nelfinavir (Rx)

HIV Infection

750 mg PO q8hr, OR

1250 mg PO q12hr

Dosage Modifications

Renal impairment: Dose adjustment not necessary

Hepatic impairment

• Mild impairment (Child-Pugh class A): Dose adjustment not necessary
• Severe impairment (Child-Pugh Class B or C): Not recommended

Multiple Myeloma (Orphan)

Orphan designation for treatment of multiple myeloma

Sponsor

• Swiss Group for Clinical Cancer Research (SAKK); Effingerstrasse 33; Bern, Switzerland

HIV Infection

<2 years: Safety and efficacy not established

2-13 years: 45-55 mg/kg PO q12hr, OR 25-35 mg/kg PO q8hr  

Not to exceed adult dose of 2,500 mg/day (q12hr dosing) or 1,875 mg/day (q8hr dosing)

Adolescents: 1,250 mg PO q12hr, OR 750 mg PO q8hr

Also see Administration

Contraindicated (41)

• alfuzosin

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

• amiodarone

  amiodarone will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Contraindicated.

• cobimetinib

  nelfinavir will increase the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid coadministration with strong CYP3A4 inhibitors with (increases cobimetinib systemic exposure by 6.7-fold).

• conivaptan

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

• dexlansoprazole

  dexlansoprazole decreases levels of nelfinavir by unspecified interaction mechanism. Contraindicated. Coadministration may lead to loss of nelfinavir virologic response and development of resistance; mechanism may be CYP2C19 inhibition of nelfinavir conversion to active M8 metabolite, and also PPIs decreasing gastric pH resulting in decreased nelfinavir absorption.

• dihydroergotamine

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

• dihydroergotamine intranasal

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

• eliglustat

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

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  nelfinavir, 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.

• enzalutamide

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

• ergonovine

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

• esomeprazole

  esomeprazole decreases levels of nelfinavir by unspecified interaction mechanism. Contraindicated. Coadministration may lead to loss of nelfinavir virologic response and development of resistance; mechanism may be CYP2C19 inhibition of nelfinavir conversion to active M8 metabolite, and also PPIs decreasing gastric pH resulting in decreased nelfinavir absorption.

• etravirine

  etravirine increases levels of nelfinavir by decreasing metabolism. Contraindicated.

• finerenone

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

• flibanserin

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

• isavuconazonium sulfate

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

• ivabradine

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

• lansoprazole

  lansoprazole decreases levels of nelfinavir by unspecified interaction mechanism. Contraindicated. Coadministration may lead to loss of nelfinavir virologic response and development of resistance; mechanism may be CYP2C19 inhibition of nelfinavir conversion to active M8 metabolite, and also PPIs decreasing gastric pH resulting in decreased nelfinavir absorption.

• lomitapide

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

• lonafarnib

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

• lovastatin

  nelfinavir will increase the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors increase systemic statin exposure and risk of myopathy, including rhabdomyolysis
  
  lovastatin will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Contraindicated.

• lurasidone

  nelfinavir increases levels of lurasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of lurasidone and strong CYP3A4 inhibitors is contraindicated.

• mavacamten

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

• methylergonovine

  nelfinavir increases levels of methylergonovine by decreasing metabolism. Contraindicated. Potential for serious and/or life threatening reactions (eg, ergot toxicity characterized by peripheral vasospasm, and ischemia of the extremities and other tissues).
  
  nelfinavir will increase the level or effect of methylergonovine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• midazolam

  nelfinavir increases levels of midazolam by decreasing metabolism. Contraindicated. Potential for serious and/or life threatening reactions (eg, prolonged or increased sedation, or respiratory depression).

• naloxegol

  nelfinavir will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of naloxegol with strong CYP3A4 inhibitors can significantly increase naloxegol systemic exposure which may precipitate opioid withdrawal symptoms

• omeprazole

  omeprazole decreases levels of nelfinavir by unspecified interaction mechanism. Contraindicated. Coadministration may lead to loss of nelfinavir virologic response and development of resistance; mechanism may be CYP2C19 inhibition of nelfinavir conversion to active M8 metabolite, and also PPIs decreasing gastric pH resulting in decreased nelfinavir absorption.

• pacritinib

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

• pantoprazole

  pantoprazole decreases levels of nelfinavir by unspecified interaction mechanism. Contraindicated. Coadministration may lead to loss of nelfinavir virologic response and development of resistance; mechanism may be CYP2C19 inhibition of nelfinavir conversion to active M8 metabolite, and also PPIs decreasing gastric pH resulting in decreased nelfinavir absorption.

• pimozide

  nelfinavir increases levels of pimozide by decreasing metabolism. Contraindicated. Potential for serious and/or life-threatening reactions (eg, cardiac arrhythmias).

• rabeprazole

  rabeprazole decreases levels of nelfinavir by unspecified interaction mechanism. Contraindicated. Coadministration may lead to loss of nelfinavir virologic response and development of resistance; mechanism may be CYP2C19 inhibition of nelfinavir conversion to active M8 metabolite, and also PPIs decreasing gastric pH resulting in decreased nelfinavir absorption.

• regorafenib

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

• rifampin

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

• salmeterol

  nelfinavir increases levels of salmeterol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Potential for increased toxicity. .

• sildenafil

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

• simvastatin

  nelfinavir will increase the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  simvastatin will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Contraindicated.
  
  nelfinavir increases toxicity of simvastatin by Other (see comment). Contraindicated. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• St John's Wort

  St John's Wort will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• tipranavir

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

• triazolam

  nelfinavir increases levels of triazolam by decreasing metabolism. Contraindicated. Potential for serious and/or life threatening reactions (eg, prolonged or increased sedation, or respiratory depression).

• venetoclax

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

• voclosporin

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

Serious - Use Alternative (142)

• abametapir

  abametapir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.

• acalabrutinib

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

• adagrasib

  nelfinavir will increase the level or effect of adagrasib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of adagrasib, a CYP3A4 substrate, with strong CYP3A4 inhibitors until adagrasib concentrations have reached steady-state (after ~8 days). If steady state is not reached, concomitant use of strong CYP3A4 inhibitors will increase adagrasib concentrations and risk of its toxicities

• ado-trastuzumab emtansine

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

• afatinib

  nelfinavir increases levels of afatinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Reduce afatinib daily dose by 10 mg if not tolerated when coadministered with P-gp inhibitors.

• amiodarone

  nelfinavir will increase the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  nelfinavir increases levels of amiodarone by decreasing metabolism. Contraindicated.

• apalutamide

  apalutamide will decrease the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP2C19 inducer, with drugs that are CYP2C19 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.
  
  apalutamide will decrease the level or effect of nelfinavir 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.

• apixaban

  nelfinavir will increase the level or effect of apixaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If taking apixaban dose >2.5 mg BID, decrease dose by 50% if coadministered with strong dual inhibitors of CYP3A4 and P-gp; if currently taking apixaban 2.5 mg PO BID, avoid coadministration with strong dual inhibitors of CYP3A4 and P-gp

• atorvastatin

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

• avanafil

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

• avapritinib

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

• axitinib

  nelfinavir increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with strong CYP3A4 inhibitors, reduce axitinib dose by 50%.

• bedaquiline

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

• betibeglogene autotemcel

  nelfinavir, 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.

• bosentan

  bosentan will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. stop bosentan >36 hours prior to PI initiation and restart 10 days after PI initiation at 62.5 mg once daily or every other day.

• bosutinib

  nelfinavir increases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors increases bosutinib plasma concentration ~5-fold.
  
  nelfinavir increases levels of bosutinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• brexpiprazole

  nelfinavir will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Administer half of the usual brexpiprazole dose when coadministered with strong CYP3A4 inhibitors. If also administered with a strong/moderate CYP2D6 inhibitor, administer a quarter of brexpiprazole dose.

• brigatinib

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

• bromocriptine

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

• buprenorphine transdermal

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

• cabergoline

  nelfinavir increases levels of cabergoline by decreasing metabolism. Contraindicated.

• cabotegravir

  nelfinavir, 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

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

• calcitriol

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

• carbamazepine

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

• ceritinib

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

• cimetidine

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

• clarithromycin

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

• colchicine

  nelfinavir will increase the level or effect of colchicine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid use of colchicine with strong CYP3A4 inhibitors. If coadministration is necessary, decrease colchicine dose or frequency as recommended in prescribing information. Use of any colchicine product in conjunction with strong CYP3A4 inhibitors is contraindicated in patients with renal or hepatic impairment.

• copanlisib

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

• cyclosporine

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

• dabrafenib

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

• daridorexant

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

• dronabinol

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

• dronedarone

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

• edoxaban

  nelfinavir will increase the level or effect of edoxaban by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Dose adjustment may be required with strong P-gp inhibitors. DVT/PE treatment: Decrease dose to 30 mg PO once daily. NVAF: No dose reduction recommended

• elbasvir/grazoprevir

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

• eletriptan

  nelfinavir increases levels of eletriptan by decreasing metabolism. Contraindicated. Separate by 72 hours.

• elivaldogene autotemcel

  elivaldogene autotemcel, nelfinavir. 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.

• eluxadoline

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

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

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

• encorafenib

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

• entrectinib

  nelfinavir will increase the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of strong CYP3A4 inhibitors with entrectinib, a CYP3A4 substrate. If coadministration unavoidable, reduce entrectinib dose to 100 mg/day for patients aged 12 y or older with BSA >1.50m2. Resume previous entrectinib dose after discontinuing strong CYP3A inhibitor for 3-5 elimination half-lives.

• enzalutamide

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

• erdafitinib

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

• ergotamine

  nelfinavir will increase the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  nelfinavir increases levels of ergotamine by decreasing metabolism. Contraindicated.

• erythromycin base

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

• erythromycin ethylsuccinate

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

• erythromycin lactobionate

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

• erythromycin stearate

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

• ethinylestradiol

  nelfinavir, ethinylestradiol. Other (see comment). Avoid or Use Alternate Drug. Comment: Significant changes (increase or decrease) can occur in estrogen plasma levels. Efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended. .
  
  nelfinavir will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• everolimus

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

• fedratinib

  nelfinavir will increase the level or effect of fedratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid fedratinib coadministration with strong CYP3A4 inhibitors, decrease fedratinib dose to 200 mg/day. If CYP3A4 inhibitor discontinued, increase fedratinib dose to 300 mg/day for 2 weeks, and then 400 mg/day thereafter as tolerated.
  
  nelfinavir will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.

• felbamate

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

• fentanyl

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

• fentanyl intranasal

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

• fentanyl transdermal

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

• fentanyl transmucosal

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

• fexinidazole

  nelfinavir will decrease the level or effect of fexinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration, monitor fexinidazole for decreased efficacy owing to decreased plasma concentrations of active M1 and M2 metabolites.
  
  fexinidazole will increase the level or effect of nelfinavir 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.

• fluticasone intranasal

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

• gilteritinib

  nelfinavir will increase the level or effect of gilteritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternatives to any strong CYP3A4 inhibitor when coadministered with gilteritinib. If such a combination cannot be avoided, closely monitor for gilteritinib-related adverse effects. Interrupt and reduce gilteritinib dosage in patients with serious or life-threatening toxicity.

• glasdegib

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

• ibrutinib

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

• idelalisib

  nelfinavir will increase the level or effect of idelalisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministered with strong CYP3A inhibitors, monitor for signs of idelalisib toxicity; follow recommendations for dosage modifications if adverse reactions occur
  
  idelalisib will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates

• indinavir

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

• infigratinib

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

• irinotecan

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

• irinotecan liposomal

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

• ivosidenib

  nelfinavir will increase the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of strong CYP3A4 inhibitors with ivosidenib or replace with alternate therapies. If coadministration of a strong CYP3A4 inhibitor is unavoidable, reduce ivosidenib dose to 250 mg qDay. If the strong inhibitor is discontinued, increase ivosidenib dose (after at least 5 half-lives of the strong CYP3A4 inhibitor) to the recommended dose of 500 mg qDay. Monitor for increased risk of QTc interval prolongation.
  
  ivosidenib will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternative therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.

• larotrectinib

  nelfinavir will increase 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 inhibitors is unavoidable, reduce larotrectinib dose by 50%. Resume prior larotrectinib dose once CYP3A4 inhibitor discontinued for 3-5 half-lives.

• lasmiditan

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

• lefamulin

  nelfinavir will increase the level or effect of lefamulin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lefamulin with strong CYP3A inhibitors.

• lemborexant

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

• levonorgestrel intrauterine

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

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  nelfinavir, levonorgestrel oral/ethinylestradiol/ferrous bisglycinate. Other (see comment). Avoid or Use Alternate Drug. Comment: Significant changes (increase or decrease) can occur in estrogen plasma levels. Efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.

• lopinavir

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

• lorlatinib

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

• lurbinectedin

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

• macitentan

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

• medroxyprogesterone

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

• mefloquine

  nelfinavir increases levels of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Potential for increased toxicity. Avoid coadministration during and for 15 weeks after discontinuing mefloquine. .

• midazolam intranasal

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

• midostaurin

  nelfinavir will increase the level or effect of midostaurin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong CYP3A4 inhibitors cannot be avoided, monitor midostaurin for increased risk of adverse reactions, especially during the first week of treatment.

• mobocertinib

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

• neratinib

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

• olaparib

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

• osimertinib

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

• oxycodone

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

• palbociclib

  nelfinavir will increase the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of palbociclib with strong CYP3A inhibitors. If unable to avoid, reduce palbociclib dose to 75 mg/day.

• pazopanib

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

• pemigatinib

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

• pexidartinib

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

• pimavanserin

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

• pomalidomide

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

• ponatinib

  nelfinavir increases levels of ponatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease ponatinib starting dose to 30 mg qDay if coadministration with strong CYP3A4 inhibitors cannot be avoided.

• pralsetinib

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

• progesterone intravaginal gel

  nelfinavir will increase the level or effect of progesterone intravaginal gel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• progesterone micronized

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

• progesterone, natural

  nelfinavir will increase the level or effect of progesterone, natural by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• quazepam

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

• quinidine

  quinidine will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.
  
  nelfinavir increases levels of quinidine by decreasing metabolism. Contraindicated.

• ranolazine

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

• red yeast rice

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

• ribociclib

  nelfinavir will increase the level or effect of ribociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If a strong CYP3A inhibitor must be coadministered with ribociclib, reduce the ribociclib starting dose to 400 mg/day.

