Dosing & Uses
Dosage Forms & Strengths
efavirenz/lamivudine/tenofovir DF (ie, tenofovir disoproxil fumarate)
tablet
- 400mg/300mg/300mg (Symfi Lo)
- 600mg/300mg/300mg (Symfi)
HIV Infection
Indicated as a complete antiretroviral (ART) regimen for HIV-1 infection
Combination consists of 2 nucleo(t)side reverse transcriptase inhibitors (NRTIs) (ie, lamivudine and tenofovir) and 1 non-nucleoside reverse transcriptase inhibitor (NNRTI) (ie, efavirenz)
1 tablet (efavirenz 400 mg/lamivudine 300 mg/tenofovir DF 300 mg) PO qHS OR
1 tablet (efavirenz 600 mg/lamivudine 300 mg/tenofovir DF 300 mg) PO qHS
Also see administration
Dosage Modifications
Hepatic impairment
- Mild (Child-Pugh A): No dosage adjustment necessary
- Moderate-to-severe (Child-Pugh B or C): Not recommended
Renal impairment
- CrCl ≥50 mL/min: No dosage adjustment necessary
- CrCl <50 mL/min or end-stage renal disease (ESRD) requiring hemodialysis: Not recommended because drug is a fixed-dose combination tablet and dose cannot be adjusted
Dosing Considerations
Testing prior to initiation and during treatment
- Prior to initiation of efavirenz/lamivudine/tenofovir DF, test patients for hepatitis B virus (HBV)
- Assess serum creatinine, serum phosphorus, estimated creatinine clearance, urine glucose, and urine protein in all patients as clinically appropriate
- Monitor hepatic function
Dosage Forms & Strengths
efavirenz/lamivudine/tenofovir DF (ie, tenofovir disoproxil fumarate)
tablet
- 400mg/300mg/300mg (Symfi Lo)
- 600mg/300mg/300mg (Symfi)
HIV Infection
Indicated as a complete antiretroviral (ART) regimen for the treatment of human immunodeficiency virus type 1 (HIV-1) infection in adults and children (weight dependent)
Combination consists of 2 nucleo(t)side reverse transcriptase inhibitors (NRTIs) (ie, lamivudine and tenofovir) and 1 non-nucleoside reverse transcriptase inhibitor (NNRTI) (ie, efavirenz)
Also see administration
Symfi Lo
- <35 kg: Safety and efficacy not established
- ≥35 kg: 1 tablet (efavirenz 400 mg/lamivudine 300 mg/tenofovir 300 mg) PO qHS
Symfi
- <40 kg: Safety and efficacy not established
- ≥40 kg: 1 tablet (efavirenz 600 mg/lamivudine 300 mg/tenofovir DF 300 mg) PO qHS
Dosage Modifications
Hepatic impairment
- Mild (Child-Pugh A): No dosage adjustment necessary
- Moderate-to-severe (Child-Pugh B or C): Not recommended
Renal impairment
- CrCl ≥50 mL/min: No dosage adjustment necessary
- CrCl <50 mL/min or end-stage renal disease (ESRD) requiring hemodialysis: Not recommended because drug is a fixed-dose combination tablet and dose cannot be adjusted
Dosing Considerations
Testing prior to initiation and during treatment
- Prior to initiation of efavirenz/lamivudine/tenofovir DF, test patients for hepatitis B virus (HBV)
- Assess serum creatinine, serum phosphorus, estimated creatinine clearance, urine glucose, and urine protein in all patients as clinically appropriate
- Monitor hepatic function
Clinical trials did not include sufficient number of patients aged ≥65 yr to determine if they respond differently from younger individuals
Exercise caution when administering lamivudine in elderly patients because of the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy
Interactions
Interaction Checker
No Results

Contraindicated
Serious - Use Alternative
Significant - Monitor Closely
Minor

Contraindicated (11)
- carbamazepine
carbamazepine, efavirenz. Either decreases levels of the other by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of carbamazepine with NNRTIs may result in a loss of virologic response and possible resistance to the NNRTI. A decrease in AUC is observed for both carbamazepine (27%) and efavirenz (36%) when coadministered.
- cariprazine
efavirenz will decrease the level or effect of cariprazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. CYP3A4 is responsible for the formation and elimination of cariprazine's active metabolites. The effect of CYP3A4 inducers on cariprazine exposure has not been evaluated and the net effect is unclear.
