavirenz will decrease the level or effect of sorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and sorafenib both increase QTc interval. Avoid or Use Alternate Drug.

• sotalol

  efavirenz and sotalol both increase QTc interval. Avoid or Use Alternate Drug.

• sotorasib

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

• St John's Wort

  St John's Wort will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• stiripentol

  efavirenz 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.

• sunitinib

  efavirenz and sunitinib both increase QTc interval. Avoid or Use Alternate Drug.

• suvorexant

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

• tacrolimus

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

• tazemetostat

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

• tepotinib

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

• tetrabenazine

  efavirenz and tetrabenazine both increase QTc interval. Avoid or Use Alternate Drug.

• tezacaftor

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

• thiothixene

  efavirenz and thiothixene both increase QTc interval. Contraindicated.

• tivozanib

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

• tolvaptan

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

• toremifene

  efavirenz and toremifene both increase QTc interval. Avoid or Use Alternate Drug.

• trabectedin

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

• trazodone

  efavirenz and trazodone both increase QTc interval. Avoid or Use Alternate Drug.

• triazolam

  efavirenz increases levels of triazolam by decreasing metabolism. Contraindicated.

• tucatinib

  efavirenz will decrease the level or effect of tucatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz will increase 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 inhibitors increases tucatinib plasma concentrations and risk of toxicities.
  
  tucatinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.

• ubrogepant

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

• ulipristal

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

• upadacitinib

  efavirenz 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.

• vandetanib

  efavirenz decreases levels of vandetanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with potent CYP3A4 inducers; these drugs reduce exposure to vandetanib by up to 40%.
  
  efavirenz and vandetanib both increase QTc interval. Avoid or Use Alternate Drug.

• velpatasvir

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

• vemurafenib

  efavirenz will decrease the level or effect of vemurafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and vemurafenib both increase QTc interval. Avoid or Use Alternate Drug.

• venetoclax

  efavirenz 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.

• voclosporin

  efavirenz will decrease the level or effect of voclosporin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and voclosporin both increase QTc interval. Avoid or Use Alternate Drug.

• vonoprazan

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

• voriconazole

  efavirenz and voriconazole both increase QTc interval. Avoid or Use Alternate Drug.

• voxelotor

  efavirenz 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).
  
  voxelotor will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.

• voxilaprevir

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

• zanubrutinib

  efavirenz will decrease the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of zanubrutinib (a CYP3A4 substrate) with moderate CYP3A4 inhibitors. If unavoidable, increase zanubrutinib dose to 320 mg PO BID. After discontinuing the CYP3A4 inhibitor, resume previous dose of zanubrutinib.

• ziprasidone

  efavirenz and ziprasidone both increase QTc interval. Avoid or Use Alternate Drug.

Monitor Closely (334)

• abacavir

  abacavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• abiraterone

  efavirenz 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.

• acalabrutinib

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

• acrivastine

  acrivastine and efavirenz both increase sedation. Use Caution/Monitor.

• albuterol

  efavirenz and albuterol both increase QTc interval. Use Caution/Monitor.

• alfentanil

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

• alfuzosin

  efavirenz and alfuzosin both increase QTc interval. Use Caution/Monitor.

• almotriptan

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

• alosetron

  efavirenz will increase the level or effect of alosetron by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• alprazolam

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

• amisulpride

  amisulpride and efavirenz both increase sedation. Use Caution/Monitor.

• amitriptyline

  efavirenz will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and amitriptyline both increase QTc interval. Use Caution/Monitor.

• amlodipine

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

• apixaban

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

• apomorphine

  efavirenz and apomorphine both increase QTc interval. Use Caution/Monitor.

• aprepitant

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

• arformoterol

  efavirenz and arformoterol both increase QTc interval. Use Caution/Monitor.

• aripiprazole

  efavirenz will decrease the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and aripiprazole both increase QTc interval. Use Caution/Monitor.

• arsenic trioxide

  efavirenz and arsenic trioxide both increase QTc interval. Use Caution/Monitor.

• asenapine

  asenapine and efavirenz both increase sedation. Use Caution/Monitor.

• asenapine transdermal

  asenapine transdermal and efavirenz both increase sedation. Use Caution/Monitor.

• atazanavir

  atazanavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• atogepant

  efavirenz 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.

• atomoxetine

  efavirenz and atomoxetine both increase QTc interval. Use Caution/Monitor.

• atorvastatin

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

• avanafil

  efavirenz will decrease the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; increased levels may result in increased associated adverse events; the maximum recommended dose of STENDRA is 50 mg, not to exceed once every 24 hours for patients taking concomitant moderate CYP3A4 inhibitors

• avapritinib

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

• bazedoxifene/conjugated estrogens

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

• belumosudil

  efavirenz will increase 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

  belzutifan will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If unable to avoid coadministration of belzutifan with sensitive CYP3A4 substrates, consider increasing the sensitive CYP3A4 substrate dose in accordance with its prescribing information.

• benzhydrocodone/acetaminophen

  efavirenz 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.

• bortezomib

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

• bosentan

  efavirenz will increase the level or effect of bosentan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• brentuximab vedotin

  efavirenz will decrease the level or effect of brentuximab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• brexanolone

  brexanolone, efavirenz. Either increases toxicity of the other by sedation. Use Caution/Monitor.

• brexpiprazole

  efavirenz 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.

• buprenorphine

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

• buprenorphine buccal

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

• buprenorphine subdermal implant

  efavirenz 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.

• buprenorphine, long-acting injection

  efavirenz 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

  efavirenz will decrease the level or effect of bupropion by increasing metabolism. Use Caution/Monitor. Coadministration with hepatic inducers reduced bupropion AUC and Cmax; hydroxybupropion (active metabolite) Cmax was increased

• buspirone

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

• cabazitaxel

  efavirenz will increase the level or effect of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution should be exercised with concomitant use of moderate CYP3A4 inhibitors.

• calcifediol

  efavirenz, calcifediol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Drugs that stimulate microsomal hydroxylation reduce the half-life of calcifediol.

• calcitriol

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

• cannabidiol

  efavirenz 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 moderate CYP2C19 inhibitor.
  
  efavirenz 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.
  
  cannabidiol, efavirenz. 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.

• carbamazepine

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

• celecoxib

  efavirenz will increase the level or effect of celecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• cenobamate

  cenobamate will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP2B6 substrate, as needed, when coadministered with cenobamate.
  
  cenobamate will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.
  
  cenobamate, efavirenz. Either increases levels of the other by sedation. Use Caution/Monitor.

• chlordiazepoxide

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

• chloroquine

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

• chlorpheniramine

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

• cilostazol

  efavirenz will decrease the level or effect of cilostazol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz increases toxicity of cilostazol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider decreasing cilostazol dose; moderate CYP2C19 inhibitors may increase serum levels of 3,4-dehydrocilostazol (active metabolite).

• cinacalcet

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

• ciprofloxacin

  efavirenz and ciprofloxacin both increase QTc interval. Use Caution/Monitor.

• cisapride

  efavirenz and cisapride both increase QTc interval. Use Caution/Monitor.

• clarithromycin

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

• clobazam

  efavirenz 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).
  
  efavirenz, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).

• clomipramine

  efavirenz and clomipramine both increase QTc interval. Use Caution/Monitor.

• clonazepam

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

• clopidogrel

  efavirenz decreases effects of clopidogrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Clopidogrel efficacy may be reduced by drugs that inhibit CYP3A4. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. Clopidogrel is metabolized to this active metabolite in part by CYP3A4. .

• clorazepate

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

• clozapine

  efavirenz will decrease the level or effect of clozapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and clozapine both increase QTc interval. Use Caution/Monitor.

• cobicistat

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

• conivaptan

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

• conjugated estrogens

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

• conjugated estrogens, vaginal

  efavirenz will decrease the level or effect of conjugated estrogens, vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cortisone

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

• crizotinib

  efavirenz increases levels of crizotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution should be exercised with concomitant use of moderate CYP3A inhibitors. .

• crofelemer

  crofelemer increases levels of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.

• cyclophosphamide

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

• cyclosporine

  efavirenz will decrease the level or effect of cyclosporine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Closely monitor cyclosporine concentrations when starting, stopping, or adjusting dose of concurrent efavirez, especially within first 2 weeks.

• dabrafenib

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

• dantrolene

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

• dapsone

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

• daridorexant

  efavirenz and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• darifenacin

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

• darunavir

  darunavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• dasatinib

  efavirenz will decrease the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and dasatinib both increase QTc interval. Use Caution/Monitor.

• deferasirox

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

• degarelix

  efavirenz and degarelix both increase QTc interval. Use Caution/Monitor.

• desipramine

  efavirenz and desipramine both increase QTc interval. Use Caution/Monitor.

• deutetrabenazine

  efavirenz and deutetrabenazine both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).

• dexamethasone

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

• diazepam

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

• diazepam intranasal

  efavirenz 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.
  
  efavirenz 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.

• diclofenac

  efavirenz will increase the level or effect of diclofenac by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• didanosine

  didanosine, efavirenz. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Concomitant administration increases risk of liver toxicity.

• difelikefalin

  difelikefalin and efavirenz both increase sedation. Use Caution/Monitor.

• diltiazem

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

• docetaxel

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

• dolasetron

  efavirenz and dolasetron both increase QTc interval. Use Caution/Monitor.

• donepezil

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

• doxepin

  efavirenz and doxepin both increase QTc interval. Use Caution/Monitor.

• doxorubicin

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

• doxorubicin liposomal

  efavirenz will decrease the level or effect of doxorubicin liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dronabinol

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

• dronedarone

  dronedarone will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. May decrease dronedarone levels.

• elagolix

  efavirenz will decrease the level or effect of elagolix by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  elagolix will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.

• eliglustat

  efavirenz will decrease the level or effect of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A inducers significantly decreases eliglustat exposure; coadministration not recommended
  
  efavirenz and eliglustat both increase QTc interval. Use Caution/Monitor.

• emtricitabine

  efavirenz and emtricitabine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• encorafenib

  encorafenib, efavirenz. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.

• enfuvirtide

  efavirenz and enfuvirtide both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• erlotinib

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

• erythromycin base

  erythromycin base will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• erythromycin ethylsuccinate

  erythromycin ethylsuccinate will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• erythromycin lactobionate

  erythromycin lactobionate will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• erythromycin stearate

  erythromycin stearate will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• escitalopram

  efavirenz will increase the level or effect of escitalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of escitalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and escitalopram both increase QTc interval. Use Caution/Monitor.

• esketamine intranasal

  esketamine intranasal, efavirenz. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.

• eslicarbazepine acetate

  eslicarbazepine acetate will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• esomeprazole

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

• estradiol

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

• estradiol vaginal

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

• estrogens conjugated synthetic

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

• estrogens esterified

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

• estropipate

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

• eszopiclone

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

• ethosuximide

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

• etonogestrel

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

• etoposide

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

• etravirine

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

• exemestane

  efavirenz 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

  fedratinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.

• felbamate

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

• felodipine

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

• fentanyl

  efavirenz 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.

• fentanyl intranasal

  efavirenz 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

  efavirenz 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

  efavirenz 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.

• fesoterodine

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

• flibanserin

  efavirenz 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.

• fluconazole

  efavirenz and fluconazole both increase QTc interval. Use Caution/Monitor.

• fludrocortisone

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

• fluoxetine

  efavirenz and fluoxetine both increase QTc interval. Use Caution/Monitor.

• fluphenazine

  efavirenz and fluphenazine both increase QTc interval. Use Caution/Monitor.

• flurazepam

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

• flurbiprofen

  efavirenz will increase the level or effect of flurbiprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• fluvastatin

  efavirenz will increase the level or effect of fluvastatin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• fluvoxamine

  fluvoxamine will increase the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
  
  efavirenz and fluvoxamine both increase QTc interval. Use Caution/Monitor.

• formoterol

  efavirenz and formoterol both increase QTc interval. Use Caution/Monitor.

• fosamprenavir

  efavirenz will decrease the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  fosamprenavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• fosaprepitant

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

• fostemsavir

  efavirenz and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.

• ganaxolone

  efavirenz and ganaxolone both increase sedation. Use Caution/Monitor.

• gefitinib

  efavirenz 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.

• gemifloxacin

  efavirenz and gemifloxacin both increase QTc interval. Use Caution/Monitor.

• gilteritinib

  efavirenz and gilteritinib both increase QTc interval. Use Caution/Monitor.