• rifabutin

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

• rifapentine

  rifapentine decreases levels of nelfinavir by increasing metabolism. Contraindicated.

• rimegepant

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

• riociguat

  nelfinavir will increase the level or effect of riociguat by decreasing metabolism. Avoid or Use Alternate Drug. Coadministration of riociguat (substrate of CYP isoenzymes 1A1, 2C8, 3A, 2J2) with strong CYP inhibitors may require a decreased initial dose of 0.5 mg PO TID; monitor for signs of hypotension and reduce dose if needed
  
  nelfinavir will increase the level or effect of riociguat by Other (see comment). Avoid or Use Alternate Drug. Coadministration of riociguat (an ABCG2 [BCRP] substrate) with strong ABCG2 inhibitors may require a decreased initial dose of 0.5 mg PO TID; monitor for signs of hypotension and reduce dose if needed
  
  nelfinavir will increase the level or effect of riociguat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• romidepsin

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

• rosuvastatin

  nelfinavir increases toxicity of rosuvastatin by Other (see comment). Avoid or Use Alternate Drug.

• ruxolitinib

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

• ruxolitinib topical

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

• saquinavir

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

• selpercatinib

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

• selumetinib

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

• silodosin

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

• siponimod

  nelfinavir will increase the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a moderate or strong CYP3A4 inhibitor PLUS a moderate or strong CYP2C9 inhibitor is not recommended.

• sirolimus

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

• sonidegib

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

• sotorasib

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

• St John's Wort

  St John's Wort decreases levels of nelfinavir by increasing metabolism. Contraindicated.

• stiripentol

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

• suvorexant

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

• tadalafil

  nelfinavir will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Stop tadalafil >24 hours prior to protease inhibitor (PI) initiation, restart 7 days after PI initiation at 20 mg once daily, and increase to 40 mg once daily based on tolerability.

• tamoxifen

  nelfinavir, tamoxifen. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP3A4 inhibition decreases metabolism of tamoxifen to N-desmethyl tamoxifen (active metabolite with similar biologic activity).

• tamsulosin

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

• tazemetostat

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

• tepotinib

  nelfinavir will increase the level or effect of tepotinib by Other (see comment). Avoid or Use Alternate Drug. Interaction not studied clinically. Metabolism and data suggest drugs that are strong CYP3A4 and P-gp inhibitors may increase tepotinib (a P-gp and CYP3A4 substrate) effects and risk of toxicities.
  
  tepotinib will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If concomitant use unavoidable, reduce the P-gp substrate dosage if recommended in its approved product labeling.

• tiagabine

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

• tofacitinib

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

• tolvaptan

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

• topotecan

  nelfinavir will increase the level or effect of topotecan by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Product labeling for PO topotecan recommends avoiding concomitant use of P-gp inhibitors; the interaction with IV topotecan may be less severe but is still likely of clinical significance

• trabectedin

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

• tucatinib

  tucatinib will increase the level or effect of nelfinavir 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

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

• vemurafenib

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

• venetoclax

  nelfinavir will increase the level or effect of venetoclax by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If a P-gp inhibitor must be used, reduce the venetoclax dose by at least 50%. Monitor more closely for signs of venetoclax toxicities.

• vilazodone

  nelfinavir increases levels of vilazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If intolerable adverse effects occur when coadministered with moderate CYP3A4 inhibitors, reduce daily dose to 20 mg.

• vonoprazan

  vonoprazan will decrease the level or effect of nelfinavir by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• vorapaxar

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

• voriconazole

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

• voxelotor

  voxelotor will increase the level or effect of nelfinavir 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.

Monitor Closely (320)

• abacavir

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

• abemaciclib

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

• acarbose

  nelfinavir decreases effects of acarbose by pharmacodynamic antagonism. Use Caution/Monitor. New onset or exacerbation of diabetes mellitus and hyperglycemia have been reported with protease inhibitors.

• albiglutide

  nelfinavir decreases effects of albiglutide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• almotriptan

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

• alprazolam

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

• amitriptyline

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

• amobarbital

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

• apalutamide

  nelfinavir will increase the level or effect of apalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of apalutamide with strong CYP3A4 or CYP2C8 inhibitors does not require initial dosage modification; however, dose reduction may be needed based on tolerability.

• aprepitant

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

• aripiprazole

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

• armodafinil

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

• artemether/lumefantrine

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

• atazanavir

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

• atogepant

  nelfinavir will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Recommended atogepant dosage is 10 mg PO qDay when coadministered with strong CYP3A4 inhibitors.

• atorvastatin

  nelfinavir will increase the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Limit atorvastatin dose to 40 mg/day
  
  atorvastatin will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• bazedoxifene/conjugated estrogens

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

• benzhydrocodone/acetaminophen

  nelfinavir will increase the level or effect of benzhydrocodone/acetaminophen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with strong CYP3A4 inhibitors may increase hydrocodone (benzhydrocodone is prodrug of hydrocodone) plasma concentrations and can result in potentially fatal respiratory depression.

• berotralstat

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

• betrixaban

  nelfinavir increases levels of betrixaban by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Decrease betrixaban dose to 80 mg PO once, then 40 mg PO qDay if coadministered with a P-gp inhibitor.

• bexarotene

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

• bortezomib

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

• bosutinib

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

• brentuximab vedotin

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

• bromocriptine

  nelfinavir increases levels of bromocriptine by decreasing metabolism. Use Caution/Monitor. Increased levels possibly due to CYP3A4 inhibition.

• budesonide

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

• buprenorphine

  nelfinavir increases levels of buprenorphine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Potential for increased toxicity. .

• buprenorphine buccal

  nelfinavir increases levels of buprenorphine buccal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Potential for increased toxicity. .

• buprenorphine subdermal implant

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

• buprenorphine, long-acting injection

  nelfinavir will increase the level or effect of buprenorphine, long-acting injection by affecting hepatic enzyme CYP2E1 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inhibitors should be monitored to ensure buprenorphine plasma levels are adequate. Within 2 weeks, if signs and symptoms of buprenorphine toxicity or overdose occur and the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.

• bupropion

  nelfinavir, bupropion. decreasing metabolism. Use Caution/Monitor. Incr levels of bupropion, but decr levels of active metabolites. .

• buspirone

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

• butabarbital

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

• butalbital

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

• cabazitaxel

  nelfinavir increases levels of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Potential for increased toxicity. Avoid coadministration.

• calcifediol

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

• cannabidiol

  nelfinavir will increase the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a strong CYP3A4 inhibitor.
  
  cannabidiol will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the dose of sensitive CYP2C19 substrates, as clinically appropriate, when coadministered with cannabidiol.

• capmatinib

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

• carbamazepine

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

• cariprazine

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

• cenobamate

  cenobamate will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.
  
  cenobamate will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider a dose reduction of CYP2C19 substrates, as clinically appropriate, when used concomitantly with cenobamate.

• ceritinib

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

• chlordiazepoxide

  nelfinavir increases levels of chlordiazepoxide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Potential for increased toxicity. Use alternatives if available. Consider lowering benzodiazepine dose.

• ciclesonide inhaled

  nelfinavir increases levels of ciclesonide inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. Increased risk of Cushing's syndrome or adrenal suppression.

• cilostazol

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

• cimetidine

  cimetidine will increase the level or effect of nelfinavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• cinacalcet

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

• citalopram

  nelfinavir increases levels of citalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• clarithromycin

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

• clomipramine

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

• clonazepam

  nelfinavir increases levels of clonazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Potential for increased toxicity. Use alternatives if available. Consider lowering benzodiazepine dose.

• clopidogrel

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

• clorazepate

  nelfinavir increases levels of clorazepate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Use alternatives if available. Consider lowering benzodiazepine dose.

• clotrimazole

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

• clozapine

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

• cocaine topical

  nelfinavir will increase the level or effect of cocaine topical by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.

• conivaptan

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

• conjugated estrogens

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

• conjugated estrogens, vaginal

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

• cortisone

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

• crizotinib

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

• crofelemer

  crofelemer increases levels of nelfinavir 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

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

• cyclosporine

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

• dabigatran

  nelfinavir will increase the level or effect of dabigatran by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Atrial fibrillation: Avoid coadministering dabigatran with P-gp inhibitors if CrCl <30 mL/min. DVT/PE treatment: Avoid coadministering dabigatran with P-gp inhibitors if CrCl <50 mL/min

• dabrafenib

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

• darifenacin

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

• darolutamide

  nelfinavir will increase the level or effect of darolutamide by Other (see comment). Modify Therapy/Monitor Closely. Darolutamide is a P-gp and CYP3A4 substrate. Closely monitor for increased adverse reactions and modify dose of darolutamide as needed when coadministered with drugs that are both P-gp and strong or moderate CYP3A4 inhibitors.

• darunavir

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

• dasatinib

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

• deferasirox

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

• deflazacort

  nelfinavir will increase the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease deflazacort dose to one-third of the recommended dose if coadministered with moderate or strong CYP3A4 inhibitors.

• desipramine

  nelfinavir will increase the level or effect of desipramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• desvenlafaxine

  nelfinavir increases levels of desvenlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• dexamethasone

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

• DHEA, herbal

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

• diazepam

  nelfinavir increases levels of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Use alternatives if available.

• diazepam intranasal

  nelfinavir will increase the level or effect of diazepam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.

• diazoxide

  nelfinavir increases effects of diazoxide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• dichlorphenamide

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

• dienogest/estradiol valerate

  nelfinavir will increase the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Significant changes (increase or decrease) in plasma levels of estrogen and progestin have been seen when HIV protease inhibitors are administered. Monitor for potential adverse effects such as nausea, irregular uterine bleeding, breast tenderness and headache.

• diltiazem

  diltiazem will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor potential serious and/or life threatening reactions such as cardiac arrhythmias.
  
  nelfinavir will increase the level or effect of diltiazem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dofetilide

  nelfinavir increases levels of dofetilide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Potential for increased toxicity. Use alternatives if available. Increased risk of QT prolongation and cardiac arrhythmias.

• doravirine

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

• doxepin cream

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

• doxorubicin

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

• doxorubicin liposomal

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

• dronabinol

  nelfinavir will increase the level or effect of dronabinol by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor. Dronabinol is a CYP3A4 substrate.

• dronedarone

  dronedarone will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  dronedarone will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Combination of nelfinavir and dronedarone should generally be avoided.

• duvelisib

  nelfinavir will increase the level or effect of duvelisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with a strong CYP3A4 inhibitor increases duvelisib AUC, which may increase the risk of duvelisib toxicities. Reduce duvelisib dose to 15 mg BID when coadministered with a strong CYP3A4 inhibitor.

• efavirenz

  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.

• elagolix

  elagolix will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak CYP2C19 inhibitor. Caution with sensitive CYP2C19 substrates.
  
  elagolix will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of elagolix by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of elagolix 200 mg BID with strong CYP3A inhibitors for >1 month is not recommended. Limit elagolix dose to 150 mg qDay and CYP3A inhibitor duration of use to 6 months if coadministered.
  
  elagolix decreases levels of nelfinavir 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.

• eletriptan

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

• eliglustat

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

• elvitegravir

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

• emtricitabine

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

• encorafenib

  encorafenib, nelfinavir. 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.

• enfortumab vedotin

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

• enfuvirtide

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

• erlotinib

  nelfinavir will increase 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 nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• erythromycin ethylsuccinate

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

• erythromycin lactobionate

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

• erythromycin stearate

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

• escitalopram

  nelfinavir increases levels of escitalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. Increased risk of serotonin syndrome.

• eslicarbazepine acetate

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

• estradiol

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

• estradiol vaginal

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

• estrogens conjugated synthetic

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

• estrogens esterified

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

• estropipate

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

• eszopiclone

  nelfinavir increases levels of eszopiclone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce eszopiclone starting dose to 1 mg/day.

• ethosuximide

  nelfinavir increases levels of ethosuximide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• etonogestrel

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

• etoposide

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

• etravirine

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

• exenatide injectable solution

  nelfinavir decreases effects of exenatide injectable solution by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• exenatide injectable suspension

  nelfinavir decreases effects of exenatide injectable suspension by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors.

• famotidine

  famotidine will decrease the level or effect of nelfinavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• fedratinib

  fedratinib will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.
  
  fedratinib will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2C19 substrates as necessary.

• felodipine

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

• fesoterodine

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

• fexinidazole

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

• fluconazole

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

• fludrocortisone

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

• flunisolide inhaled

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

• flurazepam

  nelfinavir increases levels of flurazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Use alternatives if available. Consider lowering benzodiazepine dose.

• fluticasone furoate

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

• fluticasone inhaled

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

• fluvastatin

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

• fluvoxamine

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

• fosamprenavir

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

• fosphenytoin

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

• fostamatinib

  nelfinavir will increase the level or effect of fostamatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A4 inhibitors may increase exposure to R406 (fostamatinib major active metabolite). Monitor for toxicities that may require fostamatinib dose reduction.
  
  fostamatinib will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Concomitant use of fostamatinib may increase concentrations of P-gp substrates. Monitor for toxicities of the P-gp substrate drug that may require dosage reduction when given concurrently with fostamatinib.

• garlic

  garlic decreases levels of nelfinavir by unknown mechanism. Use Caution/Monitor.

• gefitinib

  nelfinavir increases levels of gefitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of strong CYP3A4 inhibitors may increase risk for gefitinib adverse effects.

• glecaprevir/pibrentasvir

  nelfinavir will increase the level or effect of glecaprevir/pibrentasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of glecaprevir/pibrentasvir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  glecaprevir/pibrentasvir will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• glimepiride

  nelfinavir decreases effects of glimepiride by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• glipizide

  nelfinavir decreases effects of glipizide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• glyburide

  nelfinavir decreases effects of glyburide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• grapefruit

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

• griseofulvin

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

• guanfacine

  nelfinavir will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available.

• haloperidol

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

• hydrocodone

  nelfinavir will increase the level or effect of hydrocodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with CYP3A4 inhibitors may increase hydrocodone plasma concentrations and can result in potentially fatal respiratory depression

• hydrocortisone

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

• hydroxyprogesterone caproate

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

• ibuprofen/famotidine

  ibuprofen/famotidine will decrease the level or effect of nelfinavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• ifosfamide

  nelfinavir will decrease the level or effect of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of CYP3A4 inhibitors may decrease the metabolism of ifosfamide to its active alkylating metabolites and decrease the efficacy of ifosfamide.
  
  nelfinavir will decrease the level or effect of ifosfamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Coadministration of ifosfamide with CYP2B6 inhibitors may decrease metabolism of ifosfamide to its metabolite, potentially reducing ifosfamide therapeutic effects.