- cobimetinib
efavirenz will decrease the level or effect of cobimetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Avoid coadministration. Strong or moderate CYP3A inducers may decrease cobimetinib systemic exposure by >80% and reduce its efficacy.
- dienogest/estradiol valerate
efavirenz will decrease the level or effect of dienogest/estradiol valerate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Women should not choose estradiol valerate/dienogest as their contraceptive while using strong CYP3A4 inducers due to potential decrease in contraceptive efficacy. Estradiol valerate/dienogest should not be used for at least 28 days after discontinuation of the inducer due to possibility of decreased contraceptive efficacy.
- doravirine
efavirenz will decrease the level or effect of doravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. Coadministration of doravirine with a strong CYP3A inducer may decrease doravirine plasma concentrations and/or effects. Potential for loss of virologic response and possible resistance to doravirine.
- dronedarone
efavirenz and dronedarone both increase QTc interval. Contraindicated.
- elbasvir/grazoprevir
efavirenz will decrease the level or effect of elbasvir/grazoprevir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated. The therapeutic effect of elbasvir/grazoprevir may be reduced if coadministered with strong CYP3A inducers and is therefore contraindicated.
- elvitegravir/cobicistat/emtricitabine/tenofovir DF
lamivudine, 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.
efavirenz, elvitegravir/cobicistat/emtricitabine/tenofovir DF. Other (see comment). Contraindicated. Comment: Elvitegravir/cobicistat/emtricitabine/tenofovir is a complete regimen for HIV and should not be administered with other antiretrovirals. - emtricitabine
emtricitabine and lamivudine both increase risk of immune reconstitution syndrome. Contraindicated. Coadministration of emtricitabine containing products and lamivudine containing products should be avoided. Combination will result in therapeutic duplication.
emtricitabine, lamivudine. Other (see comment). Contraindicated. Comment: Coadministration of emtricitabine containing products and lamivudine containing products should be avoided. Combination will result in therapeutic duplication. - ergonovine
efavirenz will decrease the level or effect of ergonovine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- etravirine
efavirenz decreases levels of etravirine by increasing metabolism. Contraindicated. Mfr.'s PI recommends not combining etravirine with other NNRTIs.
Serious - Use Alternative (208)
- abemaciclib
efavirenz will decrease the level or effect of abemaciclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of abemaciclib with strong CYP3A4 inducers reduces plasma concentration of abemaciclib and its metabolites.
- abrocitinib
efavirenz will increase the level or effect of abrocitinib by decreasing metabolism. Avoid or Use Alternate Drug. Abrocitinib is a CYP2C9 and CYP2C19 substrate. Drugs that are moderate-to-strong inhibitors of both CYP2C9 and CYP2C19 increase systemic exposure of abrocitinib and its active metabolites, which may increase adverse effects.
- alfuzosin
efavirenz will decrease the level or effect of alfuzosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- alpelisib
efavirenz will decrease the level or effect of alpelisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of alpelisib (CYP3A4 substrate) with strong CYP3A4 inducers.
- amiodarone
efavirenz will decrease the level or effect of amiodarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz and amiodarone both increase QTc interval. Avoid or Use Alternate Drug. - amisulpride
efavirenz and amisulpride both increase QTc interval. Avoid or Use Alternate Drug. ECG monitoring is recommended if coadministered.
- anagrelide
efavirenz and anagrelide both increase QTc interval. Avoid or Use Alternate Drug.
- apalutamide
apalutamide will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of apalutamide, a strong CYP3A4 inducer, with drugs that are CYP3A4 substrates can result in lower exposure to these medications. Avoid or substitute another drug for these medications when possible. Evaluate for loss of therapeutic effect if medication must be coadministered. Adjust dose according to prescribing information if needed.
efavirenz will decrease the level or effect of apalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. No initial dose adjustment - apremilast
efavirenz will decrease the level or effect of apremilast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong CYP inducers results in a significant decrease of systemic exposure of apremilast, which may result in loss of efficacy
- artemether
efavirenz and artemether both increase QTc interval. Avoid or Use Alternate Drug.
- artemether/lumefantrine
efavirenz will decrease the level or effect of artemether/lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong CYP3A4 inducers can result in decreased serum concentrations and loss of antimalarial efficacy
efavirenz and artemether/lumefantrine both increase QTc interval. Avoid or Use Alternate Drug. - asenapine
efavirenz and asenapine both increase QTc interval. Avoid or Use Alternate Drug.