• goserelin

  efavirenz and goserelin both increase QTc interval. Use Caution/Monitor.

• granisetron

  efavirenz and granisetron both increase QTc interval. Use Caution/Monitor.

• guanfacine

  efavirenz 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

  efavirenz will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and haloperidol both increase QTc interval. Use Caution/Monitor.

• histrelin

  efavirenz and histrelin both increase QTc interval. Use Caution/Monitor.

• hydrocodone

  efavirenz 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

• hydrocortisone

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

• hydroxyprogesterone caproate

  efavirenz will decrease the level or effect of hydroxyprogesterone caproate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• hydroxyzine

  efavirenz and hydroxyzine both increase QTc interval. Use Caution/Monitor.

• ibuprofen

  efavirenz will increase the level or effect of ibuprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• ibuprofen IV

  efavirenz will increase the level or effect of ibuprofen IV by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• ifosfamide

  efavirenz 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.
  
  efavirenz 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.

• iloperidone

  efavirenz will decrease the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  iloperidone increases levels of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.

• imipramine

  efavirenz will increase the level or effect of imipramine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  efavirenz and imipramine both increase QTc interval. Use Caution/Monitor.

• indacaterol, inhaled

  efavirenz and indacaterol, inhaled both increase QTc interval. Use Caution/Monitor.

• indinavir

  indinavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• isoniazid

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

• isosorbide dinitrate

  efavirenz will decrease the level or effect of isosorbide dinitrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isosorbide mononitrate

  efavirenz will decrease the level or effect of isosorbide mononitrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isradipine

  efavirenz will decrease the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and isradipine both increase QTc interval. Use Caution/Monitor.

• istradefylline

  istradefylline will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.

• ivacaftor

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

• ivosidenib

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

• ixabepilone

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

• ketamine

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

• ketoconazole

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

• lamivudine

  efavirenz and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• lansoprazole

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

• lapatinib

  efavirenz will decrease the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and lapatinib both increase QTc interval. Use Caution/Monitor.

• lasmiditan

  lasmiditan, efavirenz. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.

• lemborexant

  lemborexant will decrease the level or effect of efavirenz 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.

• letermovir

  letermovir increases levels of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• leuprolide

  efavirenz and leuprolide both increase QTc interval. Use Caution/Monitor.

• levalbuterol

  efavirenz and levalbuterol both increase QTc interval. Use Caution/Monitor.

• levamlodipine

  efavirenz will decrease the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No information is available on the quantitative effects of CYP3A4 inducers on amlodipine. Closely monitor blood pressure when amlodipine is coadministered with CYP3A4 inducers.

• levofloxacin

  efavirenz and levofloxacin both increase QTc interval. Use Caution/Monitor.

• levoketoconazole

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

• levonorgestrel intrauterine

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

• levonorgestrel oral

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

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  efavirenz 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.

• linagliptin

  efavirenz 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.
  
  efavirenz will decrease the level or effect of linagliptin by Other (see comment). Use Caution/Monitor. Reports of hyperglycemia due to insulin resistance with protease inhibitors.

• lithium

  efavirenz and lithium both increase QTc interval. Use Caution/Monitor.

• loperamide

  efavirenz and loperamide both increase QTc interval. Use Caution/Monitor.

• lopinavir

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

• loratadine

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

• losartan

  efavirenz will increase the level or effect of losartan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.
  
  efavirenz will decrease the level or effect of losartan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lumacaftor/ivacaftor

  lumacaftor/ivacaftor, efavirenz. affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2B6 substrates. .

• lurasidone

  efavirenz decreases levels of lurasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. It may be necessary to increase the lurasidone dose after chronic treatment (ie, 7 days or more) with moderate CYP3A inducers.
  
  lurasidone, efavirenz. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.

• maprotiline

  efavirenz and maprotiline both increase QTc interval. Use Caution/Monitor.

• maraviroc

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

• marijuana

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

• medroxyprogesterone

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

• mefloquine

  efavirenz will decrease the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and mefloquine both increase QTc interval. Use Caution/Monitor.

• meloxicam

  efavirenz will increase the level or effect of meloxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• meperidine

  efavirenz will decrease the level or effect of meperidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased toxic metabolite formation.

• mestranol

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

• metaxalone

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

• methadone

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

• methylprednisolone

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

• midazolam

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

• midazolam intranasal

  midazolam intranasal, efavirenz. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.

• mifepristone

  efavirenz, mifepristone. Other (see comment). Use Caution/Monitor. Comment: Efavirenz shown in vitro to induce CYP3A4 and CYP2B6, but in vitro has been shown to inhibit CYP3A4 and therefore may affect mifepristone levels/effect; mifepristone inhibits CYP2B6, therefore increasing exposure of efavirenz.

• mirtazapine

  efavirenz will decrease the level or effect of mirtazapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and mirtazapine both increase QTc interval. Use Caution/Monitor.

• mitotane

  mitotane decreases levels of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.

• modafinil

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

• nafcillin

  nafcillin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inducers may increase metabolism of CYP3A4 substrates

• naldemedine

  efavirenz will decrease the level or effect of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Simulation using physiologically-based pharmacokinetic modeling suggests that concomitant use of moderated CYP3A4 inducers decrease exposure to naldemedine. The clinical consequence of this decreased exposure is unknown.

• nefazodone

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

• nelfinavir

  efavirenz will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• nicardipine

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

• nifedipine

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

• nilotinib

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

• nirmatrelvir

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

• nirmatrelvir/ritonavir

  nirmatrelvir/ritonavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nortriptyline

  efavirenz and nortriptyline both increase QTc interval. Use Caution/Monitor.

• octreotide

  efavirenz and octreotide both increase QTc interval. Use Caution/Monitor.

• ofloxacin

  efavirenz and ofloxacin both increase QTc interval. Use Caution/Monitor.

• olanzapine

  efavirenz and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• oliceridine

  efavirenz 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.

• olodaterol inhaled

  efavirenz and olodaterol inhaled both increase QTc interval. Use Caution/Monitor.

• omeprazole

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

• ondansetron

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

• orlistat

  orlistat will decrease the level or effect of efavirenz by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Loss of virological control reported in HIV-infected patients taking orlistat concomitantly. Exact mechanism is unclear, but may include a drug-drug interaction that inhibits systemic absorption of the antiretroviral drug. Monitor HIV RNA levels frequently and if increased HIV viral load confirmed, discontinue orlistat.

• osilodrostat

  efavirenz will decrease the level or effect of osilodrostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor cortisol concentration and patient?s signs and symptoms during coadministration or discontinuation with strong CYP3A4 inducers. Adjust dose of osilodrostat if necessary.
  
  osilodrostat and efavirenz both increase QTc interval. Use Caution/Monitor.

• ospemifene

  efavirenz decreases levels of ospemifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• oxaliplatin

  oxaliplatin will increase the level or effect of efavirenz by Other (see comment). Use Caution/Monitor. Monitor for ECG changes if therapy is initiated in patients with drugs known to prolong QT interval.

• oxcarbazepine

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

• oxycodone

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

• palbociclib

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

• paricalcitol

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

• pasireotide

  efavirenz and pasireotide both increase QTc interval. Use Caution/Monitor.

• pazopanib

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

• perphenazine

  efavirenz and perphenazine both increase QTc interval. Use Caution/Monitor.

• phenytoin

  efavirenz will increase the level or effect of phenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  phenytoin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. When given together, periodic monitoring for reduced efavirenz efficacy and phenytoin plasma concentrations are recommended .
  
  phenytoin will increase the level or effect of efavirenz by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• pimavanserin

  efavirenz 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

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

• piroxicam

  efavirenz will increase the level or effect of piroxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• pitolisant

  efavirenz 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

  efavirenz 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.

• prednisolone

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

• prednisone

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

• primaquine

  efavirenz will decrease the level or effect of primaquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and primaquine both increase QTc interval. Use Caution/Monitor.

• prochlorperazine

  efavirenz and prochlorperazine both decrease QTc interval. Use Caution/Monitor.

• progesterone intravaginal gel

  efavirenz will decrease the level or effect of progesterone intravaginal gel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• progesterone micronized

  efavirenz will decrease the level or effect of progesterone micronized by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• progesterone, natural

  efavirenz will decrease the level or effect of progesterone, natural by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• proguanil

  efavirenz decreases levels of proguanil by unspecified interaction mechanism. Use Caution/Monitor. May decrease serum concentrations of the active metabolite of proguanil.

• promethazine

  efavirenz and promethazine both decrease QTc interval. Use Caution/Monitor.

• protriptyline

  efavirenz and protriptyline both increase QTc interval. Use Caution/Monitor.

• quazepam

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

• quetiapine

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

• quinidine

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

• ramelteon

  efavirenz will increase the level or effect of ramelteon by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• repaglinide

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

• ribociclib

  efavirenz will decrease the level or effect of ribociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of ribociclib with strong CYP3A inducers should be avoided.

• rifabutin

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

• rifampin

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

• riociguat

  efavirenz 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

• risperidone

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

• ritonavir

  efavirenz will decrease the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  ritonavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• rivaroxaban

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

• roflumilast

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

• romidepsin

  efavirenz will decrease the level or effect of romidepsin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with strong 3A4 inducers should be avoided if possible.
  
  efavirenz and romidepsin both increase QTc interval. Use Caution/Monitor.

• rucaparib

  rucaparib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.

• ruxolitinib

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

• ruxolitinib topical

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

• salmeterol

  efavirenz and salmeterol both increase QTc interval. Use Caution/Monitor.

• saquinavir

  efavirenz will decrease the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  saquinavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• selexipag

  efavirenz will increase the level or effect of selexipag by decreasing metabolism. Modify Therapy/Monitor Closely. Reduce selexipag dose to once daily if coadministered with moderate CYP2C8 inhibitors.

• sertraline

  efavirenz will decrease the level or effect of sertraline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and sertraline both increase QTc interval. Use Caution/Monitor.

• sildenafil

  efavirenz 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

• simvastatin

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

• solifenacin

  efavirenz will decrease the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and solifenacin both increase QTc interval. Use Caution/Monitor.

• sorafenib

  efavirenz decreases levels of sorafenib by increasing metabolism. Use Caution/Monitor.

• sparsentan

  sparsentan will decrease the level or effect of efavirenz 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.

• stavudine

  efavirenz and stavudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• stiripentol

  stiripentol, efavirenz. 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, efavirenz. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.
  
  stiripentol, efavirenz. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.

• sufentanil SL

  efavirenz 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.

• sulfamethoxazole

  efavirenz will increase the level or effect of sulfamethoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• sunitinib

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

• tacrolimus

  efavirenz and tacrolimus both increase QTc interval. Use Caution/Monitor.

• tadalafil

  efavirenz 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.

• tamoxifen

  efavirenz, tamoxifen. affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. CYP2C9/10 inhibition decreases tamoxifen metabolism to active metabolites.
  
  efavirenz, tamoxifen. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibition decreases metabolism of tamoxifen to N-desmethyl tamoxifen (active metabolite with similar biologic activity).

• tamsulosin

  efavirenz increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.

• tasimelteon

  efavirenz 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

• tazemetostat

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

• tecovirimat

  tecovirimat will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

• telavancin

  efavirenz and telavancin both increase QTc interval. Use Caution/Monitor.

• telotristat ethyl

  telotristat ethyl will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Consider increasing dosage of interacting drug, if necessary

• temsirolimus

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

• teniposide

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

• tenofovir DF

  efavirenz and tenofovir DF both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• terbinafine

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

• tetracycline

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

• theophylline

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

• tiagabine

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

• ticagrelor

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

• ticlopidine

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

• tinidazole

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

• tipranavir

  efavirenz will decrease the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tipranavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
  
  tipranavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tofacitinib

  efavirenz increases levels 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.

• tolbutamide

  efavirenz will increase the level or effect of tolbutamide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• tolterodine

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

• toremifene

  efavirenz 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.

• tramadol

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

• trazodone

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

• triamcinolone acetonide injectable suspension

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

• triazolam

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

• triclabendazole

  efavirenz and triclabendazole both increase QTc interval. Use Caution/Monitor.

• trifluoperazine

  efavirenz and trifluoperazine both decrease QTc interval. Use Caution/Monitor.

• trimipramine

  efavirenz will decrease the level or effect of trimipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of trimipramine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  efavirenz and trimipramine both increase QTc interval. Use Caution/Monitor.

• triptorelin

  efavirenz and triptorelin both increase QTc interval. Use Caution/Monitor.