• iloperidone

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

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

• indacaterol, inhaled

  nelfinavir increases levels of indacaterol, inhaled by Other (see comment). Use Caution/Monitor. Comment: Data suggests that systemic clearance is influenced by modulation of both P-gp and CYP3A4 activities. No dose adjustment is warranted at the 75 mcg dose.

• indinavir

  indinavir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  indinavir will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  indinavir and nelfinavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• insulin aspart

  nelfinavir decreases effects of insulin aspart by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• insulin degludec

  nelfinavir decreases effects of insulin degludec by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. HIV protease inhibitors may cause new onset diabetes mellitus (DM), exacerbate existing DM, and cause hyperglycemia due to insulin resistance.

• insulin degludec/insulin aspart

  nelfinavir decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. HIV protease inhibitors may cause new onset diabetes mellitus (DM), exacerbate existing DM, and cause hyperglycemia due to insulin resistance.

• insulin detemir

  nelfinavir decreases effects of insulin detemir by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• insulin glargine

  nelfinavir decreases effects of insulin glargine by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• insulin glulisine

  nelfinavir decreases effects of insulin glulisine by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• insulin inhaled

  nelfinavir decreases effects of insulin inhaled by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. HIV protease inhibitors may cause new onset diabetes mellitus (DM), exacerbate existing DM, and cause hyperglycemia due to insulin resistance.

• insulin lispro

  nelfinavir decreases effects of insulin lispro by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• insulin NPH

  nelfinavir decreases effects of insulin NPH by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• insulin regular human

  nelfinavir decreases effects of insulin regular human by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• isoniazid

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

• istradefylline

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

• itraconazole

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

• ivacaftor

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

• ixabepilone

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

• ketamine

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

• ketoconazole

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

• lacosamide

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

• lamivudine

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

• lapatinib

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

• letermovir

  nelfinavir increases levels of letermovir by decreasing metabolism. Use Caution/Monitor. Coadminstration of letermovir, an OATP1B1/3 substrate, with OATP1B1/3 inhibitors may increase letermovir plasma concentrations.
  
  letermovir increases levels of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• levamlodipine

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

• levoketoconazole

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

• levomilnacipran

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

• linagliptin

  nelfinavir decreases effects of linagliptin by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .
  
  nelfinavir will increase the level or effect of linagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• liraglutide

  nelfinavir decreases effects of liraglutide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• lomitapide

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

• lopinavir

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

• loratadine

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

• lumacaftor/ivacaftor

  nelfinavir increases levels of lumacaftor/ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A inhibitors do not impact lumacaftor exposure, but increased ivacaftor exposure by 4.3-fold. Due to the induction effect of lumacaftor on CYP3A, at steady-state the net exposure of ivacaftor is not expected to exceed that when given in the absence of lumacaftor at a dose of 150 mg q12hr (the approved dose of ivacaftor monotherapy). Therefore, no dose adjustment is necessary when CYP3A inhibitors are initiated in patients currently taking lumacaftor/ivacaftor. However, when initiating lumacaftor/ivacaftor in patients taking strong CYP3A inhibitors, reduce the dose to 1 tablet daily (lumacaftor 200 mg/ivacaftor 125 mg total daily dose) for the first week of treatment to allow for the steady-state induction effect of lumacaftor. Following this period, continue with the recommended daily dose. No dose adjustment is required for moderate or weak CYP3A4 inhibitors.
  
  lumacaftor/ivacaftor, nelfinavir. affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2C19 substrates. .

• lumateperone

  nelfinavir will increase the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce lumateperone dose to 10.5 mg/day if coadministered with strong CYP3A4 inhibitors.

• lumefantrine

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

• maraviroc

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

• marijuana

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

• mavacamten

  nelfinavir will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• meperidine

  nelfinavir increases levels of meperidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• mestranol

  nelfinavir will increase the level or effect of mestranol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir decreases levels of mestranol by increasing metabolism. Use Caution/Monitor. May result in contraceptive failure.

• metformin

  nelfinavir decreases effects of metformin by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• methadone

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

• methylprednisolone

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

• metronidazole

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

• miconazole vaginal

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

• midazolam

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

• mifepristone

  nelfinavir, mifepristone. Either increases levels of the other by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Do not exceed mifepristone 300 mg/day for Cushing syndrome when coadministered with strong CYP3A4 inhibitors.
  
  mifepristone will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• miglitol

  nelfinavir decreases effects of miglitol by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• mipomersen

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

• mirtazapine

  nelfinavir increases levels of mirtazapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• mitotane

  mitotane decreases levels of nelfinavir 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

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

• mometasone inhaled

  nelfinavir increases levels of mometasone inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. Increased risk of Cushing's syndrome or adrenal suppression.

• mometasone, intranasal

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

• nafcillin

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

• naldemedine

  nelfinavir increases levels of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with strong or moderate CYP3A4 inhibitors.
  
  nelfinavir increases levels of naldemedine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with P-gp inhibitors.

• nateglinide

  nelfinavir decreases effects of nateglinide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• nefazodone

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

• netupitant/palonosetron

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

• nevirapine

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

• nicardipine

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

• nifedipine

  nelfinavir will increase the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Consider initiating nifedipine at the lowest dose available if given concomitantly with this medication
  
  nifedipine will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nifedipine will decrease the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• nilotinib

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

• nintedanib

  nelfinavir increases levels of nintedanib by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. If nintedanib adverse effects occur, management may require interruption, dose reduction, or discontinuation of therapy .

• nirmatrelvir

  nirmatrelvir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Patients on ritonavir- or cobicistat-containing HIV regimens should continue their treatment as indicated. Monitor for increased nirmatrelvir/ritonavir or protease inhibitor adverse events with concomitant use.

• nirmatrelvir/ritonavir

  nirmatrelvir/ritonavir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Patients on ritonavir- or cobicistat-containing HIV regimens should continue their treatment as indicated. Monitor for increased nirmatrelvir/ritonavir or protease inhibitor adverse events with concomitant use.

• nisoldipine

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

• nizatidine

  nizatidine will decrease the level or effect of nelfinavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• norethindrone

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

• oliceridine

  nelfinavir will increase the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.

• ombitasvir/paritaprevir/ritonavir

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

• ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)

  nelfinavir will increase the level or effect of ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ondansetron

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

• orlistat

  orlistat will decrease the level or effect of nelfinavir 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

  nelfinavir will increase the level or effect of osilodrostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce dose of osilodrostat, a CYP3A4 substrate, by half when coadministered with a strong CYP3A4 inhibitor.

• ospemifene

  nelfinavir increases levels of ospemifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• oxcarbazepine

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

• panobinostat

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

• paricalcitol

  nelfinavir increases levels of paricalcitol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• pentobarbital

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

• perampanel

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

• phenobarbital

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

• phenytoin

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

• pitavastatin

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

• polatuzumab vedotin

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

• ponatinib

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

• posaconazole

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

• pramlintide

  nelfinavir decreases effects of pramlintide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• pravastatin

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

• praziquantel

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

• prednisolone

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

• prednisone

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

• primidone

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

• quercetin

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

• quetiapine

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

• quinidine

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

• quinupristin/dalfopristin

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

• ranolazine

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

• repaglinide

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

• ribociclib

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

• rifapentine

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

• rifaximin

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

• rilpivirine

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

• ripretinib

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

• ritonavir

  nelfinavir will increase the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  ritonavir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  ritonavir will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  nelfinavir and ritonavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• rivaroxaban

  nelfinavir increases levels of rivaroxaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid concomitant use of rivaroxaban and combined Pgp and strong CYP3A4 inhibitors. Combination may lead to significant increases in rivaroxaban levels and increase bleeding risk.

• rosiglitazone

  nelfinavir decreases effects of rosiglitazone by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• rucaparib

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

• rufinamide

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

• sacubitril/valsartan

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

• saquinavir

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

• sarecycline

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

• saxagliptin

  nelfinavir will increase the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Limit saxagliptin dose to 2.5 mg/day when coadministered with strong CYP3A4 inhibitors

• secobarbital

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

• sertraline

  nelfinavir increases levels of sertraline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• sirolimus

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

• sitagliptin

  nelfinavir decreases effects of sitagliptin by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• sodium zirconium cyclosilicate

  sodium zirconium cyclosilicate will decrease the level or effect of nelfinavir by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Check specific recommendations for drugs that exhibit pH-dependent solubility that may affect their systemic exposure and efficacy. In general, administer drugs at least 2 hr before or after sodium zirconium cyclosilicate.

• sofosbuvir/velpatasvir

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

• solifenacin

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

• sorafenib

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

• St John's Wort

  St John's Wort will decrease the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• stavudine

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

• stiripentol

  stiripentol, nelfinavir. 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 will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the dose of CYP2C19 substrates, if adverse reactions are experienced when administered concomitantly with stiripentol.
  
  stiripentol will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing the dose of P-glycoprotein (P-gp) substrates, if adverse reactions are experienced when administered concomitantly with stiripentol.

• sufentanil SL

  nelfinavir will increase the level or effect of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of sufentanil SL with any CYP3A4 inhibitor may increase sufentanil plasma concentration, and, thereby increase or prolonged adverse effects, including potentially fatal respiratory depression.

• sunitinib

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

• tacrolimus

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

• tacrolimus ointment

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

• tasimelteon

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

• tazemetostat

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

• tecovirimat

  tecovirimat will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Tecovirimat is a weak inhibitor of CYP2C8 and CYP2C19. Monitor for adverse effects if coadministered with sensitive substrates of these enzymes.
  
  tecovirimat will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

• temsirolimus

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

• teniposide

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

• tenofovir DF

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

• terbinafine

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

• tezacaftor

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

• theophylline

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

• ticagrelor

  nelfinavir increases levels of ticagrelor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Ticagrelor is metabolized by CYP3A4/5. Avoid use with strong CYP3A inhibitors.

• tinidazole

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

• tipranavir

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

• tisotumab vedotin

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

• tolterodine

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

• tolvaptan

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

• topiramate

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

• toremifene

  nelfinavir increases levels of toremifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Metabolism of toremifene may be inhibited by drugs known to inhibit CYP3A4 hepatic enzymes.

• tramadol

  nelfinavir increases levels of tramadol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• trazodone

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

• triamcinolone acetonide injectable suspension

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

• triazolam

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

• triclabendazole

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

• trimipramine

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

• tucatinib

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

• ublituximab

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

• ulipristal

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

• umeclidinium bromide/vilanterol inhaled

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

• upadacitinib

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

• valbenazine

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

• valsartan

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

• vardenafil

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

• velpatasvir

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

• vemurafenib

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

• verapamil

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

• vilanterol/fluticasone furoate inhaled

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

• voriconazole

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

• voxilaprevir

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

• warfarin

  nelfinavir will increase the level or effect of warfarin by Other (see comment). Use Caution/Monitor. Warfarin's less potent R-enantiomer is metabolized in part by CYP3A4 (and also CYP1A2 and CYP2C19). Monitor INR more frequently if coadministered with inhibitors of these isoenzymes and adjust warfarin dose if needed.

• zafirlukast

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

• zanubrutinib

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

• zidovudine

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

• zileuton

  nelfinavir increases levels of zileuton by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

Minor (55)

• acetazolamide

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

• alfentanil

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

• aliskiren

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

• alosetron

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

• ambrisentan

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

• amlodipine

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

• anastrozole

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

• armodafinil

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

• atazanavir

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

• bosentan

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

• caspofungin

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

• cevimeline

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

• clarithromycin

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

• cyclophosphamide

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

• dapsone

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

• didanosine

  didanosine increases levels of nelfinavir by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• disopyramide

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

• docetaxel

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

• donepezil

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

• dutasteride

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

• efavirenz

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

• eplerenone

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

• eucalyptus

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

• finasteride

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

• galantamine

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

• ganaxolone

  nelfinavir, ganaxolone. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. Changes in ganaxolone exposures when coadministered with strong, moderate, or weak CYP3A4 inhibitors are not expected to be clinically significant.

• imatinib

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

• isradipine

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

• itraconazole

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

• ixazomib

  nelfinavir, ixazomib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. In clinical trials, coadministration of ixazomib with strong CYP3A inhibitors did not result in a clinically meaningful change in the systemic exposure of ixazomib.

• ketoconazole

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

• lansoprazole

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

• levoketoconazole

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

• montelukast

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

• nimodipine

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

• nitrendipine

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

• oxybutynin

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

• paclitaxel

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

• paclitaxel protein bound

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

• parecoxib

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

• pimozide

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

• pioglitazone

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

• propafenone

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

• quinine

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

• rabeprazole

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

• ramelteon

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

• sufentanil

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

• vinblastine

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

• vincristine

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

• vincristine liposomal

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

• vinorelbine

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

• zaleplon

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

• ziprasidone

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

• zolpidem

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

• zonisamide

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

• abacavir

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

• abametapir

  Serious - Use Alternative (1)abametapir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. For 2 weeks after abametapir application, avoid taking drugs that are CYP3A4 substrates. If not feasible, avoid use of abametapir.

• abemaciclib

  Monitor Closely (1)nelfinavir will increase the level or effect of abemaciclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A4 inhibitors increase plasma levels of abemaciclib and its metabolites. Abemaciclib dose reduction required. If a strong CYP3A4 inhibitor is discontinued, increase abemaciclib to the dose prior to initiating the strong inhibitor.

• acalabrutinib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of acalabrutinib with strong CYP3A inhibitors. If a strong CYP3A inhibitor must be used short-term (eg, up to 7 days), temporarily interrupt treatment with acalabrutinib.

• acarbose

  Monitor Closely (1)nelfinavir decreases effects of acarbose by pharmacodynamic antagonism. Use Caution/Monitor. New onset or exacerbation of diabetes mellitus and hyperglycemia have been reported with protease inhibitors.

• acetazolamide

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

• adagrasib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of adagrasib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of adagrasib, a CYP3A4 substrate, with strong CYP3A4 inhibitors until adagrasib concentrations have reached steady-state (after ~8 days). If steady state is not reached, concomitant use of strong CYP3A4 inhibitors will increase adagrasib concentrations and risk of its toxicities

• ado-trastuzumab emtansine

  Serious - Use Alternative (1)nelfinavir increases levels of ado-trastuzumab emtansine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. DM1, the cytotoxic component, is metabolized mainly by CYP3A4; strong CYP3A4 inhibitors may increase DM1 exposure and toxicity.