- asenapine transdermal
asenapine transdermal and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.
- atazanavir
efavirenz will decrease the level or effect of atazanavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- atovaquone
efavirenz decreases levels of atovaquone by unspecified interaction mechanism. Avoid or Use Alternate Drug.
- axitinib
efavirenz decreases levels of axitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Selection of concomitant medication with no or minimal CYP3A4 induction potential is recommended.
- azithromycin
efavirenz and azithromycin both increase QTc interval. Avoid or Use Alternate Drug.
- bedaquiline
efavirenz will decrease the level or effect of bedaquiline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of bedaquiline with strong CYP3A4 inducers due to potential for decreased therapeutic effect
efavirenz and bedaquiline both increase QTc interval. Avoid or Use Alternate Drug. - betibeglogene autotemcel
efavirenz, betibeglogene autotemcel. Other (see comment). Avoid or Use Alternate Drug. Comment: Do not take antiretroviral medications for at least 1 month before mobilization or expected duration for elimination of the medications, and until all cycles of apheresis are completed. Antiretroviral medications may interfere with manufacturing of apheresed cells.
lamivudine, betibeglogene autotemcel. Other (see comment). Avoid or Use Alternate Drug. Comment: Do not take antiretroviral medications for at least 1 month before mobilization or expected duration for elimination of the medications, and until all cycles of apheresis are completed. Antiretroviral medications may interfere with manufacturing of apheresed cells. - bosutinib
efavirenz decreases levels of bosutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inducers decreased bosutinib plasma concentration by ~85% .
- cabotegravir
lamivudine, 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.
- brigatinib
efavirenz will decrease the level or effect of brigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong CYP3A4 inducers may decrease brigatinib efficacy.
- bromocriptine
efavirenz increases levels of bromocriptine by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.
- buprenorphine
efavirenz and buprenorphine both increase QTc interval. Avoid or Use Alternate Drug.
- buprenorphine buccal
buprenorphine buccal and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.
- buprenorphine subdermal implant
buprenorphine subdermal implant and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.
- buprenorphine transdermal
efavirenz will decrease the level or effect of buprenorphine transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
buprenorphine transdermal and efavirenz both increase QTc interval. Avoid or Use Alternate Drug. - buprenorphine, long-acting injection
buprenorphine, long-acting injection and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.
- cabergoline
efavirenz increases levels of cabergoline by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.
- cabotegravir
efavirenz, cabotegravir. Other (see comment). Avoid or Use Alternate Drug. Comment: Cabotegravir plus rilpivirine is a complete regimen. Coadministration with other antiretroviral medications for treating HIV-1 infection is not recommended.
- cabozantinib
efavirenz will decrease the level or effect of cabozantinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of cabozantinib with strong CYP3A4 inducers. If a strong CYP3A4 inducer is required, increase cabozantinib dose by 40 mg/day (Cometriq) or by 20 mg/day (Cabometyx). Resume previous dose 2-3 days after strong CYP3A4 inducer discontinued.
- capmatinib
efavirenz will decrease the level or effect of capmatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- carvedilol
efavirenz will increase the level or effect of carvedilol by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.
- ceritinib
efavirenz decreases levels of ceritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz and ceritinib both increase QTc interval. Avoid or Use Alternate Drug.
ceritinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. - chloroquine
efavirenz and chloroquine both increase QTc interval. Avoid or Use Alternate Drug.
- chlorpromazine
efavirenz and chlorpromazine both increase QTc interval. Avoid or Use Alternate Drug.
- citalopram
efavirenz will decrease the level or effect of citalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz and citalopram both increase QTc interval. Avoid or Use Alternate Drug. - clarithromycin
efavirenz and clarithromycin both increase QTc interval. Avoid or Use Alternate Drug.
- clopidogrel
efavirenz decreases effects of clopidogrel by affecting hepatic enzyme CYP2C19 metabolism. Avoid or Use Alternate Drug. Clopidogrel efficacy may be reduced by drugs that inhibit CYP2C19. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. Clopidogrel is metabolized to this active metabolite in part by CYP2C19. .
- cobicistat
efavirenz will decrease the level or effect of cobicistat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with efavirenz may result in loss of therapeutic effect and development of resistance to cobicistat.
- copanlisib
efavirenz will decrease the level or effect of copanlisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of copanlisib with strong CYP3A4 inducers.