• ublituximab

  ublituximab decreases effects of efavirenz by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely.

• umeclidinium bromide/vilanterol inhaled

  efavirenz will decrease the level or effect of umeclidinium bromide/vilanterol inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and umeclidinium bromide/vilanterol inhaled both decrease QTc interval. Use Caution/Monitor.

• valbenazine

  valbenazine and efavirenz both increase QTc interval. Use Caution/Monitor.

• vardenafil

  efavirenz will decrease the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and vardenafil both increase QTc interval. Use Caution/Monitor.

• venlafaxine

  efavirenz will decrease the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and venlafaxine both decrease QTc interval. Use Caution/Monitor.

• verapamil

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

• vilanterol/fluticasone furoate inhaled

  efavirenz will decrease the level or effect of vilanterol/fluticasone furoate inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid or Use Alternate Drug.
  
  efavirenz and vilanterol/fluticasone furoate inhaled both increase QTc interval. Use Caution/Monitor.

• vilazodone

  efavirenz 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.

• vorapaxar

  efavirenz decreases levels of vorapaxar by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• vorinostat

  efavirenz and vorinostat both increase QTc interval. Use Caution/Monitor.

• vortioxetine

  efavirenz 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.

• warfarin

  efavirenz will decrease 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 inducers of these isoenzymes and adjust warfarin dose if needed.

• zidovudine

  efavirenz and zidovudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• zonisamide

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

Minor (98)

• acetazolamide

  acetazolamide will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• alosetron

  efavirenz will decrease the level or effect of alosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ambrisentan

  efavirenz will decrease the level or effect of ambrisentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• amobarbital

  amobarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• anastrozole

  anastrozole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• aprepitant

  aprepitant will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• armodafinil

  armodafinil will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  efavirenz will decrease the level or effect of armodafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• artemether/lumefantrine

  artemether/lumefantrine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• atazanavir

  atazanavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  efavirenz decreases levels of atazanavir by unspecified interaction mechanism. Minor/Significance Unknown. May be coadministered; see atazanavir monograph for dosing info.

• bosentan

  bosentan will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  efavirenz will decrease the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• butabarbital

  butabarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• butalbital

  butalbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• caspofungin

  efavirenz decreases levels of caspofungin by increasing metabolism. Minor/Significance Unknown.

• cevimeline

  efavirenz will decrease the level or effect of cevimeline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• cimetidine

  efavirenz will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• clarithromycin

  efavirenz will decrease the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• clomipramine

  efavirenz will decrease the level or effect of clomipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• cocaine topical

  efavirenz will increase the level or effect of cocaine topical by affecting hepatic enzyme CYP2B6 metabolism. Minor/Significance Unknown.

• colchicine

  efavirenz will decrease the level or effect of colchicine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• conivaptan

  conivaptan will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• cortisone

  cortisone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• cyclophosphamide

  cyclophosphamide will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• cyclosporine

  cyclosporine will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• darifenacin

  darifenacin will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• darunavir

  darunavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• dasatinib

  dasatinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• dexamethasone

  dexamethasone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• DHEA, herbal

  DHEA, herbal will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• diazepam

  efavirenz will increase the level or effect of diazepam by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• disopyramide

  efavirenz will decrease the level or effect of disopyramide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• dutasteride

  efavirenz will decrease the level or effect of dutasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• eplerenone

  efavirenz will decrease the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• esomeprazole

  efavirenz will increase the level or effect of esomeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• etravirine

  etravirine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• eucalyptus

  efavirenz will decrease the level or effect of eucalyptus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• finasteride

  efavirenz will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• fluconazole

  fluconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• fludrocortisone

  fludrocortisone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• fosamprenavir

  fosamprenavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• fosaprepitant

  fosaprepitant will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• fosphenytoin

  fosphenytoin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• galantamine

  efavirenz will decrease the level or effect of galantamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• grapefruit

  grapefruit will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• griseofulvin

  griseofulvin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• hydrocortisone

  hydrocortisone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• imatinib

  efavirenz will decrease the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• imipramine

  efavirenz will decrease the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• indinavir

  indinavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ketoconazole

  efavirenz will decrease the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• lansoprazole

  efavirenz will increase the level or effect of lansoprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• lapatinib

  lapatinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• larotrectinib

  larotrectinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• levoketoconazole

  efavirenz will decrease the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• losartan

  efavirenz decreases effects of losartan by decreasing metabolism. Minor/Significance Unknown. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.

• lumefantrine

  lumefantrine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• marijuana

  marijuana will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• methylprednisolone

  methylprednisolone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• metronidazole

  metronidazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• miconazole vaginal

  miconazole vaginal will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• montelukast

  efavirenz will decrease the level or effect of montelukast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nelfinavir

  nelfinavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nifedipine

  nifedipine will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nilotinib

  nilotinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nimodipine

  efavirenz will decrease the level or effect of nimodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nitrendipine

  efavirenz will decrease the level or effect of nitrendipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• oxybutynin

  efavirenz will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• paclitaxel

  efavirenz will decrease the level or effect of paclitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• paclitaxel protein bound

  efavirenz will decrease the level or effect of paclitaxel protein bound by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• pantoprazole

  efavirenz will increase the level or effect of pantoprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• parecoxib

  efavirenz will decrease the level or effect of parecoxib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• pentobarbital

  pentobarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• phenobarbital

  phenobarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• pioglitazone

  efavirenz will decrease the level or effect of pioglitazone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ponatinib

  efavirenz decreases levels of ponatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. Avoid unless the coadministration outweighs the possible risk of ponatinib underexposure; monitor for signs of reduced efficacy.

• posaconazole

  posaconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• prednisone

  prednisone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• primidone

  primidone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• propafenone

  efavirenz will decrease the level or effect of propafenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• quinine

  efavirenz will decrease the level or effect of quinine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• quinupristin/dalfopristin

  quinupristin/dalfopristin will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• rabeprazole

  efavirenz will increase the level or effect of rabeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
  
  efavirenz will decrease the level or effect of rabeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ramelteon

  efavirenz will decrease the level or effect of ramelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• rifapentine

  rifapentine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ritonavir

  ritonavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• rufinamide

  rufinamide will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• saxagliptin

  efavirenz will decrease the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• secobarbital

  secobarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• sufentanil

  efavirenz will decrease the level or effect of sufentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• topiramate

  topiramate will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• verapamil

  verapamil will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• vinblastine

  efavirenz will decrease the level or effect of vinblastine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• vincristine

  efavirenz will decrease the level or effect of vincristine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• vincristine liposomal

  efavirenz will decrease the level or effect of vincristine liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• vinorelbine

  efavirenz will decrease the level or effect of vinorelbine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zafirlukast

  zafirlukast will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zaleplon

  efavirenz will decrease the level or effect of zaleplon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ziprasidone

  efavirenz will decrease the level or effect of ziprasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zolpidem

  efavirenz will decrease the level or effect of zolpidem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• abacavir

  Monitor Closely (1)abacavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• abametapir

  Serious - Use Alternative (2)abametapir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  abametapir will increase the level or effect of efavirenz 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

  Serious - Use Alternative (1)efavirenz 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)efavirenz 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

  Serious - Use Alternative (1)efavirenz will increase the level or effect of abrocitinib by decreasing metabolism. Avoid or Use Alternate Drug. Abrocitinib is a CYP2C9 and CYP2C19 substrate. Drugs that are moderate-to-strong inhibitors of both CYP2C9 and CYP2C19 increase systemic exposure of abrocitinib and its active metabolites, which may increase adverse effects.

• acalabrutinib

  Monitor Closely (1)efavirenz will decrease the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• acetazolamide

  Minor (1)acetazolamide will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• acrivastine

  Monitor Closely (1)acrivastine and efavirenz both increase sedation. Use Caution/Monitor.

• albuterol

  Monitor Closely (1)efavirenz and albuterol both increase QTc interval. Use Caution/Monitor.

• alfentanil

  Monitor Closely (1)efavirenz will decrease the level or effect of alfentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• alfuzosin

  Monitor Closely (1)efavirenz and alfuzosin both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz will decrease the level or effect of alfuzosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• almotriptan

  Monitor Closely (1)efavirenz will decrease the level or effect of almotriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• alosetron

  Monitor Closely (1)efavirenz will increase the level or effect of alosetron by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.Minor (1)efavirenz will decrease the level or effect of alosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• alpelisib

  Serious - Use Alternative (1)efavirenz 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)efavirenz will decrease the level or effect of alprazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ambrisentan

  Minor (1)efavirenz will decrease the level or effect of ambrisentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• amiodarone

  Serious - Use Alternative (2)efavirenz and amiodarone both increase QTc interval. Avoid or Use Alternate Drug.
  
  efavirenz will decrease the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• amisulpride

  Monitor Closely (1)amisulpride and efavirenz both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and amisulpride both increase QTc interval. Avoid or Use Alternate Drug. ECG monitoring is recommended if coadministered.

• amitriptyline

  Monitor Closely (3)efavirenz will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  efavirenz and amitriptyline both increase QTc interval. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• amlodipine

  Monitor Closely (1)efavirenz will decrease the level or effect of amlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• amobarbital

  Minor (1)amobarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• anagrelide

  Serious - Use Alternative (1)efavirenz and anagrelide both increase QTc interval. Avoid or Use Alternate Drug.

• anastrozole

  Minor (1)anastrozole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• apalutamide

  Serious - Use Alternative (2)apalutamide will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.
  
  efavirenz will decrease the level or effect of apalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. No initial dose adjustment

• apixaban

  Monitor Closely (1)efavirenz will decrease the level or effect of apixaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• apomorphine

  Monitor Closely (1)efavirenz and apomorphine both increase QTc interval. Use Caution/Monitor.

• apremilast

  Serious - Use Alternative (1)efavirenz 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)efavirenz will decrease the level or effect of aprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)aprepitant will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• arformoterol

  Monitor Closely (1)efavirenz and arformoterol both increase QTc interval. Use Caution/Monitor.

• aripiprazole

  Monitor Closely (2)efavirenz will decrease the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and aripiprazole both increase QTc interval. Use Caution/Monitor.

• armodafinil

  Minor (2)armodafinil will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  efavirenz will decrease the level or effect of armodafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• arsenic trioxide

  Monitor Closely (1)efavirenz and arsenic trioxide both increase QTc interval. Use Caution/Monitor.

• artemether

  Serious - Use Alternative (1)efavirenz and artemether both increase QTc interval. Avoid or Use Alternate Drug.

• artemether/lumefantrine

  Serious - Use Alternative (2)efavirenz will decrease the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong CYP3A4 inducers can result in decreased serum concentrations and loss of antimalarial efficacy
  
  efavirenz and artemether/lumefantrine both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)artemether/lumefantrine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• asenapine

  Monitor Closely (1)asenapine and efavirenz both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and asenapine both increase QTc interval. Avoid or Use Alternate Drug.

• asenapine transdermal

  Monitor Closely (1)asenapine transdermal and efavirenz both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)asenapine transdermal and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• atazanavir

  Monitor Closely (1)atazanavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz will decrease the level or effect of atazanavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (2)atazanavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  efavirenz decreases levels of atazanavir by unspecified interaction mechanism. Minor/Significance Unknown. May be coadministered; see atazanavir monograph for dosing info.

• atogepant

  Monitor Closely (1)efavirenz 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.

• atomoxetine

  Monitor Closely (1)efavirenz and atomoxetine both increase QTc interval. Use Caution/Monitor.

• atorvastatin

  Monitor Closely (1)efavirenz will decrease the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• atovaquone

  Serious - Use Alternative (1)efavirenz decreases levels of atovaquone by unspecified interaction mechanism. Avoid or Use Alternate Drug.

• avanafil

  Monitor Closely (1)efavirenz will decrease the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; increased levels may result in increased associated adverse events; the maximum recommended dose of STENDRA is 50 mg, not to exceed once every 24 hours for patients taking concomitant moderate CYP3A4 inhibitors

• avapritinib

  Monitor Closely (1)efavirenz will decrease the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• axitinib

  Serious - Use Alternative (1)efavirenz 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.

• azithromycin

  Serious - Use Alternative (1)efavirenz and azithromycin both increase QTc interval. Avoid or Use Alternate Drug.

• bazedoxifene/conjugated estrogens

  Monitor Closely (1)efavirenz will decrease the level or effect of bazedoxifene/conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• bedaquiline

  Serious - Use Alternative (2)efavirenz 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
  
  efavirenz and bedaquiline both increase QTc interval. Avoid or Use Alternate Drug.