• afatinib

  Serious - Use Alternative (1)nelfinavir increases levels of afatinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Reduce afatinib daily dose by 10 mg if not tolerated when coadministered with P-gp inhibitors.

• albiglutide

  Monitor Closely (1)nelfinavir decreases effects of albiglutide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• alfentanil

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

• alfuzosin

  Contraindicated (1)nelfinavir will increase the level or effect of alfuzosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• aliskiren

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

• almotriptan

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

• alosetron

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

• alprazolam

  Monitor Closely (1)nelfinavir will increase the level or effect of alprazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ambrisentan

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

• amiodarone

  Contraindicated (1)amiodarone will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Contraindicated.Serious - Use Alternative (2)nelfinavir increases levels of amiodarone by decreasing metabolism. Contraindicated.
  
  nelfinavir will increase the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• amitriptyline

  Monitor Closely (1)nelfinavir will increase the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• amlodipine

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

• amobarbital

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

• anastrozole

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

• apalutamide

  Monitor Closely (1)nelfinavir will increase the level or effect of apalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of apalutamide with strong CYP3A4 or CYP2C8 inhibitors does not require initial dosage modification; however, dose reduction may be needed based on tolerability.Serious - Use Alternative (2)apalutamide will decrease the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP2C19 inducer, with drugs that are CYP2C19 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.
  
  apalutamide will decrease the level or effect of nelfinavir 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.

• apixaban

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of apixaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If taking apixaban dose >2.5 mg BID, decrease dose by 50% if coadministered with strong dual inhibitors of CYP3A4 and P-gp; if currently taking apixaban 2.5 mg PO BID, avoid coadministration with strong dual inhibitors of CYP3A4 and P-gp

• aprepitant

  Monitor Closely (2)aprepitant will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of aprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• aripiprazole

  Monitor Closely (1)nelfinavir will increase the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• armodafinil

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

• artemether/lumefantrine

  Monitor Closely (2)artemether/lumefantrine will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• atazanavir

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

• atogepant

  Monitor Closely (1)nelfinavir will increase the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Recommended atogepant dosage is 10 mg PO qDay when coadministered with strong CYP3A4 inhibitors.

• atorvastatin

  Monitor Closely (2)atorvastatin will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Limit atorvastatin dose to 40 mg/daySerious - Use Alternative (1)nelfinavir increases toxicity of atorvastatin by Other (see comment). Avoid or Use Alternate Drug. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• avanafil

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; significantly increased levels may result in significant adverse events including severe hypotension, syncope, visual changes, and priapism. Coadministration with strong CYP3A4 is contraindicated.

• avapritinib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of avapritinib with strong CYP3A4 inhibitors.

• axitinib

  Serious - Use Alternative (1)nelfinavir increases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with strong CYP3A4 inhibitors, reduce axitinib dose by 50%.

• bazedoxifene/conjugated estrogens

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

• bedaquiline

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of bedaquiline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of bedaquiline with strong CYP3A4 inhibitors for >14 consecutive days, unless the benefit of treatment outweighs the risk

• benzhydrocodone/acetaminophen

  Monitor Closely (1)nelfinavir will increase the level or effect of benzhydrocodone/acetaminophen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with strong CYP3A4 inhibitors may increase hydrocodone (benzhydrocodone is prodrug of hydrocodone) plasma concentrations and can result in potentially fatal respiratory depression.

• berotralstat

  Monitor Closely (1)berotralstat will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor or titrate P-gp substrate dose if coadministered.

• betibeglogene autotemcel

  Serious - Use Alternative (1)nelfinavir, 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.

• betrixaban

  Monitor Closely (1)nelfinavir increases levels of betrixaban by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Decrease betrixaban dose to 80 mg PO once, then 40 mg PO qDay if coadministered with a P-gp inhibitor.

• bexarotene

  Monitor Closely (1)nelfinavir will increase the level or effect of bexarotene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• bortezomib

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

• bosentan

  Serious - Use Alternative (1)bosentan will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. stop bosentan >36 hours prior to PI initiation and restart 10 days after PI initiation at 62.5 mg once daily or every other day.Minor (1)nelfinavir will increase the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• bosutinib

  Monitor Closely (1)bosutinib increases levels of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)nelfinavir increases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors increases bosutinib plasma concentration ~5-fold.
  
  nelfinavir increases levels of bosutinib by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• brentuximab vedotin

  Monitor Closely (1)nelfinavir increases levels of brentuximab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor patients for adverse reactions. .

• brexpiprazole

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Administer half of the usual brexpiprazole dose when coadministered with strong CYP3A4 inhibitors. If also administered with a strong/moderate CYP2D6 inhibitor, administer a quarter of brexpiprazole dose.

• brigatinib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of brigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use of a strong CYP3A inhibitor cannot be avoided, reduce the brigatinib once daily dose by about 50% (ie, from 180 mg to 90 mg, or from 90 mg to 60 mg). After discontinuation of a strong CYP3A inhibitor, resume the brigatinib dose that was tolerated prior to initiating the strong CYP3A inhibitor.

• bromocriptine

  Monitor Closely (1)nelfinavir increases levels of bromocriptine by decreasing metabolism. Use Caution/Monitor. Increased levels possibly due to CYP3A4 inhibition.Serious - Use Alternative (1)nelfinavir will increase the level or effect of bromocriptine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• budesonide

  Monitor Closely (1)nelfinavir will increase the level or effect of budesonide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• buprenorphine

  Monitor Closely (1)nelfinavir increases levels of buprenorphine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Potential for increased toxicity. .

• buprenorphine buccal

  Monitor Closely (1)nelfinavir increases levels of buprenorphine buccal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Potential for increased toxicity. .

• buprenorphine subdermal implant

  Monitor Closely (1)nelfinavir will increase the level or effect of buprenorphine subdermal implant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor patients already on buprenorphine subdermal implant who require newly-initiated treatment with CYP3A4 inhibitors for signs and symptoms of overmedication. If the dose of the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, implant removal may be necessary and the patient should then be treated with a buprenorphine dosage form that permits dose adjustments. If a CYP3A4 inhibitor is discontinued in a patient who has been stabilized on buprenorphine, monitor the patient for withdrawal.

• buprenorphine transdermal

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of buprenorphine transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• buprenorphine, long-acting injection

  Monitor Closely (1)nelfinavir will increase the level or effect of buprenorphine, long-acting injection by affecting hepatic enzyme CYP2E1 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inhibitors should be monitored to ensure buprenorphine plasma levels are adequate. Within 2 weeks, if signs and symptoms of buprenorphine toxicity or overdose occur and the concomitant CYP3A4 inhibitor cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.

• bupropion

  Monitor Closely (1)nelfinavir, bupropion. decreasing metabolism. Use Caution/Monitor. Incr levels of bupropion, but decr levels of active metabolites. .

• buspirone

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

• butabarbital

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

• butalbital

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

• cabazitaxel

  Monitor Closely (1)nelfinavir increases levels of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Potential for increased toxicity. Avoid coadministration.

• cabergoline

  Serious - Use Alternative (1)nelfinavir increases levels of cabergoline by decreasing metabolism. Contraindicated.

• cabotegravir

  Serious - Use Alternative (1)nelfinavir, 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)nelfinavir will increase the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of cabozantinib with strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor is required, decrease cabozantinib dose by 40 mg/day (Cometriq) or by 20 mg/day (Cabometyx). Resume previous dose 2-3 days after strong CYP3A4 inhibitor discontinued.

• calcifediol

  Monitor Closely (1)nelfinavir, calcifediol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. CYP450 inhibitors may inhibit enzymes involved in vitamin D metabolism (CYP24A1 and CYP27B1). This may alter serum levels of calcifediol and decrease the conversion of calcifediol to calcitriol. Dose adjustment of calcifediol may be required, and serum 25­hydroxyvitamin D, intact PTH, and serum calcium concentrations should be closely monitored when initiating or discontinuing a strong CYP3A4 inhibitor.

• calcitriol

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

• cannabidiol

  Monitor Closely (2)nelfinavir will increase the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a strong CYP3A4 inhibitor.
  
  cannabidiol will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the dose of sensitive CYP2C19 substrates, as clinically appropriate, when coadministered with cannabidiol.

• capmatinib

  Monitor Closely (1)nelfinavir will increase the level or effect of capmatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• carbamazepine

  Monitor Closely (1)nelfinavir will increase the level or effect of carbamazepine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor plasma levels when used concomitantlySerious - Use Alternative (1)carbamazepine will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• cariprazine

  Monitor Closely (1)nelfinavir will increase the level or effect of cariprazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with strong CYP3A4 inhibitors requires cariprazine dose reduction. See Dosage Modification section in drug monograph.

• caspofungin

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

• cenobamate

  Monitor Closely (2)cenobamate will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.
  
  cenobamate will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider a dose reduction of CYP2C19 substrates, as clinically appropriate, when used concomitantly with cenobamate.

• ceritinib

  Monitor Closely (1)nelfinavir increases levels of ceritinib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)nelfinavir increases levels of ceritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid if possible; if concomitant use is unavoidable, reduce ceritinib dose by ~33%; after discontinuation of strong CYP3A inhibitor, resume at previous dose.
  
  ceritinib will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• cevimeline

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

• chlordiazepoxide

  Monitor Closely (1)nelfinavir increases levels of chlordiazepoxide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Potential for increased toxicity. Use alternatives if available. Consider lowering benzodiazepine dose.

• ciclesonide inhaled

  Monitor Closely (1)nelfinavir increases levels of ciclesonide inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. Increased risk of Cushing's syndrome or adrenal suppression.

• cilostazol

  Monitor Closely (1)nelfinavir will increase the level or effect of cilostazol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cimetidine

  Monitor Closely (1)cimetidine will increase the level or effect of nelfinavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.Serious - Use Alternative (1)cimetidine will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• cinacalcet

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

• citalopram

  Monitor Closely (1)nelfinavir increases levels of citalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• clarithromycin

  Monitor Closely (1)clarithromycin will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)clarithromycin will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.Minor (1)nelfinavir will increase the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• clomipramine

  Monitor Closely (1)nelfinavir will increase the level or effect of clomipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• clonazepam

  Monitor Closely (1)nelfinavir increases levels of clonazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Potential for increased toxicity. Use alternatives if available. Consider lowering benzodiazepine dose.

• clopidogrel

  Monitor Closely (1)nelfinavir will decrease the level or effect of clopidogrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Inhibition of CYP3A4 will reduce clopidogrel bioactivation

• clorazepate

  Monitor Closely (1)nelfinavir increases levels of clorazepate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Use alternatives if available. Consider lowering benzodiazepine dose.

• clotrimazole

  Monitor Closely (1)clotrimazole will decrease the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• clozapine

  Monitor Closely (1)nelfinavir will increase the level or effect of clozapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• cobimetinib

  Contraindicated (1)nelfinavir will increase the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid coadministration with strong CYP3A4 inhibitors with (increases cobimetinib systemic exposure by 6.7-fold).

• cocaine topical

  Monitor Closely (1)nelfinavir will increase the level or effect of cocaine topical by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.

• colchicine

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of colchicine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid use of colchicine with strong CYP3A4 inhibitors. If coadministration is necessary, decrease colchicine dose or frequency as recommended in prescribing information. Use of any colchicine product in conjunction with strong CYP3A4 inhibitors is contraindicated in patients with renal or hepatic impairment.

• conivaptan

  Contraindicated (1)nelfinavir will increase the level or effect of conivaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of conivaptan with strong CYP3A4 inhibitors is contraindicated.Monitor Closely (1)conivaptan will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• conjugated estrogens

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

• conjugated estrogens, vaginal

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

• copanlisib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of copanlisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use with strong CYP3A inhibitors cannot be avoided, reduce copanlisib dose to 45 mg.

• cortisone

  Monitor Closely (1)nelfinavir will increase the level or effect of cortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• crizotinib

  Monitor Closely (2)nelfinavir increases levels of crizotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Concomitant use of strong CYP3A inhibitors should be avoided. .
  
  crizotinib increases levels of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• crofelemer

  Monitor Closely (1)crofelemer increases levels of nelfinavir 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)nelfinavir will increase 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 nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• cyclosporine

  Monitor Closely (2)cyclosporine will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  cyclosporine will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nelfinavir will increase the level or effect of cyclosporine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dabigatran

  Monitor Closely (1)nelfinavir will increase the level or effect of dabigatran by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Atrial fibrillation: Avoid coadministering dabigatran with P-gp inhibitors if CrCl <30 mL/min. DVT/PE treatment: Avoid coadministering dabigatran with P-gp inhibitors if CrCl <50 mL/min

• dabrafenib

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

• dapsone

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

• daridorexant

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

• darifenacin

  Monitor Closely (2)darifenacin will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of darifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• darolutamide

  Monitor Closely (1)nelfinavir will increase the level or effect of darolutamide by Other (see comment). Modify Therapy/Monitor Closely. Darolutamide is a P-gp and CYP3A4 substrate. Closely monitor for increased adverse reactions and modify dose of darolutamide as needed when coadministered with drugs that are both P-gp and strong or moderate CYP3A4 inhibitors.

• darunavir

  Monitor Closely (3)darunavir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of darunavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  darunavir and nelfinavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• dasatinib

  Monitor Closely (2)dasatinib will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• deferasirox

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

• deflazacort

  Monitor Closely (1)nelfinavir will increase the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Decrease deflazacort dose to one-third of the recommended dose if coadministered with moderate or strong CYP3A4 inhibitors.

• desipramine

  Monitor Closely (1)nelfinavir will increase the level or effect of desipramine by affecting hepatic enzyme CYP2D6 metabolism. Use Caution/Monitor.

• desvenlafaxine

  Monitor Closely (1)nelfinavir increases levels of desvenlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• dexamethasone

  Monitor Closely (1)nelfinavir will increase the level or effect of dexamethasone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• dexlansoprazole

  Contraindicated (1)dexlansoprazole decreases levels of nelfinavir by unspecified interaction mechanism. Contraindicated. Coadministration may lead to loss of nelfinavir virologic response and development of resistance; mechanism may be CYP2C19 inhibition of nelfinavir conversion to active M8 metabolite, and also PPIs decreasing gastric pH resulting in decreased nelfinavir absorption.

• DHEA, herbal

  Monitor Closely (1)DHEA, herbal will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• diazepam

  Monitor Closely (1)nelfinavir increases levels of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Use alternatives if available.