- crizotinib
efavirenz and crizotinib both increase QTc interval. Avoid or Use Alternate Drug.
- dabrafenib
efavirenz decreases levels of dabrafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- daridorexant
efavirenz will decrease the level or effect of daridorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- darolutamide
efavirenz will decrease the level or effect of darolutamide by Other (see comment). Avoid or Use Alternate Drug. Darolutamide is a P-gp and CYP3A4 substrate. Avoid coadminstration of darolutamide with combined P-gp and strong or moderate CYP3A4 inducers.
- darunavir
efavirenz will decrease the level or effect of darunavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with efavirenz may result in loss of therapeutic effect and development of resistance to darunavir
- deflazacort
efavirenz will decrease the level or effect of deflazacort by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of deflazacort with moderate or strong CYP3A4 inducers.
- dihydroergotamine
efavirenz will decrease the level or effect of dihydroergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- dihydroergotamine intranasal
efavirenz will decrease the level or effect of dihydroergotamine intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- disopyramide
efavirenz and disopyramide both increase QTc interval. Avoid or Use Alternate Drug.
- dofetilide
efavirenz and dofetilide both increase QTc interval. Avoid or Use Alternate Drug.
- dolutegravir
efavirenz will decrease the level or effect of dolutegravir by increasing metabolism. Avoid or Use Alternate Drug. Increase dolutegravir dose to 50 mg BID when coadministered with strong UGT1A/CYP3A inducers
- dronedarone
efavirenz will decrease the level or effect of dronedarone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- droperidol
efavirenz and droperidol both increase QTc interval. Avoid or Use Alternate Drug.
- duvelisib
efavirenz will decrease the level or effect of duvelisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with a strong CYP3A inducer decreases duvelisib area under the curve (AUC), which may reduce duvelisib efficacy.
- elacestrant
efavirenz will decrease the level or effect of elacestrant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- eletriptan
efavirenz will decrease the level or effect of eletriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- elivaldogene autotemcel
elivaldogene autotemcel, lamivudine. 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.
elivaldogene autotemcel, efavirenz. Either decreases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Patients should not take antiretroviral medications for at least 1 month before initiating medications for stem cell mobilization, for the duration of the medications? elimination, and until all cycles of apheresis are completed. - eltrombopag
efavirenz will increase the level or effect of eltrombopag by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.
- sorbitol
sorbitol will decrease the level or effect of lamivudine by Other (see comment). Avoid or Use Alternate Drug. Sorbitol-containing solution decreased systemic exposure of lamivudine oral solution in a pediatric study (ARROW trial). Results showed lower rates of virologic suppression, lower plasma lamivudine exposure, and development of viral resistance more frequently than children receiving lamivudine tablets.
- elvitegravir
efavirenz will decrease the level or effect of elvitegravir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid; coadministration with CYP3A inducers may result in decreased plasma concentrations of elvitegravir and/or a concomitantly administered protease inhibitor and lead to loss of therapeutic effect and to possible resistance
- elvitegravir/cobicistat/emtricitabine/tenofovir DF
efavirenz will decrease the level or effect of elvitegravir/cobicistat/emtricitabine/tenofovir DF by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- encorafenib
efavirenz will decrease the level or effect of encorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz and encorafenib both increase QTc interval. Avoid or Use Alternate Drug.
encorafenib and efavirenz both increase QTc interval. Avoid or Use Alternate Drug. - entrectinib
efavirenz and entrectinib both increase QTc interval. Avoid or Use Alternate Drug.
efavirenz will decrease the level or effect of entrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. - enzalutamide
efavirenz will decrease the level or effect of enzalutamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
enzalutamide will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. - erdafitinib
efavirenz will decrease the level or effect of erdafitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz will increase the level or effect of erdafitinib by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. If coadministration of a strong CYP2C9 inhibitors is unavoidable, closely monitor adverse reactions and modify dose of erdafitinib accordingly. If strong CYP2C9 inhibitor is discontinued, consider increasing erdafitinib dose in the absence of any drug-related toxicities. - ergoloid mesylates
efavirenz increases levels of ergoloid mesylates by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.
- ergotamine
efavirenz will decrease the level or effect of ergotamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
efavirenz increases levels of ergotamine by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia. - eribulin
efavirenz and eribulin both increase QTc interval. Avoid or Use Alternate Drug.