• belumosudil

  Monitor Closely (1)efavirenz will increase 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)belzutifan will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If unable to avoid coadministration of belzutifan with sensitive CYP3A4 substrates, consider increasing the sensitive CYP3A4 substrate dose in accordance with its prescribing information.

• benzhydrocodone/acetaminophen

  Monitor Closely (1)efavirenz 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.

• betibeglogene autotemcel

  Serious - Use Alternative (1)efavirenz, betibeglogene autotemcel. Other (see comment). Avoid or Use Alternate Drug. Comment: Do not take antiretroviral medications for at least 1 month before mobilization or expected duration for elimination of the medications, and until all cycles of apheresis are completed. Antiretroviral medications may interfere with manufacturing of apheresed cells.

• bortezomib

  Monitor Closely (1)efavirenz will decrease the level or effect of bortezomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• bosentan

  Monitor Closely (1)efavirenz will increase the level or effect of bosentan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.Minor (2)bosentan will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
  
  efavirenz will decrease the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• bosutinib

  Serious - Use Alternative (1)efavirenz 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 (1)efavirenz will decrease the level or effect of brentuximab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• brexanolone

  Monitor Closely (1)brexanolone, efavirenz. Either increases toxicity of the other by sedation. Use Caution/Monitor.

• brexpiprazole

  Monitor Closely (1)efavirenz 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.

• brigatinib

  Serious - Use Alternative (1)efavirenz 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.

• bromocriptine

  Serious - Use Alternative (1)efavirenz increases levels of bromocriptine by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.

• buprenorphine

  Monitor Closely (1)efavirenz will decrease the level or effect of buprenorphine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and buprenorphine both increase QTc interval. Avoid or Use Alternate Drug.

• buprenorphine buccal

  Monitor Closely (1)efavirenz will decrease the level or effect of buprenorphine buccal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)buprenorphine buccal and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• buprenorphine subdermal implant

  Monitor Closely (1)efavirenz 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.Serious - Use Alternative (1)buprenorphine subdermal implant and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• buprenorphine transdermal

  Serious - Use Alternative (2)efavirenz will decrease the level or effect of buprenorphine transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  buprenorphine transdermal and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• buprenorphine, long-acting injection

  Monitor Closely (1)efavirenz 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.Serious - Use Alternative (1)buprenorphine, long-acting injection and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• bupropion

  Monitor Closely (1)efavirenz will decrease the level or effect of bupropion by increasing metabolism. Use Caution/Monitor. Coadministration with hepatic inducers reduced bupropion AUC and Cmax; hydroxybupropion (active metabolite) Cmax was increased

• buspirone

  Monitor Closely (1)efavirenz will decrease the level or effect of buspirone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• butabarbital

  Minor (1)butabarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• butalbital

  Minor (1)butalbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• cabazitaxel

  Monitor Closely (1)efavirenz will increase the level or effect of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution should be exercised with concomitant use of moderate CYP3A4 inhibitors.

• cabergoline

  Serious - Use Alternative (1)efavirenz increases levels of cabergoline by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.

• cabotegravir

  Serious - Use Alternative (1)efavirenz, cabotegravir. Other (see comment). Avoid or Use Alternate Drug. Comment: Cabotegravir plus rilpivirine is a complete regimen. Coadministration with other antiretroviral medications for treating HIV-1 infection is not recommended.

• cabozantinib

  Serious - Use Alternative (1)efavirenz 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.

• calcifediol

  Monitor Closely (1)efavirenz, calcifediol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Drugs that stimulate microsomal hydroxylation reduce the half-life of calcifediol.

• calcitriol

  Monitor Closely (1)efavirenz will decrease the level or effect of calcitriol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cannabidiol

  Monitor Closely (3)efavirenz 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 moderate CYP2C19 inhibitor.
  
  efavirenz 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.
  
  cannabidiol, efavirenz. 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.

• capmatinib

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of capmatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• carbamazepine

  Contraindicated (1)carbamazepine, efavirenz. Either decreases levels of the other by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of carbamazepine with NNRTIs may result in a loss of virologic response and possible resistance to the NNRTI. A decrease in AUC is observed for both carbamazepine (27%) and efavirenz (36%) when coadministered.Monitor Closely (1)carbamazepine will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.

• cariprazine

  Contraindicated (1)efavirenz 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.

• carvedilol

  Serious - Use Alternative (1)efavirenz will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.

• caspofungin

  Minor (1)efavirenz decreases levels of caspofungin by increasing metabolism. Minor/Significance Unknown.

• celecoxib

  Monitor Closely (1)efavirenz will increase the level or effect of celecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• cenobamate

  Monitor Closely (3)cenobamate, efavirenz. Either increases levels of the other by sedation. Use Caution/Monitor.
  
  cenobamate will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP2B6 substrate, as needed, when coadministered with cenobamate.
  
  cenobamate will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.

• ceritinib

  Serious - Use Alternative (3)efavirenz decreases levels of ceritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and ceritinib both increase QTc interval. Avoid or Use Alternate Drug.
  
  ceritinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• cevimeline

  Minor (1)efavirenz will decrease the level or effect of cevimeline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• chlordiazepoxide

  Monitor Closely (1)efavirenz will decrease the level or effect of chlordiazepoxide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• chloroquine

  Monitor Closely (1)efavirenz will decrease the level or effect of chloroquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and chloroquine both increase QTc interval. Avoid or Use Alternate Drug.

• chlorpheniramine

  Monitor Closely (1)efavirenz will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• chlorpromazine

  Serious - Use Alternative (1)efavirenz and chlorpromazine both increase QTc interval. Avoid or Use Alternate Drug.

• cilostazol

  Monitor Closely (2)efavirenz will decrease the level or effect of cilostazol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz increases toxicity of cilostazol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider decreasing cilostazol dose; moderate CYP2C19 inhibitors may increase serum levels of 3,4-dehydrocilostazol (active metabolite).

• cimetidine

  Minor (1)efavirenz will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• cinacalcet

  Monitor Closely (1)efavirenz will decrease the level or effect of cinacalcet by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ciprofloxacin

  Monitor Closely (1)efavirenz and ciprofloxacin both increase QTc interval. Use Caution/Monitor.

• cisapride

  Monitor Closely (1)efavirenz and cisapride both increase QTc interval. Use Caution/Monitor.

• citalopram

  Serious - Use Alternative (2)efavirenz will decrease the level or effect of citalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and citalopram both increase QTc interval. Avoid or Use Alternate Drug.

• clarithromycin

  Monitor Closely (1)clarithromycin will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and clarithromycin both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)efavirenz will decrease the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• clobazam

  Monitor Closely (2)efavirenz 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).
  
  efavirenz, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression).

• clomipramine

  Monitor Closely (1)efavirenz and clomipramine both increase QTc interval. Use Caution/Monitor.Minor (1)efavirenz will decrease the level or effect of clomipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• clonazepam

  Monitor Closely (1)efavirenz will decrease the level or effect of clonazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clopidogrel

  Monitor Closely (1)efavirenz decreases effects of clopidogrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Clopidogrel efficacy may be reduced by drugs that inhibit CYP3A4. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. Clopidogrel is metabolized to this active metabolite in part by CYP3A4. .Serious - Use Alternative (1)efavirenz decreases effects of clopidogrel by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Clopidogrel efficacy may be reduced by drugs that inhibit CYP2C19. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. Clopidogrel is metabolized to this active metabolite in part by CYP2C19. .

• clorazepate

  Monitor Closely (1)efavirenz will decrease the level or effect of clorazepate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clozapine

  Monitor Closely (2)efavirenz will decrease the level or effect of clozapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and clozapine both increase QTc interval. Use Caution/Monitor.

• cobicistat

  Monitor Closely (1)cobicistat will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)efavirenz will decrease the level or effect of cobicistat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with efavirenz may result in loss of therapeutic effect and development of resistance to cobicistat.

• cobimetinib

  Contraindicated (1)efavirenz 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.

• cocaine topical

  Minor (1)efavirenz will increase the level or effect of cocaine topical by affecting hepatic enzyme CYP2B6 metabolism. Minor/Significance Unknown.

• colchicine

  Minor (1)efavirenz will decrease the level or effect of colchicine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• conivaptan

  Monitor Closely (1)efavirenz will decrease the level or effect of conivaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)conivaptan will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• conjugated estrogens

  Monitor Closely (1)efavirenz will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• conjugated estrogens, vaginal

  Monitor Closely (1)efavirenz will decrease the level or effect of conjugated estrogens, vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• copanlisib

  Serious - Use Alternative (1)efavirenz 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

  Monitor Closely (1)efavirenz will decrease the level or effect of cortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)cortisone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• crizotinib

  Monitor Closely (1)efavirenz increases levels of crizotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution should be exercised with concomitant use of moderate CYP3A inhibitors. .Serious - Use Alternative (1)efavirenz and crizotinib both increase QTc interval. Avoid or Use Alternate Drug.

• crofelemer

  Monitor Closely (1)crofelemer increases levels of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.

• cyclophosphamide

  Monitor Closely (1)efavirenz will decrease the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)cyclophosphamide will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• cyclosporine

  Monitor Closely (1)efavirenz will decrease the level or effect of cyclosporine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Closely monitor cyclosporine concentrations when starting, stopping, or adjusting dose of concurrent efavirez, especially within first 2 weeks.Minor (1)cyclosporine will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• dabrafenib

  Monitor Closely (1)dabrafenib will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.Serious - Use Alternative (1)efavirenz decreases levels of dabrafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dantrolene

  Monitor Closely (1)efavirenz will decrease the level or effect of dantrolene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dapsone

  Monitor Closely (1)efavirenz will decrease the level or effect of dapsone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• daridorexant

  Monitor Closely (1)efavirenz and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment. Serious - Use Alternative (1)efavirenz will decrease the level or effect of daridorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• darifenacin

  Monitor Closely (1)efavirenz will decrease the level or effect of darifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)darifenacin will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• darolutamide

  Serious - Use Alternative (1)efavirenz 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

  Monitor Closely (1)darunavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz will decrease the level or effect of darunavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with efavirenz may result in loss of therapeutic effect and development of resistance to darunavirMinor (1)darunavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• dasatinib

  Monitor Closely (2)efavirenz will decrease the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and dasatinib both increase QTc interval. Use Caution/Monitor.Minor (1)dasatinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• deferasirox

  Monitor Closely (1)deferasirox will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• deflazacort

  Serious - Use Alternative (1)efavirenz 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.

• degarelix

  Monitor Closely (1)efavirenz and degarelix both increase QTc interval. Use Caution/Monitor.

• desipramine

  Monitor Closely (1)efavirenz and desipramine both increase QTc interval. Use Caution/Monitor.

• deutetrabenazine

  Monitor Closely (1)efavirenz and deutetrabenazine both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).

• dexamethasone

  Monitor Closely (1)efavirenz will decrease the level or effect of dexamethasone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)dexamethasone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• DHEA, herbal

  Minor (1)DHEA, herbal will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• diazepam

  Monitor Closely (1)efavirenz will decrease the level or effect of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)efavirenz will increase the level or effect of diazepam by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• diazepam intranasal

  Monitor Closely (2)efavirenz 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.
  
  efavirenz 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.

• diclofenac

  Monitor Closely (1)efavirenz will increase the level or effect of diclofenac by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• didanosine

  Monitor Closely (1)didanosine, efavirenz. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Concomitant administration increases risk of liver toxicity.

• dienogest/estradiol valerate

  Contraindicated (1)efavirenz will decrease the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Women should not choose estradiol valerate/dienogest as their contraceptive while using strong CYP3A4 inducers due to potential decrease in contraceptive efficacy. Estradiol valerate/dienogest should not be used for at least 28 days after discontinuation of the inducer due to possibility of decreased contraceptive efficacy.

• difelikefalin

  Monitor Closely (1)difelikefalin and efavirenz both increase sedation. Use Caution/Monitor.

• dihydroergotamine

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of dihydroergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• dihydroergotamine intranasal

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of dihydroergotamine intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• diltiazem

  Monitor Closely (1)efavirenz will decrease the level or effect of diltiazem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• disopyramide

  Serious - Use Alternative (1)efavirenz and disopyramide both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)efavirenz will decrease the level or effect of disopyramide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• docetaxel

  Monitor Closely (1)efavirenz will decrease the level or effect of docetaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dofetilide

  Serious - Use Alternative (1)efavirenz and dofetilide both increase QTc interval. Avoid or Use Alternate Drug.