• diazepam intranasal

  Monitor Closely (1)nelfinavir will increase the level or effect of diazepam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam.

• diazoxide

  Monitor Closely (1)nelfinavir increases effects of diazoxide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• dichlorphenamide

  Monitor Closely (1)dichlorphenamide, nelfinavir. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Both drugs can cause metabolic acidosis.

• didanosine

  Minor (1)didanosine increases levels of nelfinavir by enhancing GI absorption. Applies only to oral form of both agents. Minor/Significance Unknown.

• dienogest/estradiol valerate

  Monitor Closely (1)nelfinavir will increase the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Significant changes (increase or decrease) in plasma levels of estrogen and progestin have been seen when HIV protease inhibitors are administered. Monitor for potential adverse effects such as nausea, irregular uterine bleeding, breast tenderness and headache.

• dihydroergotamine

  Contraindicated (1)nelfinavir will increase the level or effect of dihydroergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• dihydroergotamine intranasal

  Contraindicated (1)nelfinavir will increase the level or effect of dihydroergotamine intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• diltiazem

  Monitor Closely (2)diltiazem will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor potential serious and/or life threatening reactions such as cardiac arrhythmias.
  
  nelfinavir will increase the level or effect of diltiazem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• disopyramide

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

• docetaxel

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

• dofetilide

  Monitor Closely (1)nelfinavir increases levels of dofetilide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Potential for increased toxicity. Use alternatives if available. Increased risk of QT prolongation and cardiac arrhythmias.

• donepezil

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

• doravirine

  Monitor Closely (1)nelfinavir will increase the level or effect of doravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of doravirine and CYP3A4 inhibitors may increase plasma concentrations and toxicities of doravirine.

• doxepin cream

  Monitor Closely (1)nelfinavir will increase the level or effect of doxepin cream by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• doxorubicin

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

• doxorubicin liposomal

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

• dronabinol

  Monitor Closely (1)nelfinavir will increase the level or effect of dronabinol by affecting hepatic enzyme CYP2E1 metabolism. Use Caution/Monitor. Dronabinol is a CYP3A4 substrate.Serious - Use Alternative (1)nelfinavir will increase the level or effect of dronabinol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dronedarone

  Monitor Closely (2)dronedarone will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  dronedarone will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Combination of nelfinavir and dronedarone should generally be avoided.Serious - Use Alternative (1)nelfinavir will increase the level or effect of dronedarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• dutasteride

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

• duvelisib

  Monitor Closely (1)nelfinavir will increase the level or effect of duvelisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with a strong CYP3A4 inhibitor increases duvelisib AUC, which may increase the risk of duvelisib toxicities. Reduce duvelisib dose to 15 mg BID when coadministered with a strong CYP3A4 inhibitor.

• edoxaban

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of edoxaban by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Dose adjustment may be required with strong P-gp inhibitors. DVT/PE treatment: Decrease dose to 30 mg PO once daily. NVAF: No dose reduction recommended

• efavirenz

  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.

• elagolix

  Monitor Closely (4)elagolix will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  elagolix will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak CYP2C19 inhibitor. Caution with sensitive CYP2C19 substrates.
  
  nelfinavir will increase the level or effect of elagolix by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of elagolix 200 mg BID with strong CYP3A inhibitors for >1 month is not recommended. Limit elagolix dose to 150 mg qDay and CYP3A inhibitor duration of use to 6 months if coadministered.
  
  elagolix decreases levels of nelfinavir 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

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of elbasvir/grazoprevir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• eletriptan

  Monitor Closely (1)nelfinavir will increase the level or effect of eletriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)nelfinavir increases levels of eletriptan by decreasing metabolism. Contraindicated. Separate by 72 hours.

• eliglustat

  Contraindicated (1)nelfinavir will increase the level or effect of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors are contraindicated with eliglustat poor or intermediate metabolizers; reduce eliglustat dose from 84 mg BID to 84 mg once daily in extensive metabolizers; eliglustat is contraindiated if strong or moderate CYP2D6 inhibitors are given concomitantly with strong or moderate CYP3A inhibitorsMonitor Closely (1)eliglustat increases levels of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Monitor therapeutic drug concentrations, as indicated, or consider reducing the dosage of the P-gp substrate and titrate to clinical effect.

• elivaldogene autotemcel

  Serious - Use Alternative (1)elivaldogene autotemcel, nelfinavir. 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.

• eluxadoline

  Serious - Use Alternative (1)nelfinavir increases levels of eluxadoline by decreasing metabolism. Avoid or Use Alternate Drug. Decrease eluxadoline dose to 75 mg PO BID if coadministered with OATP1B1 inhibitors. .

• elvitegravir

  Monitor Closely (1)nelfinavir increases levels of elvitegravir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Elvitegravir is a CYP3A4 substrate; if coadministered with strong CYP3A4 inhibitors may increase levels.

• elvitegravir/cobicistat/emtricitabine/tenofovir DF

  Contraindicated (1)nelfinavir, 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)nelfinavir will increase 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)nelfinavir and emtricitabine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• encorafenib

  Monitor Closely (1)encorafenib, nelfinavir. 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 (1)nelfinavir will increase the level or effect of encorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If concomitant use of a strong CYP3A4 inhibitor is unavoidable, reduce encorafenib dose to one-third of the dose (eg, reduce from 450 mg/day to 150 mg/day). After discontinuing the inhibitor for 3-5 elimination half-lives, resume previous encorafenib dose.

• enfortumab vedotin

  Monitor Closely (1)nelfinavir will increase the level or effect of enfortumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Enfortumab vedotin is an antibody-drug conjugate that releases monomethylauristatin E (MMAE) via proteolytic cleavage. MMAE is primarily metabolized by CYP3A4 in vitro. Coadministration with strong CYP3A4 inhibitors may increase free MMAE exposure, which may increase the incidence or severity of toxicities.

• enfuvirtide

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

• entrectinib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of strong CYP3A4 inhibitors with entrectinib, a CYP3A4 substrate. If coadministration unavoidable, reduce entrectinib dose to 100 mg/day for patients aged 12 y or older with BSA >1.50m2. Resume previous entrectinib dose after discontinuing strong CYP3A inhibitor for 3-5 elimination half-lives.

• enzalutamide

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

• eplerenone

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

• erdafitinib

  Serious - Use Alternative (2)nelfinavir will increase the level or effect of erdafitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration with strong CYP3A4 inhibitors, monitor closely for adverse reactions and consider decreasing dose accordingly. If strong CYP3A4 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities.
  
  erdafitinib will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If coadministration unavoidable, separate administration by at least 6 hr before or after administration of P-gp substrates with narrow therapeutic index.

• ergonovine

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

• ergotamine

  Serious - Use Alternative (2)nelfinavir increases levels of ergotamine by decreasing metabolism. Contraindicated.
  
  nelfinavir will increase the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erlotinib

  Monitor Closely (1)nelfinavir will increase 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 nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)erythromycin base will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  nelfinavir will increase the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin ethylsuccinate

  Monitor Closely (1)erythromycin ethylsuccinate will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)erythromycin ethylsuccinate will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  nelfinavir will increase the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin lactobionate

  Monitor Closely (1)erythromycin lactobionate will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)erythromycin lactobionate will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  nelfinavir will increase the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• erythromycin stearate

  Monitor Closely (1)erythromycin stearate will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (2)erythromycin stearate will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  nelfinavir will increase the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• escitalopram

  Monitor Closely (1)nelfinavir increases levels of escitalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. Increased risk of serotonin syndrome.

• eslicarbazepine acetate

  Monitor Closely (2)eslicarbazepine acetate will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  eslicarbazepine acetate will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• esomeprazole

  Contraindicated (1)esomeprazole decreases levels of nelfinavir by unspecified interaction mechanism. Contraindicated. Coadministration may lead to loss of nelfinavir virologic response and development of resistance; mechanism may be CYP2C19 inhibition of nelfinavir conversion to active M8 metabolite, and also PPIs decreasing gastric pH resulting in decreased nelfinavir absorption.

• estradiol

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

• estradiol vaginal

  Monitor Closely (1)nelfinavir will increase the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with CYP3A4 inhibitors may increase plasma concentrations of estrogens and toxicities.

• estrogens conjugated synthetic

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

• estrogens esterified

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

• estropipate

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

• eszopiclone

  Monitor Closely (1)nelfinavir increases levels of eszopiclone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce eszopiclone starting dose to 1 mg/day.

• ethinylestradiol

  Serious - Use Alternative (2)nelfinavir will increase the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  nelfinavir, ethinylestradiol. Other (see comment). Avoid or Use Alternate Drug. Comment: Significant changes (increase or decrease) can occur in estrogen plasma levels. Efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended. .

• ethosuximide

  Monitor Closely (1)nelfinavir increases levels of ethosuximide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• etonogestrel

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

• etoposide

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

• etravirine

  Contraindicated (1)etravirine increases levels of nelfinavir by decreasing metabolism. Contraindicated.Monitor Closely (2)nelfinavir will increase the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  etravirine will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• eucalyptus

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

• everolimus

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

• exenatide injectable solution

  Monitor Closely (1)nelfinavir decreases effects of exenatide injectable solution by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• exenatide injectable suspension

  Monitor Closely (1)nelfinavir decreases effects of exenatide injectable suspension by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors.

• famotidine

  Monitor Closely (1)famotidine will decrease the level or effect of nelfinavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• fedratinib

  Monitor Closely (2)fedratinib will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.
  
  fedratinib will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP2C19 substrates as necessary.Serious - Use Alternative (2)nelfinavir will increase the level or effect of fedratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid fedratinib coadministration with strong CYP3A4 inhibitors, decrease fedratinib dose to 200 mg/day. If CYP3A4 inhibitor discontinued, increase fedratinib dose to 300 mg/day for 2 weeks, and then 400 mg/day thereafter as tolerated.
  
  nelfinavir will increase the level or effect of fedratinib by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of fedratinib (a CYP3A4 and CYP2C19 substrate) with dual CYP3A4 and CYP2C19 inhibitor. Effect of coadministration of a dual CYP3A4 and CYP2C19 inhibitor with fedratinib has not been studied.

• felbamate

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

• felodipine

  Monitor Closely (2)nelfinavir will increase the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  felodipine will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• fentanyl

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl intranasal

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl transdermal

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fentanyl transmucosal

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of CYP3A4 inhibitors with fentanyl is necessary, monitor patients for respiratory depression and sedation at frequent intervals and consider fentanyl dose adjustments until stable drug effects are achieved.

• fesoterodine

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

• fexinidazole

  Monitor Closely (1)fexinidazole will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)nelfinavir will decrease the level or effect of fexinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration, monitor fexinidazole for decreased efficacy owing to decreased plasma concentrations of active M1 and M2 metabolites.
  
  fexinidazole will increase the level or effect of nelfinavir 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)nelfinavir will increase the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• finerenone

  Contraindicated (1)nelfinavir will increase the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• flibanserin

  Contraindicated (1)nelfinavir will increase the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of flibanserin with moderate or strong CYP3A4 inhibitors is contraindicated. Severe hypotension or syncope can occur.

• fluconazole

  Monitor Closely (1)fluconazole will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fludrocortisone

  Monitor Closely (1)nelfinavir will increase the level or effect of fludrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• flunisolide inhaled

  Monitor Closely (1)nelfinavir will increase the level or effect of flunisolide inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• flurazepam

  Monitor Closely (1)nelfinavir increases levels of flurazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Use alternatives if available. Consider lowering benzodiazepine dose.

• fluticasone furoate

  Monitor Closely (1)nelfinavir will increase the level or effect of fluticasone furoate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inhibitors may increase fluticasone systemic exposure

• fluticasone inhaled

  Monitor Closely (1)nelfinavir will increase the level or effect of fluticasone inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inhibitors may increase fluticasone systemic exposure

• fluticasone intranasal

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of fluticasone intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inhibitors may increase systemic corticosteroid adverse effects; monitor for signs/symptoms of high corticosteroid concentrations including Cushing type signs/symptoms.

• fluvastatin

  Monitor Closely (1)nelfinavir increases toxicity of fluvastatin by Other (see comment). Use Caution/Monitor. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• fluvoxamine

  Monitor Closely (1)fluvoxamine will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• fosamprenavir

  Monitor Closely (3)fosamprenavir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  fosamprenavir and nelfinavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• fosphenytoin

  Monitor Closely (2)fosphenytoin will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  fosphenytoin will decrease the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• fostamatinib

  Monitor Closely (2)fostamatinib will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Concomitant use of fostamatinib may increase concentrations of P-gp substrates. Monitor for toxicities of the P-gp substrate drug that may require dosage reduction when given concurrently with fostamatinib.
  
  nelfinavir will increase the level or effect of fostamatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A4 inhibitors may increase exposure to R406 (fostamatinib major active metabolite). Monitor for toxicities that may require fostamatinib dose reduction.

• galantamine

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

• ganaxolone

  Minor (1)nelfinavir, ganaxolone. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. Changes in ganaxolone exposures when coadministered with strong, moderate, or weak CYP3A4 inhibitors are not expected to be clinically significant.

• garlic

  Monitor Closely (1)garlic decreases levels of nelfinavir by unknown mechanism. Use Caution/Monitor.

• gefitinib

  Monitor Closely (1)nelfinavir increases levels of gefitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of strong CYP3A4 inhibitors may increase risk for gefitinib adverse effects.

• gilteritinib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of gilteritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternatives to any strong CYP3A4 inhibitor when coadministered with gilteritinib. If such a combination cannot be avoided, closely monitor for gilteritinib-related adverse effects. Interrupt and reduce gilteritinib dosage in patients with serious or life-threatening toxicity.

• glasdegib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of glasdegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Consider alternate therapies that are not strong CYP3A inhibitors or monitor for increased risk of adverse effects, including QTc interval prolongation.

• glecaprevir/pibrentasvir

  Monitor Closely (3)nelfinavir will increase the level or effect of glecaprevir/pibrentasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of glecaprevir/pibrentasvir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  glecaprevir/pibrentasvir will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• glimepiride

  Monitor Closely (1)nelfinavir decreases effects of glimepiride by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• glipizide

  Monitor Closely (1)nelfinavir decreases effects of glipizide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• glyburide

  Monitor Closely (1)nelfinavir decreases effects of glyburide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• grapefruit

  Monitor Closely (1)grapefruit will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• griseofulvin

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

• guanfacine

  Monitor Closely (1)nelfinavir will increase the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inhibitors significantly increase guanfacine plasma concentrations. FDA-approved labeling for extended-release (ER) guanfacine recommends that, if coadministered, the guanfacine dosage should be decreased to half of the recommended dose. Specific recommendations for immediate-release (IR) guanfacine are not available.