- erythromycin base
efavirenz will decrease the level or effect of erythromycin base by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
efavirenz and erythromycin base both increase QTc interval. Avoid or Use Alternate Drug. - erythromycin ethylsuccinate
efavirenz will decrease the level or effect of erythromycin ethylsuccinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
efavirenz and erythromycin ethylsuccinate both increase QTc interval. Avoid or Use Alternate Drug. - erythromycin lactobionate
efavirenz will decrease the level or effect of erythromycin lactobionate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
efavirenz and erythromycin lactobionate both increase QTc interval. Avoid or Use Alternate Drug. - erythromycin stearate
efavirenz will decrease the level or effect of erythromycin stearate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
efavirenz and erythromycin stearate both increase QTc interval. Avoid or Use Alternate Drug. - ethinylestradiol
efavirenz will decrease the level or effect of ethinylestradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. The efficacy of hormonal contraceptives may be reduced. Use of a nonhormonal contraceptive is recommended.
- ethotoin
efavirenz will increase the level or effect of ethotoin by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.
- etravirine
efavirenz will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.
- everolimus
efavirenz will decrease the level or effect of everolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- fedratinib
efavirenz will decrease the level or effect of fedratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Effect of coadministering a strong CYP3A4 inducer with fedratinib has not been studied.
- fexinidazole
efavirenz will increase the level or effect of fexinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP450 inducers may significantly increase plasma concentrations of fexinidazole?s active metabolites: fexinidazole sulfoxide (M1) and fexinidazole sulfone (M2). M2 plasma concentrations associated with increased QT prolongation risks.
fexinidazole will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Avoid or Use Alternate Drug. Coadministration may decrease plasma concentrations of CYP2B6 substrates owing to fexinidazole inducing CYP2B6.
fexinidazole and efavirenz both increase QTc interval. Avoid or Use Alternate Drug. Avoid coadministration of fexinidazole with drugs known to block potassium channels or prolong QT interval.
fexinidazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Fexinidazole inhibits CYP3A4. Coadministration may increase risk for adverse effects of CYP3A4 substrates. - finerenone
efavirenz will decrease the level or effect of finerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- fingolimod
fingolimod and efavirenz both increase QTc interval. Avoid or Use Alternate Drug.
- flecainide
efavirenz and flecainide both increase QTc interval. Avoid or Use Alternate Drug.
- foscarnet
efavirenz and foscarnet both increase QTc interval. Avoid or Use Alternate Drug.
- fosphenytoin
efavirenz will increase the level or effect of fosphenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.
- fostamatinib
efavirenz will decrease the level or effect of fostamatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- ganaxolone
efavirenz will decrease the level or effect of ganaxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ganaxolone with moderate or strong CYP3A4 inducers. If coadministration unavoidable, consider increasing ganaxolone dose; however, do not exceed maximum daily dose for weight.
- gemtuzumab
efavirenz and gemtuzumab both increase QTc interval. Avoid or Use Alternate Drug.
- glasdegib
efavirenz will decrease the level or effect of glasdegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of glasdegib with strong CYP3A inducers.
efavirenz and glasdegib both increase QTc interval. Avoid or Use Alternate Drug. If coadministration unavoidable, monitor for increased risk of QTc interval prolongation. - glecaprevir/pibrentasvir
efavirenz will decrease the level or effect of glecaprevir/pibrentasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of efavirenz (a strong CYP3A4 inducer) with glecaprevir/pibrentasvir may significantly decrease glecaprevir/pibrentasvir plasma concentrations and AUC. Potential for loss of therapeutic effect.
- hydroxychloroquine sulfate
efavirenz and hydroxychloroquine sulfate both increase QTc interval. Avoid or Use Alternate Drug.
- ibrutinib
efavirenz decreases levels of ibrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A inducers decrease ibrutinib plasma concentrations by ~10-fold.
- ibutilide
efavirenz and ibutilide both increase QTc interval. Avoid or Use Alternate Drug.
- idelalisib
efavirenz will decrease the level or effect of idelalisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration; strong CYP3A4 inducers significantly decrease idelalisib systemic exposure
idelalisib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Idelalisib is a strong CYP3A inhibitor; avoid coadministration with sensitive CYP3A substrates - iloperidone
efavirenz and iloperidone both increase QTc interval. Avoid or Use Alternate Drug.
- indinavir
efavirenz will decrease the level or effect of indinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- infigratinib
efavirenz will decrease the level or effect of infigratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- inotuzumab
efavirenz and inotuzumab both increase QTc interval. Avoid or Use Alternate Drug.