• dolasetron

  Monitor Closely (1)efavirenz and dolasetron both increase QTc interval. Use Caution/Monitor.

• dolutegravir

  Serious - Use Alternative (1)efavirenz 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)efavirenz will decrease the level or effect of donepezil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• doravirine

  Contraindicated (1)efavirenz 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.

• doxepin

  Monitor Closely (1)efavirenz and doxepin both increase QTc interval. Use Caution/Monitor.

• doxorubicin

  Monitor Closely (1)efavirenz will decrease the level or effect of doxorubicin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• doxorubicin liposomal

  Monitor Closely (1)efavirenz will decrease the level or effect of doxorubicin liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dronabinol

  Monitor Closely (1)efavirenz will increase the level or effect of dronabinol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dronabinol is a CYP3A4 substrate.

• dronedarone

  Contraindicated (1)efavirenz and dronedarone both increase QTc interval. Contraindicated.Monitor Closely (1)dronedarone will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. May decrease dronedarone levels.Serious - Use Alternative (1)efavirenz will decrease the level or effect of dronedarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• droperidol

  Serious - Use Alternative (1)efavirenz and droperidol both increase QTc interval. Avoid or Use Alternate Drug.

• dutasteride

  Minor (1)efavirenz will decrease the level or effect of dutasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• duvelisib

  Serious - Use Alternative (1)efavirenz 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.

• elacestrant

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• elagolix

  Monitor Closely (2)efavirenz will decrease the level or effect of elagolix by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  elagolix will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed.

• elbasvir/grazoprevir

  Contraindicated (1)efavirenz 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

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of eletriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• eliglustat

  Monitor Closely (2)efavirenz will decrease the level or effect of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A inducers significantly decreases eliglustat exposure; coadministration not recommended
  
  efavirenz and eliglustat both increase QTc interval. Use Caution/Monitor.

• elivaldogene autotemcel

  Serious - Use Alternative (1)elivaldogene autotemcel, efavirenz. Either decreases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Patients should not take antiretroviral medications for at least 1 month before initiating medications for stem cell mobilization, for the duration of the medications? elimination, and until all cycles of apheresis are completed.

• eltrombopag

  Serious - Use Alternative (1)efavirenz will increase the level or effect of eltrombopag by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.

• elvitegravir

  Serious - Use Alternative (1)efavirenz 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)efavirenz, elvitegravir/cobicistat/emtricitabine/tenofovir DF. Other (see comment). Contraindicated. Comment: Elvitegravir/cobicistat/emtricitabine/tenofovir is a complete regimen for HIV and should not be administered with other antiretrovirals.Serious - Use Alternative (1)efavirenz will decrease the level or effect of elvitegravir/cobicistat/emtricitabine/tenofovir DF by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• emtricitabine

  Monitor Closely (1)efavirenz and emtricitabine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• encorafenib

  Monitor Closely (1)encorafenib, efavirenz. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.Serious - Use Alternative (3)efavirenz and encorafenib both increase QTc interval. Avoid or Use Alternate Drug.
  
  efavirenz will decrease the level or effect of encorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  encorafenib and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• enfuvirtide

  Monitor Closely (1)efavirenz and enfuvirtide both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• entrectinib

  Serious - Use Alternative (2)efavirenz will decrease the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and entrectinib both increase QTc interval. Avoid or Use Alternate Drug.

• enzalutamide

  Serious - Use Alternative (2)efavirenz will decrease the level or effect of enzalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  enzalutamide will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• eplerenone

  Minor (1)efavirenz will decrease the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• erdafitinib

  Serious - Use Alternative (2)efavirenz will decrease the level or effect of erdafitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz will increase the level or effect of erdafitinib by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. If coadministration of a strong CYP2C9 inhibitors is unavoidable, closely monitor adverse reactions and modify dose of erdafitinib accordingly. If strong CYP2C9 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities.

• ergoloid mesylates

  Serious - Use Alternative (1)efavirenz increases levels of ergoloid mesylates by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.

• ergonovine

  Contraindicated (1)efavirenz will decrease the level or effect of ergonovine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• ergotamine

  Serious - Use Alternative (2)efavirenz will decrease the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  efavirenz increases levels of ergotamine by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.

• eribulin

  Serious - Use Alternative (1)efavirenz and eribulin both increase QTc interval. Avoid or Use Alternate Drug.

• erlotinib

  Monitor Closely (1)efavirenz will decrease the level or effect of erlotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• erythromycin base

  Monitor Closely (1)erythromycin base will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)efavirenz will decrease the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  efavirenz and erythromycin base both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin ethylsuccinate

  Monitor Closely (1)erythromycin ethylsuccinate will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)efavirenz will decrease the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  efavirenz and erythromycin ethylsuccinate both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin lactobionate

  Monitor Closely (1)erythromycin lactobionate will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)efavirenz will decrease the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  efavirenz and erythromycin lactobionate both increase QTc interval. Avoid or Use Alternate Drug.

• erythromycin stearate

  Monitor Closely (1)erythromycin stearate will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)efavirenz will decrease the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  efavirenz and erythromycin stearate both increase QTc interval. Avoid or Use Alternate Drug.

• escitalopram

  Monitor Closely (3)efavirenz will increase the level or effect of escitalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of escitalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and escitalopram both increase QTc interval. Use Caution/Monitor.

• esketamine intranasal

  Monitor Closely (1)esketamine intranasal, efavirenz. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.

• eslicarbazepine acetate

  Monitor Closely (1)eslicarbazepine acetate will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• esomeprazole

  Monitor Closely (1)efavirenz will decrease the level or effect of esomeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)efavirenz will increase the level or effect of esomeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• estradiol

  Monitor Closely (1)efavirenz will decrease the level or effect of estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• estradiol vaginal

  Monitor Closely (1)efavirenz 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)efavirenz will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• estrogens esterified

  Monitor Closely (1)efavirenz will decrease the level or effect of estrogens esterified by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• estropipate

  Monitor Closely (1)efavirenz will decrease the level or effect of estropipate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• eszopiclone

  Monitor Closely (1)efavirenz will decrease the level or effect of eszopiclone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ethinylestradiol

  Serious - Use Alternative (1)efavirenz 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.

• ethosuximide

  Monitor Closely (1)efavirenz will decrease the level or effect of ethosuximide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ethotoin

  Serious - Use Alternative (1)efavirenz will increase the level or effect of ethotoin by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.

• etonogestrel

  Monitor Closely (1)efavirenz will decrease the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• etoposide

  Monitor Closely (1)efavirenz will decrease the level or effect of etoposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• etravirine

  Contraindicated (1)efavirenz decreases levels of etravirine by increasing metabolism. Contraindicated. Mfr.'s PI recommends not combining etravirine with other NNRTIs.Monitor Closely (2)efavirenz will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.Minor (1)etravirine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• eucalyptus

  Minor (1)efavirenz will decrease the level or effect of eucalyptus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• everolimus

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of everolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• exemestane

  Monitor Closely (1)efavirenz 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

  Monitor Closely (1)fedratinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.Serious - Use Alternative (1)efavirenz 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.

• felbamate

  Monitor Closely (1)efavirenz will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• felodipine

  Monitor Closely (1)efavirenz will decrease the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fentanyl

  Monitor Closely (1)efavirenz 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.

• fentanyl intranasal

  Monitor Closely (1)efavirenz 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

  Monitor Closely (1)efavirenz 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

  Monitor Closely (1)efavirenz 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.

• fesoterodine

  Monitor Closely (1)efavirenz will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fexinidazole

  Serious - Use Alternative (4)efavirenz 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.
  
  fexinidazole will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug. Coadministration may decrease plasma concentrations of CYP2B6 substrates owing to fexinidazole inducing CYP2B6.
  
  fexinidazole and efavirenz both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval.
  
  fexinidazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates.

• finasteride

  Minor (1)efavirenz will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• finerenone

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fingolimod

  Serious - Use Alternative (1)fingolimod and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.

• flecainide

  Serious - Use Alternative (1)efavirenz and flecainide both increase QTc interval. Avoid or Use Alternate Drug.

• flibanserin

  Monitor Closely (1)efavirenz 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.

• fluconazole

  Monitor Closely (1)efavirenz and fluconazole both increase QTc interval. Use Caution/Monitor.Minor (1)fluconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• fludrocortisone

  Monitor Closely (1)efavirenz will decrease the level or effect of fludrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)fludrocortisone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• fluoxetine

  Monitor Closely (1)efavirenz and fluoxetine both increase QTc interval. Use Caution/Monitor.

• fluphenazine

  Monitor Closely (1)efavirenz and fluphenazine both increase QTc interval. Use Caution/Monitor.

• flurazepam

  Monitor Closely (1)efavirenz will decrease the level or effect of flurazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• flurbiprofen

  Monitor Closely (1)efavirenz will increase the level or effect of flurbiprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• fluvastatin

  Monitor Closely (1)efavirenz will increase the level or effect of fluvastatin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• fluvoxamine

  Monitor Closely (2)fluvoxamine will increase the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
  
  efavirenz and fluvoxamine both increase QTc interval. Use Caution/Monitor.

• formoterol

  Monitor Closely (1)efavirenz and formoterol both increase QTc interval. Use Caution/Monitor.

• fosamprenavir

  Monitor Closely (2)efavirenz will decrease the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  fosamprenavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.Minor (1)fosamprenavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• fosaprepitant

  Monitor Closely (1)efavirenz will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)fosaprepitant will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• foscarnet

  Serious - Use Alternative (1)efavirenz and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.

• fosphenytoin

  Serious - Use Alternative (1)efavirenz will increase the level or effect of fosphenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.Minor (1)fosphenytoin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• fostamatinib

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of fostamatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• fostemsavir

  Contraindicated (1)efavirenz 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.Monitor Closely (1)efavirenz and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.

• galantamine

  Minor (1)efavirenz will decrease the level or effect of galantamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ganaxolone

  Monitor Closely (1)efavirenz and ganaxolone both increase sedation. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz 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.

• gefitinib

  Monitor Closely (1)efavirenz 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.

• gemifloxacin

  Monitor Closely (1)efavirenz and gemifloxacin both increase QTc interval. Use Caution/Monitor.

• gemtuzumab

  Serious - Use Alternative (1)efavirenz and gemtuzumab both increase QTc interval. Avoid or Use Alternate Drug.

• gilteritinib

  Monitor Closely (1)efavirenz and gilteritinib both increase QTc interval. Use Caution/Monitor.

• glasdegib

  Serious - Use Alternative (2)efavirenz 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.
  
  efavirenz and glasdegib both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, monitor for increased risk of QTc interval prolongation.

• glecaprevir/pibrentasvir

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of glecaprevir/pibrentasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of efavirenz (a strong CYP3A4 inducer) with glecaprevir/pibrentasvir may significantly decrease glecaprevir/pibrentasvir plasma concentrations and AUC. Potential for loss of therapeutic effect.

• goserelin

  Monitor Closely (1)efavirenz and goserelin both increase QTc interval. Use Caution/Monitor.

• granisetron

  Monitor Closely (1)efavirenz and granisetron both increase QTc interval. Use Caution/Monitor.

• grapefruit

  Minor (1)grapefruit will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• griseofulvin

  Minor (1)griseofulvin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• guanfacine

  Monitor Closely (1)efavirenz 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)efavirenz will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and haloperidol both increase QTc interval. Use Caution/Monitor.

• histrelin

  Monitor Closely (1)efavirenz and histrelin both increase QTc interval. Use Caution/Monitor.

• hydrocodone

  Monitor Closely (1)efavirenz 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

• hydrocortisone

  Monitor Closely (1)efavirenz will decrease the level or effect of hydrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)hydrocortisone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• hydroxychloroquine sulfate

  Serious - Use Alternative (1)efavirenz and hydroxychloroquine sulfate both increase QTc interval. Avoid or Use Alternate Drug.

• hydroxyprogesterone caproate

  Monitor Closely (1)efavirenz will decrease the level or effect of hydroxyprogesterone caproate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• hydroxyzine

  Monitor Closely (1)efavirenz and hydroxyzine both increase QTc interval. Use Caution/Monitor.

• ibrutinib

  Serious - Use Alternative (1)efavirenz 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.

• ibuprofen

  Monitor Closely (1)efavirenz will increase the level or effect of ibuprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• ibuprofen IV

  Monitor Closely (1)efavirenz will increase the level or effect of ibuprofen IV by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• ibutilide

  Serious - Use Alternative (1)efavirenz and ibutilide both increase QTc interval. Avoid or Use Alternate Drug.