• haloperidol

  Monitor Closely (1)nelfinavir will increase the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• hydrocodone

  Monitor Closely (1)nelfinavir will increase the level or effect of hydrocodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with CYP3A4 inhibitors may increase hydrocodone plasma concentrations and can result in potentially fatal respiratory depression

• hydrocortisone

  Monitor Closely (1)nelfinavir will increase the level or effect of hydrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• hydroxyprogesterone caproate

  Monitor Closely (1)nelfinavir will increase the level or effect of hydroxyprogesterone caproate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ibrutinib

  Serious - Use Alternative (1)nelfinavir increases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of ibrutinib and strong CYP3A4 inhibitors. If a strong CYP3A4 inhibitor must be used short-term (eg, anti-infectives for =7 days), interrupt ibrutinib therapy until strong CYP3A4 inhibitor is discontinued.

• ibuprofen/famotidine

  Monitor Closely (1)ibuprofen/famotidine will decrease the level or effect of nelfinavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• idelalisib

  Serious - Use Alternative (2)nelfinavir will increase the level or effect of idelalisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministered with strong CYP3A inhibitors, monitor for signs of idelalisib toxicity; follow recommendations for dosage modifications if adverse reactions occur
  
  idelalisib will increase the level or effect of nelfinavir 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)nelfinavir will decrease the level or effect of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of CYP3A4 inhibitors may decrease the metabolism of ifosfamide to its active alkylating metabolites and decrease the efficacy of ifosfamide.
  
  nelfinavir will decrease the level or effect of ifosfamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Coadministration of ifosfamide with CYP2B6 inhibitors may decrease metabolism of ifosfamide to its metabolite, potentially reducing ifosfamide therapeutic effects.

• iloperidone

  Monitor Closely (2)nelfinavir will increase the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  iloperidone increases levels of nelfinavir 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.

• imatinib

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

• imipramine

  Monitor Closely (1)nelfinavir will increase the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• indacaterol, inhaled

  Monitor Closely (1)nelfinavir increases levels of indacaterol, inhaled by Other (see comment). Use Caution/Monitor. Comment: Data suggests that systemic clearance is influenced by modulation of both P-gp and CYP3A4 activities. No dose adjustment is warranted at the 75 mcg dose.

• indinavir

  Monitor Closely (3)indinavir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  indinavir will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  indinavir and nelfinavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.Serious - Use Alternative (1)nelfinavir will increase the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• infigratinib

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

• insulin aspart

  Monitor Closely (1)nelfinavir decreases effects of insulin aspart by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• insulin degludec

  Monitor Closely (1)nelfinavir decreases effects of insulin degludec by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. HIV protease inhibitors may cause new onset diabetes mellitus (DM), exacerbate existing DM, and cause hyperglycemia due to insulin resistance.

• insulin degludec/insulin aspart

  Monitor Closely (1)nelfinavir decreases effects of insulin degludec/insulin aspart by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. HIV protease inhibitors may cause new onset diabetes mellitus (DM), exacerbate existing DM, and cause hyperglycemia due to insulin resistance.

• insulin detemir

  Monitor Closely (1)nelfinavir decreases effects of insulin detemir by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• insulin glargine

  Monitor Closely (1)nelfinavir decreases effects of insulin glargine by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• insulin glulisine

  Monitor Closely (1)nelfinavir decreases effects of insulin glulisine by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• insulin inhaled

  Monitor Closely (1)nelfinavir decreases effects of insulin inhaled by pharmacodynamic antagonism. Modify Therapy/Monitor Closely. HIV protease inhibitors may cause new onset diabetes mellitus (DM), exacerbate existing DM, and cause hyperglycemia due to insulin resistance.

• insulin lispro

  Monitor Closely (1)nelfinavir decreases effects of insulin lispro by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• insulin NPH

  Monitor Closely (1)nelfinavir decreases effects of insulin NPH by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• insulin regular human

  Monitor Closely (1)nelfinavir decreases effects of insulin regular human by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• irinotecan

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

• irinotecan liposomal

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• isavuconazonium sulfate

  Contraindicated (1)nelfinavir will increase the level or effect of isavuconazonium sulfate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• isoniazid

  Monitor Closely (1)isoniazid will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• isradipine

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

• istradefylline

  Monitor Closely (3)istradefylline will increase the level or effect of nelfinavir 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.
  
  istradefylline will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of P-gp substrates in clinical trials. Consider dose reduction of sensitive P-gp substrates.
  
  nelfinavir will increase the level or effect of istradefylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Do not exceed istradefylline 20 mg/day if coadministered with strong CYP3A4 inhibitors.

• itraconazole

  Monitor Closely (2)itraconazole will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
  
  itraconazole will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely.Minor (1)nelfinavir will increase the level or effect of itraconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ivabradine

  Contraindicated (1)nelfinavir will increase the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of ivabradine with strong CYP3A4 inhibitors is contraindicated.

• ivacaftor

  Monitor Closely (2)ivacaftor increases levels of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Ivacaftor and its M1 metabolite has the potential to inhibit P-gp; may significantly increase systemic exposure to sensitive P-gp substrates with a narrow therapeutic index.
  
  nelfinavir will increase the level or effect of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce ivacaftor dose if coadministered with strong CYP3A4 inhibitors. See specific ivacaftor-containing product for precise dosage modification.

• ivosidenib

  Serious - Use Alternative (2)nelfinavir will increase the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of strong CYP3A4 inhibitors with ivosidenib or replace with alternate therapies. If coadministration of a strong CYP3A4 inhibitor is unavoidable, reduce ivosidenib dose to 250 mg qDay. If the strong inhibitor is discontinued, increase ivosidenib dose (after at least 5 half-lives of the strong CYP3A4 inhibitor) to the recommended dose of 500 mg qDay. Monitor for increased risk of QTc interval prolongation.
  
  ivosidenib will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sensitive CYP3A4 substrates with ivosidenib or replace with alternative therapies. If coadministration is unavoidable, monitor patients for loss of therapeutic effect of these drugs.

• ixabepilone

  Monitor Closely (1)nelfinavir will increase the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ixazomib

  Minor (1)nelfinavir, ixazomib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. In clinical trials, coadministration of ixazomib with strong CYP3A inhibitors did not result in a clinically meaningful change in the systemic exposure of ixazomib.

• ketamine

  Monitor Closely (1)nelfinavir will decrease the level or effect of ketamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.

• ketoconazole

  Monitor Closely (2)ketoconazole will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  ketoconazole will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Minor (1)nelfinavir will increase the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• lacosamide

  Monitor Closely (1)nelfinavir, lacosamide. Either increases levels of the other by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider decreasing lacosamide dose when coadministered with strong CYP3A4 inhibitors.

• lamivudine

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

• lansoprazole

  Contraindicated (1)lansoprazole decreases levels of nelfinavir by unspecified interaction mechanism. Contraindicated. Coadministration may lead to loss of nelfinavir virologic response and development of resistance; mechanism may be CYP2C19 inhibition of nelfinavir conversion to active M8 metabolite, and also PPIs decreasing gastric pH resulting in decreased nelfinavir absorption.Minor (1)nelfinavir will increase the level or effect of lansoprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• lapatinib

  Monitor Closely (3)lapatinib will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  lapatinib will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• larotrectinib

  Serious - Use Alternative (1)nelfinavir will increase 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 inhibitors is unavoidable, reduce larotrectinib dose by 50%. Resume prior larotrectinib dose once CYP3A4 inhibitor discontinued for 3-5 half-lives.

• lasmiditan

  Serious - Use Alternative (1)lasmiditan increases levels of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• lefamulin

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of lefamulin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lefamulin with strong CYP3A inhibitors.

• lemborexant

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lemborexant with moderate or strong CYP3A inhibitors.

• letermovir

  Monitor Closely (2)nelfinavir increases levels of letermovir by decreasing metabolism. Use Caution/Monitor. Coadminstration of letermovir, an OATP1B1/3 substrate, with OATP1B1/3 inhibitors may increase letermovir plasma concentrations.
  
  letermovir increases levels of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• levamlodipine

  Monitor Closely (1)nelfinavir will increase the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration with moderate and strong CYP3A inhibitors results in increased systemic exposure to amlodipine and may require dose reduction. Monitor for symptoms of hypotension and edema when amlodipine is coadministered with CYP3A inhibitors to determine the need for dose adjustment.

• levoketoconazole

  Monitor Closely (2)levoketoconazole will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  levoketoconazole will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Minor (1)nelfinavir will increase the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• levomilnacipran

  Monitor Closely (1)nelfinavir will increase the level or effect of levomilnacipran by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Do not exceed 80 mg/day of levomilnacipran when coadministered with strong CYP3A4 inhibitors

• levonorgestrel intrauterine

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of levonorgestrel intrauterine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• levonorgestrel oral/ethinylestradiol/ferrous bisglycinate

  Serious - Use Alternative (1)nelfinavir, levonorgestrel oral/ethinylestradiol/ferrous bisglycinate. Other (see comment). Avoid or Use Alternate Drug. Comment: Significant changes (increase or decrease) can occur in estrogen plasma levels. Efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.

• linagliptin

  Monitor Closely (2)nelfinavir decreases effects of linagliptin by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .
  
  nelfinavir will increase the level or effect of linagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• liraglutide

  Monitor Closely (1)nelfinavir decreases effects of liraglutide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• lomitapide

  Contraindicated (1)nelfinavir increases levels of lomitapide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Increases lomitapide levels several folds.Monitor Closely (1)lomitapide increases levels of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing dose when used concomitantly with lomitapide.

• lonafarnib

  Contraindicated (1)nelfinavir will increase the level or effect of lonafarnib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Lonafarnib is a sensitive CYP3A4 substrate. Coadministration with strong or moderate CYP3A4 inhibitors is contraindicated.

• lopinavir

  Monitor Closely (1)nelfinavir will increase the level or effect of lopinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)lopinavir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• loratadine

  Monitor Closely (2)nelfinavir will increase the level or effect of loratadine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  loratadine will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• lorlatinib

  Serious - Use Alternative (2)lorlatinib will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  nelfinavir will increase the level or effect of lorlatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministering lorlatinib with strong CYP3A inhibitors. If unavoidable, reduce lorlatinib dose by 25 mg/day. If strong CYP3A inhibitor discontinued, increase to previous lorlatinib (dose after 3 plasma half-lives of strong CYP3A inhibitor). See monograph for further details.

• lovastatin

  Contraindicated (2)nelfinavir will increase the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors increase systemic statin exposure and risk of myopathy, including rhabdomyolysis
  
  lovastatin will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Contraindicated.

• lumacaftor/ivacaftor

  Monitor Closely (2)nelfinavir increases levels of lumacaftor/ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong CYP3A inhibitors do not impact lumacaftor exposure, but increased ivacaftor exposure by 4.3-fold. Due to the induction effect of lumacaftor on CYP3A, at steady-state the net exposure of ivacaftor is not expected to exceed that when given in the absence of lumacaftor at a dose of 150 mg q12hr (the approved dose of ivacaftor monotherapy). Therefore, no dose adjustment is necessary when CYP3A inhibitors are initiated in patients currently taking lumacaftor/ivacaftor. However, when initiating lumacaftor/ivacaftor in patients taking strong CYP3A inhibitors, reduce the dose to 1 tablet daily (lumacaftor 200 mg/ivacaftor 125 mg total daily dose) for the first week of treatment to allow for the steady-state induction effect of lumacaftor. Following this period, continue with the recommended daily dose. No dose adjustment is required for moderate or weak CYP3A4 inhibitors.
  
  lumacaftor/ivacaftor, nelfinavir. affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2C19 substrates. .

• lumateperone

  Monitor Closely (1)nelfinavir will increase the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce lumateperone dose to 10.5 mg/day if coadministered with strong CYP3A4 inhibitors.

• lumefantrine

  Monitor Closely (2)nelfinavir will increase the level or effect of lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  lumefantrine will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• lurasidone

  Contraindicated (1)nelfinavir increases levels of lurasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of lurasidone and strong CYP3A4 inhibitors is contraindicated.

• lurbinectedin

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

• macitentan

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of macitentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministering macitentan with strong CYP3A4 inhibitors

• maraviroc

  Monitor Closely (1)nelfinavir will increase the level or effect of maraviroc by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Decrease maraviroc dose to 150 mg BID when coadministered with strong CYP3A4 inhibitors

• marijuana

  Monitor Closely (2)marijuana will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of marijuana by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• mavacamten

  Contraindicated (1)nelfinavir will increase the level or effect of mavacamten by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors may increase mavacamten systemic exposure, resulting in heart failure due to systolic dysfunction. Monitor Closely (1)nelfinavir will increase the level or effect of mavacamten by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Inititiation of weak CYP2C19 inhibitors may require decreased mavacamten dose.

• medroxyprogesterone

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

• mefloquine

  Serious - Use Alternative (1)nelfinavir increases levels of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Potential for increased toxicity. Avoid coadministration during and for 15 weeks after discontinuing mefloquine. .

• meperidine

  Monitor Closely (1)nelfinavir increases levels of meperidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• mestranol

  Monitor Closely (2)nelfinavir will increase the level or effect of mestranol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir decreases levels of mestranol by increasing metabolism. Use Caution/Monitor. May result in contraceptive failure.

• metformin

  Monitor Closely (1)nelfinavir decreases effects of metformin by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• methadone

  Monitor Closely (1)nelfinavir will increase the level or effect of methadone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• methylergonovine

  Contraindicated (2)nelfinavir increases levels of methylergonovine by decreasing metabolism. Contraindicated. Potential for serious and/or life threatening reactions (eg, ergot toxicity characterized by peripheral vasospasm, and ischemia of the extremities and other tissues).
  
  nelfinavir will increase the level or effect of methylergonovine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• methylprednisolone

  Monitor Closely (1)nelfinavir will increase the level or effect of methylprednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• metronidazole

  Monitor Closely (1)metronidazole will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• miconazole vaginal

  Monitor Closely (1)miconazole vaginal will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• midazolam

  Contraindicated (1)nelfinavir increases levels of midazolam by decreasing metabolism. Contraindicated. Potential for serious and/or life threatening reactions (eg, prolonged or increased sedation, or respiratory depression).Monitor Closely (1)nelfinavir will increase the level or effect of midazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• midazolam intranasal

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of midazolam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of strong CYP3A4 inhibitors with midazolam intranasal causes higher midazolam systemic exposure, which may prolong sedation.