- irinotecan
efavirenz will decrease the level or effect of irinotecan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- irinotecan liposomal
efavirenz will decrease the level or effect of irinotecan liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- isoflurane
efavirenz and isoflurane both increase QTc interval. Avoid or Use Alternate Drug.
- istradefylline
efavirenz will decrease the level or effect of istradefylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of istradefylline with strong CYP3A4 inducers.
- itraconazole
itraconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Not recommended 2 weeks before and during itraconazole.
efavirenz will decrease the level or effect of itraconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Not recommended 2 weeks before and during itraconazole.
efavirenz and itraconazole both increase QTc interval. Avoid or Use Alternate Drug. - ivabradine
efavirenz will decrease the level or effect of ivabradine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ivabradine with moderate CYP3A4 inducers.
- ivacaftor
efavirenz, ivacaftor. Other (see comment). Avoid or Use Alternate Drug. Comment: Efavirenz decreases levels of ivacaftor by CYP enzyme induction; whereas, ivacaftor increases levels of efavirenz by inhibiting CYP3A4 .
- ivosidenib
efavirenz will decrease the level or effect of ivosidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of ivosidenib with strong CYP3A4 inducers decreased ivosidenib plasma concentrations.
efavirenz and ivosidenib both decrease QTc interval. Avoid or Use Alternate Drug. - ixazomib
efavirenz will decrease the level or effect of ixazomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of ixazomib with strong CYP3A inducers. Strong inducers have been shown to decrease ixazomib Cmax by 54% and AUC by 74%.
- larotrectinib
efavirenz will decrease the level or effect of larotrectinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration of larotrectinib with strong CYP3A4 inducers is unavoidable, double larotrectinib dose. Resume prior larotrectinib dose once CYP3A4 inducer discontinued for 3-5 half-lives
- lefamulin
efavirenz and lefamulin both increase QTc interval. Avoid or Use Alternate Drug.
- lemborexant
efavirenz will decrease the level or effect of lemborexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- lenacapavir
efavirenz will decrease the level or effect of lenacapavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of lenacapavir with moderate CYP3A4 inducers.
- leniolisib
efavirenz will decrease the level or effect of leniolisib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- lenvatinib
efavirenz and lenvatinib both increase QTc interval. Avoid or Use Alternate Drug.
- letermovir
efavirenz will decrease the level or effect of letermovir by Other (see comment). Avoid or Use Alternate Drug. Coadministration of letermovir with UCT1A1/3 inducers is not recommended.
- lofexidine
efavirenz and lofexidine both increase QTc interval. Avoid or Use Alternate Drug.
- lopinavir
lopinavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz and lopinavir both increase QTc interval. Avoid or Use Alternate Drug. - lorlatinib
lorlatinib will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- lovastatin
efavirenz will decrease the level or effect of lovastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- lumateperone
efavirenz will decrease the level or effect of lumateperone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- lumefantrine
efavirenz will decrease the level or effect of lumefantrine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with strong CYP3A4 inducers can result in decreased serum concentrations and loss of antimalarial efficacy
- lurbinectedin
efavirenz will decrease the level or effect of lurbinectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- macimorelin
efavirenz will decrease the level or effect of macimorelin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Potential for false positive test results if macimorelin and strong CYP3A4 inducers are coadministered. Discontinue strong CYP3A4 inducer, allowing for sufficient washout time, before testing.
efavirenz and macimorelin both increase QTc interval. Avoid or Use Alternate Drug. - macitentan
efavirenz will decrease the level or effect of macitentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministering macitentan with strong CYP3A4 inducers
- methadone
efavirenz and methadone both increase QTc interval. Avoid or Use Alternate Drug.
- methylergonovine
efavirenz increases levels of methylergonovine by decreasing metabolism. Avoid or Use Alternate Drug. Competitive inhibition of CYP3A4 might lead to vasospasm and ischemia.
- metoclopramide intranasal
efavirenz, metoclopramide intranasal. Either increases effects of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Avoid use of metoclopramide intranasal or interacting drug, depending on importance of drug to patient.