• idelalisib

  Serious - Use Alternative (2)efavirenz 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
  
  idelalisib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates

• ifosfamide

  Monitor Closely (2)efavirenz 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.
  
  efavirenz 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.

• iloperidone

  Monitor Closely (2)efavirenz will decrease the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  iloperidone increases levels of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4.Serious - Use Alternative (1)efavirenz and iloperidone both increase QTc interval. Avoid or Use Alternate Drug.

• imatinib

  Minor (1)efavirenz will decrease the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• imipramine

  Monitor Closely (2)efavirenz will increase the level or effect of imipramine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  efavirenz and imipramine both increase QTc interval. Use Caution/Monitor.Minor (1)efavirenz will decrease the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• indacaterol, inhaled

  Monitor Closely (1)efavirenz and indacaterol, inhaled both increase QTc interval. Use Caution/Monitor.

• indinavir

  Monitor Closely (1)indinavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz will decrease the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)indinavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• infigratinib

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• inotuzumab

  Serious - Use Alternative (1)efavirenz and inotuzumab both increase QTc interval. Avoid or Use Alternate Drug.

• irinotecan

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• irinotecan liposomal

  Serious - Use Alternative (1)efavirenz 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)efavirenz will decrease the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• isoflurane

  Serious - Use Alternative (1)efavirenz and isoflurane both increase QTc interval. Avoid or Use Alternate Drug.

• isoniazid

  Monitor Closely (1)isoniazid will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isosorbide dinitrate

  Monitor Closely (1)efavirenz will decrease the level or effect of isosorbide dinitrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isosorbide mononitrate

  Monitor Closely (1)efavirenz will decrease the level or effect of isosorbide mononitrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isradipine

  Monitor Closely (2)efavirenz will decrease the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and isradipine both increase QTc interval. Use Caution/Monitor.

• istradefylline

  Monitor Closely (1)istradefylline will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.Serious - Use Alternative (1)efavirenz 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

  Serious - Use Alternative (3)itraconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Not recommended 2 weeks before and during itraconazole.
  
  efavirenz will decrease the level or effect of itraconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Not recommended 2 weeks before and during itraconazole.
  
  efavirenz and itraconazole both increase QTc interval. Avoid or Use Alternate Drug.

• ivabradine

  Serious - Use Alternative (1)efavirenz 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 (1)efavirenz will decrease the level or effect of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz, ivacaftor. Other (see comment). Avoid or Use Alternate Drug. Comment: Efavirenz decreases levels of ivacaftor by CYP enzyme induction; whereas, ivacaftor increases levels of efavirenz by inhibiting CYP3A4 .

• ivosidenib

  Monitor Closely (1)ivosidenib will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)efavirenz 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.
  
  efavirenz and ivosidenib both decrease QTc interval. Avoid or Use Alternate Drug.

• ixabepilone

  Monitor Closely (1)efavirenz will decrease the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ixazomib

  Serious - Use Alternative (1)efavirenz 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%.

• ketamine

  Monitor Closely (2)efavirenz will increase the level or effect of ketamine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of ketamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ketoconazole

  Monitor Closely (1)ketoconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)efavirenz will decrease the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• lamivudine

  Monitor Closely (1)efavirenz and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• lansoprazole

  Monitor Closely (1)efavirenz will decrease the level or effect of lansoprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)efavirenz will increase the level or effect of lansoprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• lapatinib

  Monitor Closely (2)efavirenz will decrease the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and lapatinib both increase QTc interval. Use Caution/Monitor.Minor (1)lapatinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• larotrectinib

  Serious - Use Alternative (1)efavirenz 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-livesMinor (1)larotrectinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• lasmiditan

  Monitor Closely (1)lasmiditan, efavirenz. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.

• lefamulin

  Contraindicated (1)lefamulin will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lefamulin is contraindicated with CYP3A substrates know to prolong the QT interval.Serious - Use Alternative (1)efavirenz and lefamulin both increase QTc interval. Avoid or Use Alternate Drug.

• lemborexant

  Monitor Closely (1)lemborexant will decrease the level or effect of efavirenz 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 (1)efavirenz will decrease the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lenacapavir

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of lenacapavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lenacapavir with moderate CYP3A4 inducers.

• lenvatinib

  Serious - Use Alternative (1)efavirenz and lenvatinib both increase QTc interval. Avoid or Use Alternate Drug.

• letermovir

  Monitor Closely (1)letermovir increases levels of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz 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.

• leuprolide

  Monitor Closely (1)efavirenz and leuprolide both increase QTc interval. Use Caution/Monitor.

• levalbuterol

  Monitor Closely (1)efavirenz and levalbuterol both increase QTc interval. Use Caution/Monitor.

• levamlodipine

  Monitor Closely (1)efavirenz will decrease the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No information is available on the quantitative effects of CYP3A4 inducers on amlodipine. Closely monitor blood pressure when amlodipine is coadministered with CYP3A4 inducers.

• levofloxacin

  Monitor Closely (1)efavirenz and levofloxacin both increase QTc interval. Use Caution/Monitor.

• levoketoconazole

  Monitor Closely (1)levoketoconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)efavirenz will decrease the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• levonorgestrel intrauterine

  Monitor Closely (1)efavirenz decreases levels of levonorgestrel intrauterine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• levonorgestrel oral

  Monitor Closely (1)efavirenz decreases levels of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  Monitor Closely (1)efavirenz 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.

• linagliptin

  Monitor Closely (2)efavirenz 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.
  
  efavirenz will decrease the level or effect of linagliptin by Other (see comment). Use Caution/Monitor. Reports of hyperglycemia due to insulin resistance with protease inhibitors.

• lithium

  Monitor Closely (1)efavirenz and lithium both increase QTc interval. Use Caution/Monitor.

• lofexidine

  Serious - Use Alternative (1)efavirenz and lofexidine both increase QTc interval. Avoid or Use Alternate Drug.

• lomitapide

  Contraindicated (1)efavirenz increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Increases lomitapide levels several folds.

• lonafarnib

  Contraindicated (1)efavirenz 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.

• loperamide

  Monitor Closely (1)efavirenz and loperamide both increase QTc interval. Use Caution/Monitor.

• lopinavir

  Monitor Closely (1)efavirenz will decrease the level or effect of lopinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)lopinavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and lopinavir both increase QTc interval. Avoid or Use Alternate Drug.

• loratadine

  Monitor Closely (1)efavirenz will decrease the level or effect of loratadine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lorlatinib

  Contraindicated (1)efavirenz 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)lorlatinib will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• losartan

  Monitor Closely (2)efavirenz will increase the level or effect of losartan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.
  
  efavirenz will decrease the level or effect of losartan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)efavirenz decreases effects of losartan by decreasing metabolism. Minor/Significance Unknown. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.

• lovastatin

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lumacaftor/ivacaftor

  Contraindicated (1)efavirenz 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 (1)lumacaftor/ivacaftor, efavirenz. affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2B6 substrates. .

• lumateperone

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• lumefantrine

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong CYP3A4 inducers can result in decreased serum concentrations and loss of antimalarial efficacyMinor (1)lumefantrine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• lurasidone

  Monitor Closely (2)lurasidone, efavirenz. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity.
  
  efavirenz decreases levels of lurasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. It may be necessary to increase the lurasidone dose after chronic treatment (ie, 7 days or more) with moderate CYP3A inducers.

• lurbinectedin

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• macimorelin

  Serious - Use Alternative (2)efavirenz 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.
  
  efavirenz and macimorelin both increase QTc interval. Avoid or Use Alternate Drug.

• macitentan

  Serious - Use Alternative (1)efavirenz 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

• maprotiline

  Monitor Closely (1)efavirenz and maprotiline both increase QTc interval. Use Caution/Monitor.

• maraviroc

  Monitor Closely (1)efavirenz will decrease the level or effect of maraviroc by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• marijuana

  Monitor Closely (1)efavirenz will decrease the level or effect of marijuana by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)marijuana will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• mavacamten

  Contraindicated (2)efavirenz 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.
  
  efavirenz will decrease the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• medroxyprogesterone

  Monitor Closely (1)efavirenz will decrease the level or effect of medroxyprogesterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• mefloquine

  Monitor Closely (2)efavirenz will decrease the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and mefloquine both increase QTc interval. Use Caution/Monitor.

• meloxicam

  Monitor Closely (1)efavirenz will increase the level or effect of meloxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• meperidine

  Monitor Closely (1)efavirenz will decrease the level or effect of meperidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased toxic metabolite formation.

• mestranol

  Monitor Closely (1)efavirenz will decrease the level or effect of mestranol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• metaxalone

  Monitor Closely (1)efavirenz will decrease the level or effect of metaxalone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• methadone

  Monitor Closely (1)efavirenz will decrease the level or effect of methadone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and methadone both increase QTc interval. Avoid or Use Alternate Drug.

• methylergonovine

  Serious - Use Alternative (1)efavirenz increases levels of methylergonovine by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.

• methylprednisolone

  Monitor Closely (1)efavirenz will decrease the level or effect of methylprednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)methylprednisolone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• metoclopramide intranasal

  Serious - Use Alternative (1)efavirenz, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.

• metronidazole

  Minor (1)metronidazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• miconazole vaginal

  Minor (1)miconazole vaginal will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• midazolam

  Monitor Closely (1)efavirenz will decrease the level or effect of midazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• midazolam intranasal

  Monitor Closely (1)midazolam intranasal, efavirenz. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.

• midostaurin

  Serious - Use Alternative (2)efavirenz 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.
  
  efavirenz and midostaurin both increase QTc interval. Avoid or Use Alternate Drug.

• mifepristone

  Monitor Closely (1)efavirenz, mifepristone. Other (see comment). Use Caution/Monitor. Comment: Efavirenz shown in vitro to induce CYP3A4 and CYP2B6, but in vitro has been shown to inhibit CYP3A4 and therefore may affect mifepristone levels/effect; mifepristone inhibits CYP2B6, therefore increasing exposure of efavirenz.Serious - Use Alternative (3)mifepristone will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz will decrease the level or effect of mifepristone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and mifepristone both increase QTc interval. Avoid or Use Alternate Drug.

• mirtazapine

  Monitor Closely (2)efavirenz and mirtazapine both increase QTc interval. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of mirtazapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• mitotane

  Monitor Closely (1)mitotane decreases levels of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.

• mobocertinib

  Serious - Use Alternative (2)efavirenz will decrease the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and mobocertinib both increase QTc interval. Avoid or Use Alternate Drug.

• modafinil

  Monitor Closely (1)efavirenz will decrease the level or effect of modafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• montelukast

  Minor (1)efavirenz will decrease the level or effect of montelukast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• moxifloxacin

  Serious - Use Alternative (1)efavirenz and moxifloxacin both increase QTc interval. Avoid or Use Alternate Drug.

• nafcillin

  Monitor Closely (1)nafcillin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inducers may increase metabolism of CYP3A4 substrates

• naldemedine

  Monitor Closely (1)efavirenz will decrease the level or effect of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Simulation using physiologically-based pharmacokinetic modeling suggests that concomitant use of moderated CYP3A4 inducers decrease exposure to naldemedine. The clinical consequence of this decreased exposure is unknown.

• naloxegol

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use of naloxegol with strong CYP3A4 inducers is not recommended

• nateglinide

  Serious - Use Alternative (1)efavirenz will increase the level or effect of nateglinide by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.

• nefazodone

  Monitor Closely (1)nefazodone will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz will decrease the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• nelfinavir

  Monitor Closely (2)efavirenz will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.Minor (1)nelfinavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• neratinib

  Serious - Use Alternative (1)efavirenz 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.

• netupitant/palonosetron

  Serious - Use Alternative (1)efavirenz 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

  Contraindicated (1)efavirenz and nevirapine both increase risk of immune reconstitution syndrome. Contraindicated. Coadministration not recommended as this combination has been associated with an increase in adverse reactions and no improvement in efficacySerious - Use Alternative (2)efavirenz will decrease the level or effect of nevirapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  nevirapine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration not recommended as this combination has been associated with an increase in adverse reactions and no improvement in efficacy

• nicardipine

  Monitor Closely (1)efavirenz will decrease the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nifedipine

  Monitor Closely (1)efavirenz will decrease the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.Minor (1)nifedipine will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nilotinib

  Monitor Closely (1)efavirenz will decrease the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and nilotinib both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)nilotinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nimodipine

  Minor (1)efavirenz will decrease the level or effect of nimodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• nirmatrelvir

  Monitor Closely (1)nirmatrelvir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nirmatrelvir/ritonavir

  Monitor Closely (1)nirmatrelvir/ritonavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nisoldipine

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of nisoldipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• nitrendipine

  Minor (1)efavirenz will decrease the level or effect of nitrendipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• norethindrone

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of norethindrone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• norgestrel

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of norgestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• nortriptyline

  Monitor Closely (1)efavirenz and nortriptyline both increase QTc interval. Use Caution/Monitor.