• midostaurin

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of midostaurin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong CYP3A4 inhibitors cannot be avoided, monitor midostaurin for increased risk of adverse reactions, especially during the first week of treatment.

• mifepristone

  Monitor Closely (2)nelfinavir, mifepristone. Either increases levels of the other by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Do not exceed mifepristone 300 mg/day for Cushing syndrome when coadministered with strong CYP3A4 inhibitors.
  
  mifepristone will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• miglitol

  Monitor Closely (1)nelfinavir decreases effects of miglitol by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• mipomersen

  Monitor Closely (1)mipomersen, nelfinavir. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Both drugs have potential to increase hepatic enzymes; monitor LFTs.

• mirtazapine

  Monitor Closely (1)nelfinavir increases levels of mirtazapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• mitotane

  Monitor Closely (1)mitotane decreases levels of nelfinavir 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 (1)nelfinavir will increase the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• modafinil

  Monitor Closely (1)nelfinavir will increase the level or effect of modafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• mometasone inhaled

  Monitor Closely (1)nelfinavir increases levels of mometasone inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. Increased risk of Cushing's syndrome or adrenal suppression.

• mometasone, intranasal

  Monitor Closely (1)nelfinavir will increase the level or effect of mometasone, intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• montelukast

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

• nafcillin

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

• naldemedine

  Monitor Closely (2)nelfinavir increases levels of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with strong or moderate CYP3A4 inhibitors.
  
  nelfinavir increases levels of naldemedine by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor naldemedine for potential adverse effects if coadministered with P-gp inhibitors.

• naloxegol

  Contraindicated (1)nelfinavir will increase the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of naloxegol with strong CYP3A4 inhibitors can significantly increase naloxegol systemic exposure which may precipitate opioid withdrawal symptoms

• nateglinide

  Monitor Closely (1)nelfinavir decreases effects of nateglinide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• nefazodone

  Monitor Closely (3)nefazodone will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nefazodone will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• neratinib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inhibitors.

• netupitant/palonosetron

  Monitor Closely (1)nelfinavir will increase the level or effect of netupitant/palonosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Netupitant is mainly metabolized by CYP3A4; no dosage adjustment is required

• nevirapine

  Monitor Closely (3)nevirapine will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir and nevirapine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of nevirapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nicardipine

  Monitor Closely (2)nelfinavir will increase the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nicardipine will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• nifedipine

  Monitor Closely (3)nifedipine will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nifedipine will decrease the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  nelfinavir will increase the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Consider initiating nifedipine at the lowest dose available if given concomitantly with this medication

• nilotinib

  Monitor Closely (3)nelfinavir will increase the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nilotinib will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nilotinib will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• nimodipine

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

• nintedanib

  Monitor Closely (1)nelfinavir increases levels of nintedanib by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. If nintedanib adverse effects occur, management may require interruption, dose reduction, or discontinuation of therapy .

• nirmatrelvir

  Monitor Closely (1)nirmatrelvir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Patients on ritonavir- or cobicistat-containing HIV regimens should continue their treatment as indicated. Monitor for increased nirmatrelvir/ritonavir or protease inhibitor adverse events with concomitant use.

• nirmatrelvir/ritonavir

  Monitor Closely (1)nirmatrelvir/ritonavir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Patients on ritonavir- or cobicistat-containing HIV regimens should continue their treatment as indicated. Monitor for increased nirmatrelvir/ritonavir or protease inhibitor adverse events with concomitant use.

• nisoldipine

  Monitor Closely (1)nelfinavir will increase the level or effect of nisoldipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• nitrendipine

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

• nizatidine

  Monitor Closely (1)nizatidine will decrease the level or effect of nelfinavir by increasing gastric pH. Applies only to oral form of both agents. Use Caution/Monitor.

• norethindrone

  Monitor Closely (1)nelfinavir will increase the level or effect of norethindrone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• olaparib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong CYP3A inhibitors cannot be avoided, reduce olaparib dose to 150 mg (capsule) or 100 mg (tablet) PO BID. Do not substitute tablets with capsules.

• oliceridine

  Monitor Closely (1)nelfinavir will increase the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If concomitant use is necessary, may require less frequent oliceridine dosing. Closely monitor for respiratory depression and sedation and titrate subsequent doses accordingly. If inhibitor is discontinued, consider increase oliceridine dosage until stable drug effects are achieved. Monitor for signs of opioid withdrawal.

• ombitasvir/paritaprevir/ritonavir

  Monitor Closely (1)nelfinavir will increase the level or effect of ombitasvir/paritaprevir/ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC)

  Monitor Closely (1)nelfinavir will increase the level or effect of ombitasvir/paritaprevir/ritonavir & dasabuvir (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• omeprazole

  Contraindicated (1)omeprazole decreases levels of nelfinavir by unspecified interaction mechanism. Contraindicated. Coadministration may lead to loss of nelfinavir virologic response and development of resistance; mechanism may be CYP2C19 inhibition of nelfinavir conversion to active M8 metabolite, and also PPIs decreasing gastric pH resulting in decreased nelfinavir absorption.

• ondansetron

  Monitor Closely (1)nelfinavir will increase the level or effect of ondansetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP-450 inhibitors may decrease clearance of ondansetron. However, no dosage adjustment for ondansetron is recommended

• orlistat

  Monitor Closely (1)orlistat will decrease the level or effect of nelfinavir 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 (1)nelfinavir will increase the level or effect of osilodrostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce dose of osilodrostat, a CYP3A4 substrate, by half when coadministered with a strong CYP3A4 inhibitor.

• osimertinib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of osimertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of osimertinib with strong CYP3A4 inhibitors. If no other alternative treatment exists, monitor patient more closely for adverse effects.

• ospemifene

  Monitor Closely (1)nelfinavir increases levels of ospemifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• oxcarbazepine

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

• oxybutynin

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

• oxycodone

  Serious - Use Alternative (1)nelfinavir increases levels of oxycodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Oxycodone dose reduction may be warranted when coadministered with strong CYP3A4 inhibitors.

• paclitaxel

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

• paclitaxel protein bound

  Minor (1)nelfinavir will increase the level or effect of paclitaxel protein bound by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• pacritinib

  Contraindicated (1)nelfinavir will increase the level or effect of pacritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• palbociclib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of palbociclib with strong CYP3A inhibitors. If unable to avoid, reduce palbociclib dose to 75 mg/day.

• panobinostat

  Monitor Closely (1)nelfinavir increases levels of panobinostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce panobinostat starting dose to 10 mg if coadministered with strong CYP3A4 inhibitors.

• pantoprazole

  Contraindicated (1)pantoprazole decreases levels of nelfinavir by unspecified interaction mechanism. Contraindicated. Coadministration may lead to loss of nelfinavir virologic response and development of resistance; mechanism may be CYP2C19 inhibition of nelfinavir conversion to active M8 metabolite, and also PPIs decreasing gastric pH resulting in decreased nelfinavir absorption.

• parecoxib

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

• paricalcitol

  Monitor Closely (1)nelfinavir increases levels of paricalcitol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• pazopanib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of pazopanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of pazopanib with strong CYP3A4 inhibitors if possible; if must coadminister, decrease pazopanib dose to 400 mg/day

• pemigatinib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pemigatinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pemigatinib dose.

• pentobarbital

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

• perampanel

  Monitor Closely (1)nelfinavir will increase the level or effect of perampanel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• pexidartinib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors is unavoidable, reduce pexidartinib dose (refer to drug monograph dosage modifications). After discontinuing the CYP3A4 inhibitor for 3 elimination half-lives, may resume previous pexidartinib dose.

• phenobarbital

  Monitor Closely (2)phenobarbital will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  phenobarbital will decrease the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• phenytoin

  Monitor Closely (2)phenytoin will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  phenytoin will decrease the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• pimavanserin

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease dose to 17 mg/day if pimavanserin is coadministered with strong CYP3A4 inhibitors.

• pimozide

  Contraindicated (1)nelfinavir increases levels of pimozide by decreasing metabolism. Contraindicated. Potential for serious and/or life-threatening reactions (eg, cardiac arrhythmias).Minor (1)nelfinavir will increase the level or effect of pimozide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• pioglitazone

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

• pitavastatin

  Monitor Closely (1)nelfinavir increases toxicity of pitavastatin by Other (see comment). Use Caution/Monitor. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• polatuzumab vedotin

  Monitor Closely (1)nelfinavir will increase the level or effect of polatuzumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Polatuzumab undergoes catabolism to small peptides, amino acids, monomethyl auristatin E (MMAE), and unconjugated MMAE-related catabolites. MMAE is a CYP3A4 substrate. Coadministration of polatuzumab vedotin with a strong CYP3A4 inhibitor may increase unconjugated MMAE AUC, which may increase polatuzumab vedotin toxicities.

• pomalidomide

  Serious - Use Alternative (2)nelfinavir increases levels of pomalidomide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  nelfinavir increases levels of pomalidomide by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• ponatinib

  Monitor Closely (1)ponatinib increases levels of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nelfinavir increases levels of ponatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Decrease ponatinib starting dose to 30 mg qDay if coadministration with strong CYP3A4 inhibitors cannot be avoided.

• posaconazole

  Monitor Closely (1)posaconazole will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• pralsetinib

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

• pramlintide

  Monitor Closely (1)nelfinavir decreases effects of pramlintide by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• pravastatin

  Monitor Closely (1)nelfinavir increases toxicity of pravastatin by Other (see comment). Use Caution/Monitor. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• praziquantel

  Monitor Closely (1)nelfinavir will increase the level or effect of praziquantel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• prednisolone

  Monitor Closely (1)nelfinavir will increase the level or effect of prednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• prednisone

  Monitor Closely (1)nelfinavir will increase the level or effect of prednisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• primidone

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

• progesterone intravaginal gel

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of progesterone intravaginal gel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• progesterone micronized

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of progesterone micronized by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• progesterone, natural

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of progesterone, natural by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• propafenone

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

• quazepam

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

• quercetin

  Monitor Closely (1)quercetin will decrease the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• quetiapine

  Monitor Closely (1)nelfinavir will increase the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• quinidine

  Monitor Closely (1)nelfinavir will increase the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (2)nelfinavir increases levels of quinidine by decreasing metabolism. Contraindicated.
  
  quinidine will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• quinine

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

• quinupristin/dalfopristin

  Monitor Closely (1)quinupristin/dalfopristin will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rabeprazole

  Contraindicated (1)rabeprazole decreases levels of nelfinavir by unspecified interaction mechanism. Contraindicated. Coadministration may lead to loss of nelfinavir virologic response and development of resistance; mechanism may be CYP2C19 inhibition of nelfinavir conversion to active M8 metabolite, and also PPIs decreasing gastric pH resulting in decreased nelfinavir absorption.Minor (1)nelfinavir will increase the level or effect of rabeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.

• ramelteon

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

• ranolazine

  Monitor Closely (1)ranolazine will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nelfinavir will increase the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• red yeast rice

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of red yeast rice by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. May increase creatine kinase levels and increase risk of myopathy or rhabdomyolysis; red yeast rice contains monocolin K (reportedly identical to lovastatin)

• regorafenib

  Contraindicated (1)nelfinavir, regorafenib. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Strong CYP3A4 inhibitors increase regorafenib levels and decrease exposure of the active metabolites M-2 and M-5.

• repaglinide

  Monitor Closely (1)nelfinavir will increase the level or effect of repaglinide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• ribociclib

  Monitor Closely (1)ribociclib will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)nelfinavir will increase the level or effect of ribociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If a strong CYP3A inhibitor must be coadministered with ribociclib, reduce the ribociclib starting dose to 400 mg/day.

• rifabutin

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

• rifampin

  Contraindicated (1)rifampin decreases levels of nelfinavir by increasing metabolism. Contraindicated. Decreased nelfinavir plasma concentrations may lead to loss of therapeutic effect and possible development of resistance to nelfinavir or other coadministered antiretroviral agents.

• rifapentine

  Monitor Closely (1)rifapentine will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)rifapentine decreases levels of nelfinavir by increasing metabolism. Contraindicated.

• rifaximin

  Monitor Closely (1)nelfinavir increases levels of rifaximin by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• rilpivirine

  Monitor Closely (1)nelfinavir increases levels of rilpivirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rimegepant

  Serious - Use Alternative (2)nelfinavir will increase the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  nelfinavir will increase the level or effect of rimegepant by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug.

• riociguat

  Serious - Use Alternative (3)nelfinavir will increase the level or effect of riociguat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
  
  nelfinavir will increase the level or effect of riociguat by decreasing metabolism. Avoid or Use Alternate Drug. Coadministration of riociguat (substrate of CYP isoenzymes 1A1, 2C8, 3A, 2J2) with strong CYP inhibitors may require a decreased initial dose of 0.5 mg PO TID; monitor for signs of hypotension and reduce dose if needed
  
  nelfinavir will increase the level or effect of riociguat by Other (see comment). Avoid or Use Alternate Drug. Coadministration of riociguat (an ABCG2 [BCRP] substrate) with strong ABCG2 inhibitors may require a decreased initial dose of 0.5 mg PO TID; monitor for signs of hypotension and reduce dose if needed

• ripretinib

  Monitor Closely (1)nelfinavir will increase the level or effect of ripretinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with a strong CYP3A inhibitor will increase systemic exposure to ripretinib and its active metabolite (DP-5439), which may increase risk of adverse reactions.

• ritonavir

  Monitor Closely (4)nelfinavir will increase the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  ritonavir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  ritonavir will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  nelfinavir and ritonavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• rivaroxaban

  Monitor Closely (1)nelfinavir increases levels of rivaroxaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid concomitant use of rivaroxaban and combined Pgp and strong CYP3A4 inhibitors. Combination may lead to significant increases in rivaroxaban levels and increase bleeding risk.

• romidepsin

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of romidepsin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong 3A4 inhibitors should be avoided if possible.

• rosiglitazone

  Monitor Closely (1)nelfinavir decreases effects of rosiglitazone by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• rosuvastatin

  Serious - Use Alternative (1)nelfinavir increases toxicity of rosuvastatin by Other (see comment). Avoid or Use Alternate Drug.