- midostaurin
efavirenz will decrease the level or effect of midostaurin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inducers may decrease midostaurin concentrations resulting in reduced efficacy.
efavirenz and midostaurin both increase QTc interval. Avoid or Use Alternate Drug. - mifepristone
mifepristone will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz will decrease the level or effect of mifepristone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz and mifepristone both increase QTc interval. Avoid or Use Alternate Drug. - mobocertinib
efavirenz will decrease the level or effect of mobocertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz and mobocertinib both increase QTc interval. Avoid or Use Alternate Drug. - moxifloxacin
efavirenz and moxifloxacin both increase QTc interval. Avoid or Use Alternate Drug.
- naloxegol
efavirenz will decrease the level or effect of naloxegol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Use of naloxegol with strong CYP3A4 inducers is not recommended
- nateglinide
efavirenz will increase the level or effect of nateglinide by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.
- nefazodone
efavirenz will decrease the level or effect of nefazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- neratinib
efavirenz will decrease the level or effect of neratinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of neratinib with strong/moderate CYP3A4 inducers.
- netupitant/palonosetron
efavirenz will decrease the level or effect of netupitant/palonosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Netupitant is mainly metabolized by CYP3A4; avoid use in patients who are chronically using a strong CYP3A4 inducer
- nevirapine
nevirapine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration not recommended as this combination has been associated with an increase in adverse reactions and no improvement in efficacy
efavirenz will decrease the level or effect of nevirapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. - nilotinib
efavirenz and nilotinib both increase QTc interval. Avoid or Use Alternate Drug.
- nisoldipine
efavirenz will decrease the level or effect of nisoldipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- norethindrone
efavirenz will decrease the level or effect of norethindrone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- olaparib
efavirenz will decrease the level or effect of olaparib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration with moderate CYP3A inducers cannot be avoided, be aware of a potential for decreased efficacy of olaparib
- olopatadine intranasal
efavirenz and olopatadine intranasal both increase sedation. Avoid or Use Alternate Drug. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
- olutasidenib
efavirenz will decrease the level or effect of olutasidenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong or moderate CYP3A inducers decrease olutasidenib (a CYP3A4 substrate) plasma concentrations and efficacy.
- omaveloxolone
efavirenz will decrease the level or effect of omaveloxolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- ondansetron
efavirenz and ondansetron both increase QTc interval. Avoid or Use Alternate Drug.
- osimertinib
efavirenz will decrease the level or effect of osimertinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of osimertinib with strong CYP3A inducers.
efavirenz and osimertinib both increase QTc interval. Avoid or Use Alternate Drug. - oxaliplatin
efavirenz and oxaliplatin both increase QTc interval. Avoid or Use Alternate Drug.
- ozanimod
efavirenz and ozanimod both increase QTc interval. Avoid or Use Alternate Drug.
- palovarotene
efavirenz will decrease the level or effect of palovarotene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- panobinostat
efavirenz and panobinostat both increase QTc interval. Avoid or Use Alternate Drug.
- parecoxib
efavirenz will increase the level or effect of parecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug.
- pazopanib
efavirenz and pazopanib both increase QTc interval. Avoid or Use Alternate Drug.
- pemigatinib
efavirenz will decrease the level or effect of pemigatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- pentamidine
efavirenz and pentamidine both increase QTc interval. Avoid or Use Alternate Drug.
- perampanel
efavirenz will decrease the level or effect of perampanel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- pexidartinib
efavirenz will decrease the level or effect of pexidartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz and pexidartinib both increase Other (see comment). Avoid or Use Alternate Drug. Pexidartinib can cause hepatotoxicity. Avoid coadministration of pexidartinib with other products know to cause hepatoxicity. - pimavanserin
efavirenz and pimavanserin both increase QTc interval. Avoid or Use Alternate Drug.
- pimozide
efavirenz and pimozide both increase QTc interval. Contraindicated.
- pirtobrutinib
efavirenz will decrease the level or effect of pirtobrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If coadministration unavoidable, increase pirtobrutinib dose to 300 mg qDay (if dose is 200 mg qDay) or increase pirtobrutinib dose by 50 mg (if current pirtobrutinib dose is 50 mg or 100 mg qDay).
- pitolisant
efavirenz and pitolisant both increase QTc interval. Avoid or Use Alternate Drug.
- pomalidomide
efavirenz decreases levels of pomalidomide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- ponesimod
efavirenz and ponesimod both increase QTc interval. Avoid or Use Alternate Drug.
- pralsetinib
efavirenz will decrease the level or effect of pralsetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid, double current pralsetinib dose starting on Day 7 of coadministration with strong CYP3A inducer. After inducer has been discontinued for at least 14 days, resume previous pralsetinib dose.