• octreotide

  Monitor Closely (1)efavirenz and octreotide both increase QTc interval. Use Caution/Monitor.

• ofloxacin

  Monitor Closely (1)efavirenz and ofloxacin both increase QTc interval. Use Caution/Monitor.

• olanzapine

  Monitor Closely (1)efavirenz and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances

• olaparib

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with moderate CYP3A inducers cannot be avoided, be aware of a potential for decreased efficacy of olaparib

• oliceridine

  Monitor Closely (1)efavirenz 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.

• olodaterol inhaled

  Monitor Closely (1)efavirenz and olodaterol inhaled both increase QTc interval. Use Caution/Monitor.

• olopatadine intranasal

  Serious - Use Alternative (1)efavirenz and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.

• olutasidenib

  Serious - Use Alternative (1)efavirenz 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 (1)efavirenz will decrease the level or effect of omaveloxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ombitasvir/paritaprevir/ritonavir

  Contraindicated (1)efavirenz will decrease the level or effect of ombitasvir/paritaprevir/ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)

  Contraindicated (2)ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC), efavirenz. unspecified interaction mechanism. Contraindicated. Coadministration of avirenz-based regimens with Viekira Pak was poorly tolerated and resulted in liver enzyme elevations.
  
  efavirenz will decrease the level or effect of ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• omeprazole

  Monitor Closely (2)efavirenz will increase the level or effect of omeprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of omeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ondansetron

  Monitor Closely (1)efavirenz will decrease the level or effect of ondansetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and ondansetron both increase QTc interval. Avoid or Use Alternate Drug.

• orlistat

  Monitor Closely (1)orlistat will decrease the level or effect of efavirenz by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Loss of virological control reported in HIV-infected patients taking orlistat concomitantly. Exact mechanism is unclear, but may include a drug-drug interaction that inhibits systemic absorption of the antiretroviral drug. Monitor HIV RNA levels frequently and if increased HIV viral load confirmed, discontinue orlistat.

• osilodrostat

  Monitor Closely (2)osilodrostat and efavirenz both increase QTc interval. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of osilodrostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor cortisol concentration and patient?s signs and symptoms during coadministration or discontinuation with strong CYP3A4 inducers. Adjust dose of osilodrostat if necessary.

• osimertinib

  Serious - Use Alternative (2)efavirenz 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.
  
  efavirenz and osimertinib both increase QTc interval. Avoid or Use Alternate Drug.

• ospemifene

  Monitor Closely (1)efavirenz decreases levels of ospemifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• oxaliplatin

  Monitor Closely (1)oxaliplatin will increase the level or effect of efavirenz by Other (see comment). Use Caution/Monitor. Monitor for ECG changes if therapy is initiated in patients with drugs known to prolong QT interval.Serious - Use Alternative (1)efavirenz and oxaliplatin both increase QTc interval. Avoid or Use Alternate Drug.

• oxcarbazepine

  Monitor Closely (1)oxcarbazepine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• oxybutynin

  Minor (1)efavirenz will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• oxycodone

  Monitor Closely (1)efavirenz decreases levels of oxycodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ozanimod

  Serious - Use Alternative (1)efavirenz and ozanimod both increase QTc interval. Avoid or Use Alternate Drug.

• paclitaxel

  Minor (1)efavirenz will decrease the level or effect of paclitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• paclitaxel protein bound

  Minor (1)efavirenz will decrease the level or effect of paclitaxel protein bound by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• palbociclib

  Monitor Closely (1)efavirenz will decrease the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• panobinostat

  Contraindicated (1)efavirenz 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.Serious - Use Alternative (1)efavirenz and panobinostat both increase QTc interval. Avoid or Use Alternate Drug.

• pantoprazole

  Minor (1)efavirenz will increase the level or effect of pantoprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.

• parecoxib

  Serious - Use Alternative (1)efavirenz will increase the level or effect of parecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.Minor (1)efavirenz will decrease the level or effect of parecoxib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• paricalcitol

  Monitor Closely (1)efavirenz will decrease the level or effect of paricalcitol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• pasireotide

  Monitor Closely (1)efavirenz and pasireotide both increase QTc interval. Use Caution/Monitor.

• pazopanib

  Monitor Closely (1)efavirenz will decrease the level or effect of pazopanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and pazopanib both increase QTc interval. Avoid or Use Alternate Drug.

• pemigatinib

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• pentamidine

  Serious - Use Alternative (1)efavirenz and pentamidine both increase QTc interval. Avoid or Use Alternate Drug.

• pentobarbital

  Minor (1)pentobarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• perampanel

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of perampanel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• perphenazine

  Monitor Closely (1)efavirenz and perphenazine both increase QTc interval. Use Caution/Monitor.

• pexidartinib

  Serious - Use Alternative (2)efavirenz will decrease the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and pexidartinib both increase Other (see comment). Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity.

• phenobarbital

  Minor (1)phenobarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• phenytoin

  Monitor Closely (3)efavirenz will increase the level or effect of phenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
  
  phenytoin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. When given together, periodic monitoring for reduced efavirenz efficacy and phenytoin plasma concentrations are recommended .
  
  phenytoin will increase the level or effect of efavirenz by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• pimavanserin

  Monitor Closely (1)efavirenz 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)efavirenz and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.

• pimozide

  Monitor Closely (1)efavirenz will decrease the level or effect of pimozide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and pimozide both increase QTc interval. Contraindicated.

• pioglitazone

  Minor (1)efavirenz will decrease the level or effect of pioglitazone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• piroxicam

  Monitor Closely (1)efavirenz will increase the level or effect of piroxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• pitolisant

  Monitor Closely (1)efavirenz 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.Serious - Use Alternative (1)efavirenz and pitolisant both increase QTc interval. Avoid or Use Alternate Drug.

• polatuzumab vedotin

  Monitor Closely (1)efavirenz 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.

• pomalidomide

  Serious - Use Alternative (1)efavirenz decreases levels of pomalidomide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• ponatinib

  Minor (1)efavirenz decreases levels of ponatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. Avoid unless the coadministration outweighs the possible risk of ponatinib underexposure; monitor for signs of reduced efficacy.

• ponesimod

  Serious - Use Alternative (1)efavirenz and ponesimod both increase QTc interval. Avoid or Use Alternate Drug.

• posaconazole

  Contraindicated (1)efavirenz and posaconazole both increase QTc interval. Contraindicated.Minor (1)posaconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• pralsetinib

  Serious - Use Alternative (1)efavirenz 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.

• praziquantel

  Contraindicated (1)efavirenz decreases levels of praziquantel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP450 inducers significantly decrease praziquantel blood levels.

• prednisolone

  Monitor Closely (1)efavirenz will decrease the level or effect of prednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• prednisone

  Monitor Closely (1)efavirenz will decrease the level or effect of prednisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)prednisone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• pretomanid

  Serious - Use Alternative (2)efavirenz 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.
  
  efavirenz, 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.

• primaquine

  Monitor Closely (2)efavirenz will decrease the level or effect of primaquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and primaquine both increase QTc interval. Use Caution/Monitor.

• primidone

  Minor (1)primidone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• procainamide

  Serious - Use Alternative (1)efavirenz and procainamide both increase QTc interval. Avoid or Use Alternate Drug.

• prochlorperazine

  Monitor Closely (1)efavirenz and prochlorperazine both decrease QTc interval. Use Caution/Monitor.

• progesterone intravaginal gel

  Monitor Closely (1)efavirenz will decrease the level or effect of progesterone intravaginal gel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• progesterone micronized

  Monitor Closely (1)efavirenz will decrease the level or effect of progesterone micronized by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• progesterone, natural

  Monitor Closely (1)efavirenz will decrease the level or effect of progesterone, natural by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• proguanil

  Monitor Closely (1)efavirenz decreases levels of proguanil by unspecified interaction mechanism. Use Caution/Monitor. May decrease serum concentrations of the active metabolite of proguanil.

• promethazine

  Monitor Closely (1)efavirenz and promethazine both decrease QTc interval. Use Caution/Monitor.

• propafenone

  Serious - Use Alternative (1)efavirenz and propafenone both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)efavirenz will decrease the level or effect of propafenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• protriptyline

  Monitor Closely (1)efavirenz and protriptyline both increase QTc interval. Use Caution/Monitor.

• quazepam

  Monitor Closely (2)quazepam will increase the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of quazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• quetiapine

  Monitor Closely (1)efavirenz will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.

• quinidine

  Monitor Closely (1)efavirenz will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and quinidine both increase QTc interval. Avoid or Use Alternate Drug.

• quinine

  Serious - Use Alternative (1)efavirenz and quinine both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)efavirenz will decrease the level or effect of quinine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• quinupristin/dalfopristin

  Minor (1)quinupristin/dalfopristin will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• rabeprazole

  Minor (2)efavirenz will increase the level or effect of rabeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
  
  efavirenz will decrease the level or effect of rabeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ramelteon

  Monitor Closely (1)efavirenz will increase the level or effect of ramelteon by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.Minor (1)efavirenz will decrease the level or effect of ramelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ranolazine

  Contraindicated (1)efavirenz and ranolazine both increase QTc interval. Contraindicated.Serious - Use Alternative (1)efavirenz will decrease the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• regorafenib

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of regorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inducers decrease regorafenib levels and increase exposure of the active metabolite M-5

• repaglinide

  Monitor Closely (1)efavirenz will decrease the level or effect of repaglinide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ribociclib

  Monitor Closely (1)efavirenz will decrease the level or effect of ribociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of ribociclib with strong CYP3A inducers should be avoided.Serious - Use Alternative (2)ribociclib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and ribociclib both increase QTc interval. Avoid or Use Alternate Drug.

• rifabutin

  Monitor Closely (1)rifabutin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz will decrease the level or effect of rifabutin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• rifampin

  Monitor Closely (2)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.

• rifapentine

  Minor (1)rifapentine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• rilpivirine

  Contraindicated (1)efavirenz decreases levels of rilpivirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindicated. Rilpivirine should not be used in combination with NNRTIs.Serious - Use Alternative (1)efavirenz and rilpivirine both increase QTc interval. Avoid or Use Alternate Drug.

• rimegepant

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• riociguat

  Monitor Closely (1)efavirenz 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

• ripretinib

  Serious - Use Alternative (1)efavirenz 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)efavirenz will decrease the level or effect of risperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and risperidone both increase QTc interval. Avoid or Use Alternate Drug.

• ritonavir

  Monitor Closely (2)efavirenz will decrease the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  ritonavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.Minor (1)ritonavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• rivaroxaban

  Monitor Closely (1)efavirenz will decrease the level or effect of rivaroxaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• roflumilast

  Monitor Closely (1)efavirenz will decrease the level or effect of roflumilast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration not recommended; strong cytochrome P450 enzyme inducers decrease systemic exposure to roflumilast and may reduce the therapeutic effectiveness

• rolapitant

  Serious - Use Alternative (1)efavirenz 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)efavirenz will decrease the level or effect of romidepsin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with strong 3A4 inducers should be avoided if possible.
  
  efavirenz and romidepsin both increase QTc interval. Use Caution/Monitor.

• ropeginterferon alfa 2b

  Serious - Use Alternative (1)ropeginterferon alfa 2b and efavirenz both increase Other (see comment). Avoid or Use Alternate Drug. Narcotics, hypnotics or sedatives can produce additive neuropsychiatric side effects. Avoid use and monitor patients receiving the combination for effects of excessive CNS toxicity.

• rucaparib

  Monitor Closely (1)rucaparib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.

• rufinamide

  Minor (1)rufinamide will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ruxolitinib

  Monitor Closely (1)efavirenz will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ruxolitinib topical

  Monitor Closely (1)efavirenz will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• salmeterol

  Monitor Closely (1)efavirenz and salmeterol both increase QTc interval. Use Caution/Monitor.