• rucaparib

  Monitor Closely (1)rucaparib will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• rufinamide

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

• ruxolitinib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce ruxolitinib starting dose to 10 mg BID with platelet count 100 X 10^9/L or more and concurrent use of strong CYP3A4 inhibitors; avoid with platelet counts <100 X 10^9/L

• ruxolitinib topical

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce ruxolitinib starting dose to 10 mg BID with platelet count 100 X 10^9/L or more and concurrent use of strong CYP3A4 inhibitors; avoid with platelet counts <100 X 10^9/L

• sacubitril/valsartan

  Monitor Closely (1)nelfinavir will increase the level or effect of sacubitril/valsartan by Other (see comment). Use Caution/Monitor. The results from an in vitro study with human liver tissue indicate that valsartan is a substrate of the hepatic uptake transporter OATP1B1; coadministration with OATP1B1 inhibitors may increase valsartan systemic exposure

• salmeterol

  Contraindicated (1)nelfinavir increases levels of salmeterol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Potential for increased toxicity. .

• saquinavir

  Monitor Closely (2)nelfinavir will increase the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir and saquinavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.Serious - Use Alternative (1)saquinavir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sarecycline

  Monitor Closely (1)sarecycline will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Monitor for toxicities of P-gp substrates that may require dosage reduction when coadministered with P-gp inhibitors.

• saxagliptin

  Monitor Closely (1)nelfinavir will increase the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Limit saxagliptin dose to 2.5 mg/day when coadministered with strong CYP3A4 inhibitors

• secobarbital

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

• selpercatinib

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

• selumetinib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with strong or moderate CYP3A4 inhibitors cannot be avoided, reduce selumetinib dosage (refer to selumetinib monograph for further information). After discontinuation of the strong or moderate CYP3A4 inhibitor for 3 elimination half-lives, resume selumetinib dose that was taken before initiating the inhibitor.

• sertraline

  Monitor Closely (1)nelfinavir increases levels of sertraline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• sildenafil

  Contraindicated (1)nelfinavir will increase the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• silodosin

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

• simvastatin

  Contraindicated (3)nelfinavir will increase the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
  
  simvastatin will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Contraindicated.
  
  nelfinavir increases toxicity of simvastatin by Other (see comment). Contraindicated. Comment: OATP1B1 inhibitors may increase risk of myopathy.

• siponimod

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a moderate or strong CYP3A4 inhibitor PLUS a moderate or strong CYP2C9 inhibitor is not recommended.

• sirolimus

  Monitor Closely (1)sirolimus will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nelfinavir will increase the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sitagliptin

  Monitor Closely (1)nelfinavir decreases effects of sitagliptin by Other (see comment). Use Caution/Monitor. Comment: Reports of hyperglycemia due to insulin resistance with protease inhibitors. .

• sodium zirconium cyclosilicate

  Monitor Closely (1)sodium zirconium cyclosilicate will decrease the level or effect of nelfinavir by increasing gastric pH. Applies only to oral form of both agents. Modify Therapy/Monitor Closely. Check specific recommendations for drugs that exhibit pH-dependent solubility that may affect their systemic exposure and efficacy. In general, administer drugs at least 2 hr before or after sodium zirconium cyclosilicate.

• sofosbuvir/velpatasvir

  Monitor Closely (1)nelfinavir will increase the level or effect of sofosbuvir/velpatasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• solifenacin

  Monitor Closely (1)nelfinavir will increase the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• sonidegib

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sonidegib with strong CYP3A4 inhibitors.

• sorafenib

  Monitor Closely (1)nelfinavir will increase the level or effect of sorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• sotorasib

  Serious - Use Alternative (1)sotorasib will decrease the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If use is unavoidable, refer to the prescribing information of the P-gp substrate for dosage modifications.

• St John's Wort

  Contraindicated (1)St John's Wort will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.Monitor Closely (1)St John's Wort will decrease the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)St John's Wort decreases levels of nelfinavir by increasing metabolism. Contraindicated.

• stavudine

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

• stiripentol

  Monitor Closely (3)stiripentol, nelfinavir. 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 will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the dose of CYP2C19 substrates, if adverse reactions are experienced when administered concomitantly with stiripentol.
  
  stiripentol will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Modify Therapy/Monitor Closely. Consider reducing the dose of P-glycoprotein (P-gp) substrates, if adverse reactions are experienced when administered concomitantly with stiripentol.Serious - Use Alternative (1)nelfinavir will increase the level or effect of stiripentol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• sufentanil

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

• sufentanil SL

  Monitor Closely (1)nelfinavir will increase the level or effect of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of sufentanil SL with any CYP3A4 inhibitor may increase sufentanil plasma concentration, and, thereby increase or prolonged adverse effects, including potentially fatal respiratory depression.

• sunitinib

  Monitor Closely (1)nelfinavir will increase the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• suvorexant

  Serious - Use Alternative (1)nelfinavir increases levels of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Suvorexant not recommended with use of strong CYP3A4 inhibitors.

• tacrolimus

  Monitor Closely (2)nelfinavir will increase the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  tacrolimus will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• tacrolimus ointment

  Monitor Closely (1)nelfinavir will increase the level or effect of tacrolimus ointment by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tadalafil

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Stop tadalafil >24 hours prior to protease inhibitor (PI) initiation, restart 7 days after PI initiation at 20 mg once daily, and increase to 40 mg once daily based on tolerability.

• tamoxifen

  Serious - Use Alternative (1)nelfinavir, tamoxifen. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP3A4 inhibition decreases metabolism of tamoxifen to N-desmethyl tamoxifen (active metabolite with similar biologic activity).

• tamsulosin

  Serious - Use Alternative (1)nelfinavir increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tasimelteon

  Monitor Closely (1)nelfinavir will increase the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tazemetostat

  Monitor Closely (1)tazemetostat will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)nelfinavir will increase the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• tecovirimat

  Monitor Closely (2)tecovirimat will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Tecovirimat is a weak inhibitor of CYP2C8 and CYP2C19. Monitor for adverse effects if coadministered with sensitive substrates of these enzymes.
  
  tecovirimat will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.

• temsirolimus

  Monitor Closely (1)nelfinavir will increase the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• teniposide

  Monitor Closely (1)nelfinavir will increase the level or effect of teniposide by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• tenofovir DF

  Monitor Closely (1)nelfinavir and tenofovir DF both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• tepotinib

  Serious - Use Alternative (2)nelfinavir will increase the level or effect of tepotinib by Other (see comment). Avoid or Use Alternate Drug. Interaction not studied clinically. Metabolism and data suggest drugs that are strong CYP3A4 and P-gp inhibitors may increase tepotinib (a P-gp and CYP3A4 substrate) effects and risk of toxicities.
  
  tepotinib will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If concomitant use unavoidable, reduce the P-gp substrate dosage if recommended in its approved product labeling.

• terbinafine

  Monitor Closely (1)nelfinavir will increase the level or effect of terbinafine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tezacaftor

  Monitor Closely (1)nelfinavir will increase the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust tezacaftor dosage regimen if coadministered with a strong CYP3A inhibitor.

• theophylline

  Monitor Closely (1)nelfinavir will increase the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tiagabine

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

• ticagrelor

  Monitor Closely (1)nelfinavir increases levels of ticagrelor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Ticagrelor is metabolized by CYP3A4/5. Avoid use with strong CYP3A inhibitors.

• tinidazole

  Monitor Closely (1)nelfinavir will increase the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tipranavir

  Contraindicated (1)tipranavir will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.Monitor Closely (2)nelfinavir will increase the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  nelfinavir and tipranavir both increase risk of immune reconstitution syndrome. Use Caution/Monitor.

• tisotumab vedotin

  Monitor Closely (1)nelfinavir increases levels of tisotumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tisotumab vedotin?s active metabolite (MMAE) is a CYP3A4 substrate. Coadministration with strong CYP3A4 inhibitors may increase unconjugated MMAE systemic exposure and increase risk of adverse effects.

• tofacitinib

  Serious - Use Alternative (1)nelfinavir increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Reduce tofacitinib dose to 5 mg qDay when coadministered with potent CYP3A4 inhibitors.

• tolterodine

  Monitor Closely (1)nelfinavir will increase the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tolvaptan

  Monitor Closely (1)tolvaptan will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nelfinavir will increase the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• topiramate

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

• topotecan

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of topotecan by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. Product labeling for PO topotecan recommends avoiding concomitant use of P-gp inhibitors; the interaction with IV topotecan may be less severe but is still likely of clinical significance

• toremifene

  Monitor Closely (1)nelfinavir increases levels of toremifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Metabolism of toremifene may be inhibited by drugs known to inhibit CYP3A4 hepatic enzymes.

• trabectedin

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

• tramadol

  Monitor Closely (1)nelfinavir increases levels of tramadol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• trazodone

  Monitor Closely (2)nelfinavir will increase the level or effect of trazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  trazodone will decrease the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• triamcinolone acetonide injectable suspension

  Monitor Closely (1)nelfinavir will increase the level or effect of triamcinolone acetonide injectable suspension by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• triazolam

  Contraindicated (1)nelfinavir increases levels of triazolam by decreasing metabolism. Contraindicated. Potential for serious and/or life threatening reactions (eg, prolonged or increased sedation, or respiratory depression).Monitor Closely (1)nelfinavir will increase the level or effect of triazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• triclabendazole

  Monitor Closely (1)triclabendazole will increase the level or effect of nelfinavir by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.

• trimipramine

  Monitor Closely (1)nelfinavir will increase the level or effect of trimipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• tucatinib

  Monitor Closely (1)tucatinib will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor. Consider reducing the dosage of P-gp substrates, where minimal concentration changes may lead to serious or life-threatening toxicities.Serious - Use Alternative (1)tucatinib will increase the level or effect of nelfinavir 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 nelfinavir by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely.

• ubrogepant

  Serious - Use Alternative (1)nelfinavir will increase the level or effect of ubrogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• ulipristal

  Monitor Closely (1)nelfinavir will increase the level or effect of ulipristal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• umeclidinium bromide/vilanterol inhaled

  Monitor Closely (1)nelfinavir will increase the level or effect of umeclidinium bromide/vilanterol inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Vilanterol is a CYP3A4 substrate; coadministration with potent CYP3A4 inhibitors may increase systemic exposure

• upadacitinib

  Monitor Closely (1)nelfinavir will increase the level or effect of upadacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution if upadacitinib is coadministered with strong CYP3A4 inhibitors.

• valbenazine

  Monitor Closely (1)nelfinavir will increase the level or effect of valbenazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce valbenazine dose to 40 mg once daily when coadministered with a strong CYP3A4 inhibitor.

• valsartan

  Monitor Closely (1)nelfinavir will increase the level or effect of valsartan by Other (see comment). Use Caution/Monitor. The results from an in vitro study with human liver tissue indicate that valsartan is a substrate of the hepatic uptake transporter OATP1B1; coadministration with OATP1B1 inhibitors may increase valsartan systemic exposure

• vardenafil

  Monitor Closely (1)nelfinavir will increase the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• velpatasvir

  Monitor Closely (1)nelfinavir will increase the level or effect of velpatasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• vemurafenib

  Monitor Closely (2)nelfinavir increases levels of vemurafenib by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.
  
  vemurafenib increases levels of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.Serious - Use Alternative (1)nelfinavir increases levels of vemurafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• venetoclax

  Contraindicated (1)nelfinavir will increase the level or effect of venetoclax by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Use of strong CYP3A4 inhibitors is contraindicated with venetoclax during the initial ramp-up dosing phase. If a strong CYP3A inhibitor must be used after the ramp-up phase, reduce the venetoclax dose by at least 75%.Serious - Use Alternative (1)nelfinavir will increase the level or effect of venetoclax by P-glycoprotein (MDR1) efflux transporter. Avoid or Use Alternate Drug. If a P-gp inhibitor must be used, reduce the venetoclax dose by at least 50%. Monitor more closely for signs of venetoclax toxicities.

• verapamil

  Monitor Closely (3)nelfinavir will increase the level or effect of verapamil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  verapamil will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
  
  verapamil will increase the level or effect of nelfinavir by P-glycoprotein (MDR1) efflux transporter. Use Caution/Monitor.

• vilanterol/fluticasone furoate inhaled

  Monitor Closely (1)nelfinavir will increase the level or effect of vilanterol/fluticasone furoate inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Fluticasone furoate and vilanterol are both CYP3A4 substrates; coadministration with potent CYP3A4 inhibitors may increase systemic exposure

• vilazodone

  Serious - Use Alternative (1)nelfinavir increases levels of vilazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If intolerable adverse effects occur when coadministered with moderate CYP3A4 inhibitors, reduce daily dose to 20 mg.

• vinblastine

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

• vincristine

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

• vincristine liposomal

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

• vinorelbine

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

• voclosporin

  Contraindicated (1)nelfinavir will increase the level or effect of voclosporin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.

• vonoprazan

  Serious - Use Alternative (1)vonoprazan will decrease the level or effect of nelfinavir by inhibition of GI absorption. Applies only to oral form of both agents. Avoid or Use Alternate Drug.

• vorapaxar

  Serious - Use Alternative (1)nelfinavir increases levels of vorapaxar by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• voriconazole

  Monitor Closely (1)nelfinavir will increase the level or effect of voriconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.Serious - Use Alternative (1)voriconazole will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.

• voxelotor

  Serious - Use Alternative (1)voxelotor will increase the level or effect of nelfinavir 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

  Monitor Closely (1)nelfinavir will increase the level or effect of voxilaprevir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• warfarin

  Monitor Closely (1)nelfinavir will increase the level or effect of warfarin by Other (see comment). Use Caution/Monitor. Warfarin's less potent R-enantiomer is metabolized in part by CYP3A4 (and also CYP1A2 and CYP2C19). Monitor INR more frequently if coadministered with inhibitors of these isoenzymes and adjust warfarin dose if needed.

• zafirlukast

  Monitor Closely (1)zafirlukast will increase the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.

• zaleplon

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

• zanubrutinib

  Monitor Closely (1)nelfinavir will increase the level or effect of zanubrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Reduce zanubrutinib (a CYP3A4 substrate) to 80 mg PO BID when coadministered with a moderate CYP3A4 inhibitor. Interrupt dose as recommended for adverse reactions. After discontinuing the CYP3A4 inhibitor, resume previous zanubrutinib dose.

• zidovudine

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

• zileuton

  Monitor Closely (1)nelfinavir increases levels of zileuton by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potential for increased toxicity. .

• ziprasidone

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

• zolpidem

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

• zonisamide

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