• saquinavir

  Monitor Closely (2)efavirenz will decrease the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  saquinavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.Serious - Use Alternative (2)saquinavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and saquinavir both increase QTc interval. Avoid or Use Alternate Drug.

• saxagliptin

  Minor (1)efavirenz will decrease the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• secobarbital

  Minor (1)secobarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• selexipag

  Monitor Closely (1)efavirenz will increase the level or effect of selexipag by decreasing metabolism. Modify Therapy/Monitor Closely. Reduce selexipag dose to once daily if coadministered with moderate CYP2C8 inhibitors.

• selpercatinib

  Serious - Use Alternative (2)efavirenz will decrease the level or effect of selpercatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and selpercatinib both increase QTc interval. Avoid or Use Alternate Drug.

• selumetinib

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sertraline

  Monitor Closely (2)efavirenz and sertraline both increase QTc interval. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of sertraline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• sevoflurane

  Serious - Use Alternative (1)efavirenz and sevoflurane both increase QTc interval. Avoid or Use Alternate Drug.

• sildenafil

  Monitor Closely (1)efavirenz 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

• silodosin

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of silodosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• simvastatin

  Monitor Closely (1)efavirenz will decrease the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• siponimod

  Serious - Use Alternative (3)efavirenz will increase the level or effect of siponimod by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with drugs that cause moderate CYP2C9 AND a moderate or strong CYP3A4 inhibition is not recommended. Caution if siponimod coadministered with moderate CYP2C9 inhibitors alone.
  
  efavirenz 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.
  
  efavirenz and siponimod both increase QTc interval. Avoid or Use Alternate Drug.

• sirolimus

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• sofosbuvir/velpatasvir

  Serious - Use Alternative (1)efavirenz 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 (2)efavirenz will decrease the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and solifenacin both increase QTc interval. Use Caution/Monitor.

• sonidegib

  Serious - Use Alternative (1)efavirenz 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

  Monitor Closely (1)efavirenz decreases levels of sorafenib by increasing metabolism. Use Caution/Monitor.Serious - Use Alternative (2)efavirenz will decrease the level or effect of sorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and sorafenib both increase QTc interval. Avoid or Use Alternate Drug.

• sotalol

  Serious - Use Alternative (1)efavirenz and sotalol both increase QTc interval. Avoid or Use Alternate Drug.

• sotorasib

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of sotorasib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sparsentan

  Monitor Closely (1)sparsentan will decrease the level or effect of efavirenz 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

  Serious - Use Alternative (1)St John's Wort will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• stavudine

  Monitor Closely (1)efavirenz and stavudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• stiripentol

  Monitor Closely (3)stiripentol, efavirenz. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence.
  
  stiripentol, efavirenz. 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, efavirenz. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.Serious - Use Alternative (1)efavirenz 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.

• sufentanil

  Minor (1)efavirenz will decrease the level or effect of sufentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• sufentanil SL

  Monitor Closely (1)efavirenz 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.

• sulfamethoxazole

  Monitor Closely (1)efavirenz will increase the level or effect of sulfamethoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• sunitinib

  Monitor Closely (1)efavirenz will decrease the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and sunitinib both increase QTc interval. Avoid or Use Alternate Drug.

• suvorexant

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inducers may decrease suvorexant efficacy; if increased suvorexant dose required, do not exceed 20 mg/day

• tacrolimus

  Monitor Closely (1)efavirenz and tacrolimus both increase QTc interval. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz will decrease the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tadalafil

  Monitor Closely (1)efavirenz 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.

• tamoxifen

  Monitor Closely (2)efavirenz, tamoxifen. affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. CYP2C9/10 inhibition decreases tamoxifen metabolism to active metabolites.
  
  efavirenz, tamoxifen. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibition decreases metabolism of tamoxifen to N-desmethyl tamoxifen (active metabolite with similar biologic activity).

• tamsulosin

  Monitor Closely (1)efavirenz increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.

• tasimelteon

  Monitor Closely (1)efavirenz 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

• tazemetostat

  Monitor Closely (1)tazemetostat will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz will decrease the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tecovirimat

  Monitor Closely (1)tecovirimat will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

• telavancin

  Monitor Closely (1)efavirenz and telavancin both increase QTc interval. Use Caution/Monitor.

• telotristat ethyl

  Monitor Closely (1)telotristat ethyl will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Consider increasing dosage of interacting drug, if necessary

• temsirolimus

  Monitor Closely (1)efavirenz will decrease the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• teniposide

  Monitor Closely (1)efavirenz will decrease the level or effect of teniposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tenofovir DF

  Monitor Closely (1)efavirenz and tenofovir DF both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• tepotinib

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of tepotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• terbinafine

  Monitor Closely (1)efavirenz will decrease the level or effect of terbinafine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tetrabenazine

  Serious - Use Alternative (1)efavirenz and tetrabenazine both increase QTc interval. Avoid or Use Alternate Drug.

• tetracycline

  Monitor Closely (1)efavirenz will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tezacaftor

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• theophylline

  Monitor Closely (1)efavirenz will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• thiothixene

  Serious - Use Alternative (1)efavirenz and thiothixene both increase QTc interval. Contraindicated.

• tiagabine

  Monitor Closely (1)efavirenz will decrease the level or effect of tiagabine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ticagrelor

  Monitor Closely (1)efavirenz decreases levels of ticagrelor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid use of ticagrelor with potent CYP3A inducers.

• ticlopidine

  Monitor Closely (2)efavirenz will decrease the level or effect of ticlopidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  ticlopidine will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.

• tinidazole

  Monitor Closely (1)efavirenz will decrease the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tipranavir

  Monitor Closely (3)efavirenz will decrease the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tipranavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
  
  tipranavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tivozanib

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of tivozanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tofacitinib

  Monitor Closely (1)efavirenz increases levels 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.

• tolbutamide

  Monitor Closely (1)efavirenz will increase the level or effect of tolbutamide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.

• tolterodine

  Monitor Closely (1)efavirenz will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tolvaptan

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• topiramate

  Minor (1)topiramate will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• toremifene

  Monitor Closely (1)efavirenz 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.Serious - Use Alternative (1)efavirenz and toremifene both increase QTc interval. Avoid or Use Alternate Drug.

• trabectedin

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tramadol

  Monitor Closely (1)efavirenz will decrease the level or effect of tramadol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• trazodone

  Monitor Closely (1)efavirenz will decrease the level or effect of trazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz and trazodone both increase QTc interval. Avoid or Use Alternate Drug.

• triamcinolone acetonide injectable suspension

  Monitor Closely (1)efavirenz will decrease the level or effect of triamcinolone acetonide injectable suspension by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• triazolam

  Monitor Closely (1)efavirenz will decrease the level or effect of triazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)efavirenz increases levels of triazolam by decreasing metabolism. Contraindicated.

• triclabendazole

  Monitor Closely (1)efavirenz and triclabendazole both increase QTc interval. Use Caution/Monitor.

• trifluoperazine

  Monitor Closely (1)efavirenz and trifluoperazine both decrease QTc interval. Use Caution/Monitor.

• trimipramine

  Monitor Closely (3)efavirenz will decrease the level or effect of trimipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz will decrease the level or effect of trimipramine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
  
  efavirenz and trimipramine both increase QTc interval. Use Caution/Monitor.

• triptorelin

  Monitor Closely (1)efavirenz and triptorelin both increase QTc interval. Use Caution/Monitor.

• tucatinib

  Serious - Use Alternative (3)efavirenz will decrease the level or effect of tucatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz will increase 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 inhibitors increases tucatinib plasma concentrations and risk of toxicities.
  
  tucatinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.

• ublituximab

  Monitor Closely (1)ublituximab decreases effects of efavirenz by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely.

• ubrogepant

  Serious - Use Alternative (1)efavirenz 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)efavirenz 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 (2)efavirenz will decrease the level or effect of umeclidinium bromide/vilanterol inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and umeclidinium bromide/vilanterol inhaled both decrease QTc interval. Use Caution/Monitor.

• upadacitinib

  Serious - Use Alternative (1)efavirenz 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)valbenazine and efavirenz both increase QTc interval. Use Caution/Monitor.

• vandetanib

  Serious - Use Alternative (2)efavirenz decreases levels of vandetanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration with potent CYP3A4 inducers; these drugs reduce exposure to vandetanib by up to 40%.
  
  efavirenz and vandetanib both increase QTc interval. Avoid or Use Alternate Drug.

• vardenafil

  Monitor Closely (2)efavirenz will decrease the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and vardenafil both increase QTc interval. Use Caution/Monitor.

• velpatasvir

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of velpatasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• vemurafenib

  Serious - Use Alternative (2)efavirenz will decrease the level or effect of vemurafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and vemurafenib both increase QTc interval. Avoid or Use Alternate Drug.

• venetoclax

  Serious - Use Alternative (1)efavirenz 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 (2)efavirenz will decrease the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  efavirenz and venlafaxine both decrease QTc interval. Use Caution/Monitor.

• verapamil

  Monitor Closely (1)efavirenz will decrease the level or effect of verapamil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Minor (1)verapamil will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• vilanterol/fluticasone furoate inhaled

  Monitor Closely (2)efavirenz will decrease the level or effect of vilanterol/fluticasone furoate inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid or Use Alternate Drug.
  
  efavirenz and vilanterol/fluticasone furoate inhaled both increase QTc interval. Use Caution/Monitor.

• vilazodone

  Monitor Closely (1)efavirenz 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

  Minor (1)efavirenz will decrease the level or effect of vinblastine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• vincristine

  Minor (1)efavirenz will decrease the level or effect of vincristine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• vincristine liposomal

  Minor (1)efavirenz will decrease the level or effect of vincristine liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• vinorelbine

  Minor (1)efavirenz will decrease the level or effect of vinorelbine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• voclosporin

  Serious - Use Alternative (2)efavirenz will decrease the level or effect of voclosporin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  efavirenz and voclosporin both increase QTc interval. Avoid or Use Alternate Drug.

• vonoprazan

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of vonoprazan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• vorapaxar

  Monitor Closely (1)efavirenz decreases levels of vorapaxar by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• voriconazole

  Contraindicated (2)voriconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindication applies to efavirenz doses of 400 mg/day or higher. This dose of efavirenz induces CYP3A4 resulting in decreased voriconazole levels. When voriconazole is coadministered with efavirenz, voriconazole oral maintenance dose should be increased to 400 mg q12hr and efavirenz should be decreased to 300 mg q24hr.
  
  efavirenz decreases effects of voriconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Contraindication applies to efavirenz doses of 400 mg/day or higher. This dose of efavirenz induces CYP3A4 resulting in decreased voriconazole levels. When voriconazole is coadministered with efavirenz, voriconazole oral maintenance dose should be increased to 400 mg q12hr and efavirenz should be decreased to 300 mg q24hr.Serious - Use Alternative (1)efavirenz and voriconazole both increase QTc interval. Avoid or Use Alternate Drug.

• vorinostat

  Monitor Closely (1)efavirenz and vorinostat both increase QTc interval. Use Caution/Monitor.

• vortioxetine

  Monitor Closely (1)efavirenz 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.

• voxelotor

  Serious - Use Alternative (2)efavirenz 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).
  
  voxelotor will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Voxelotor increases systemic exposure of sensitive CYP3A4 substrates. Avoid coadministration with sensitive CYP3A4 substrates with a narrow therapeutic index. Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid.

• voxilaprevir

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of voxilaprevir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• warfarin

  Monitor Closely (1)efavirenz will decrease 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 inducers of these isoenzymes and adjust warfarin dose if needed.

• zafirlukast

  Minor (1)zafirlukast will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zaleplon

  Minor (1)efavirenz will decrease the level or effect of zaleplon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zanubrutinib

  Serious - Use Alternative (1)efavirenz will decrease the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of zanubrutinib (a CYP3A4 substrate) with moderate CYP3A4 inhibitors. If unavoidable, increase zanubrutinib dose to 320 mg PO BID. After discontinuing the CYP3A4 inhibitor, resume previous dose of zanubrutinib.

• zidovudine

  Monitor Closely (1)efavirenz and zidovudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• ziprasidone

  Serious - Use Alternative (1)efavirenz and ziprasidone both increase QTc interval. Avoid or Use Alternate Drug.Minor (1)efavirenz will decrease the level or effect of ziprasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zolpidem

  Minor (1)efavirenz will decrease the level or effect of zolpidem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• zonisamide

  Monitor Closely (1)efavirenz will decrease the level or effect of zonisamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.