- pretomanid
efavirenz will decrease the level or effect of pretomanid by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. CYP3A4 substrate. Avoid coadministration of strong or moderate CYP3A4 inducers.
efavirenz, pretomanid. Either increases toxicity of the other by Other (see comment). Avoid or Use Alternate Drug. Comment: Pretomanid regimen associated with hepatotoxicity. Avoid alcohol and hepatotoxic agents, including herbal supplements and drugs other than bedaquiline and linezolid. - procainamide
efavirenz and procainamide both increase QTc interval. Avoid or Use Alternate Drug.
- propafenone
efavirenz and propafenone both increase QTc interval. Avoid or Use Alternate Drug.
- quetiapine
efavirenz and quetiapine both increase QTc interval. Avoid or Use Alternate Drug.
- quinidine
efavirenz and quinidine both increase QTc interval. Avoid or Use Alternate Drug.
- quinine
efavirenz and quinine both increase QTc interval. Avoid or Use Alternate Drug.
- quizartinib
efavirenz will decrease the level or effect of quizartinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- ranolazine
efavirenz will decrease the level or effect of ranolazine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- regorafenib
efavirenz will decrease the level or effect of regorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inducers decrease regorafenib levels and increase exposure of the active metabolite M-5
- ribociclib
ribociclib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz and ribociclib both increase QTc interval. Avoid or Use Alternate Drug. - rifabutin
efavirenz will decrease the level or effect of rifabutin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- rilpivirine
efavirenz and rilpivirine both increase QTc interval. Avoid or Use Alternate Drug.
- rimegepant
efavirenz will decrease the level or effect of rimegepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- ripretinib
efavirenz will decrease the level or effect of ripretinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration with a strong CYP3A inhibitor will decrease systemic exposure to ripretinib and its active metabolite (DP-5439), which may decrease risk of adverse reactions.
- risperidone
efavirenz and risperidone both increase QTc interval. Avoid or Use Alternate Drug.
- rolapitant
efavirenz will decrease the level or effect of rolapitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Long-term coadministration of strong CYP3A4 inducers with rolapitant may significantly decrease rolapitant efficacy.
- ropeginterferon alfa 2b
ropeginterferon alfa 2b and efavirenz both increase Other (see comment). Avoid or Use Alternate Drug. Narcotics, hypnotics or sedatives can produce additive neuropsychiatric side effects. Avoid use and monitor patients receiving the combination for effects of excessive CNS toxicity.
- saquinavir
saquinavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz and saquinavir both increase QTc interval. Avoid or Use Alternate Drug. - selpercatinib
efavirenz will decrease the level or effect of selpercatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz and selpercatinib both increase QTc interval. Avoid or Use Alternate Drug. - selumetinib
efavirenz will decrease the level or effect of selumetinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- sevoflurane
efavirenz and sevoflurane both increase QTc interval. Avoid or Use Alternate Drug.
- silodosin
efavirenz will decrease the level or effect of silodosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- siponimod
efavirenz will increase the level or effect of siponimod by affecting hepatic enzyme CYP2C9/10 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with drugs that cause moderate CYP2C9 AND a moderate or strong CYP3A4 inhibition is not recommended. Caution if siponimod coadministered with moderate CYP2C9 inhibitors alone.
efavirenz will decrease the level or effect of siponimod by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Coadministration of siponimod with a drug that causes moderate CYP2C9 plus a moderate or strong CYP3A4 inducer is not recommended. Coadministration with moderate or strong CYP3A4 inducers alone is not recommended for patients with CYP2C9*1/*3 and*2/*3 genotype.
efavirenz and siponimod both increase QTc interval. Avoid or Use Alternate Drug. - sirolimus
efavirenz will decrease the level or effect of sirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- sofosbuvir/velpatasvir
efavirenz will decrease the level or effect of sofosbuvir/velpatasvir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Velpatasvir is a substrate of CYP2B6, CYP2C8, and CYP3A4. Drugs that are moderate-to-potent inducers of CYP2B6, CYP2C8, or CYP3A4 may significantly decrease velpatasvir plasma concentrations, leading to potentially reduced therapeutic effect.
- sonidegib
efavirenz will decrease the level or effect of sonidegib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid coadministration of sonidegib with strong or moderate CYP3A4 inducers.
- sorafenib
efavirenz will decrease the level or effect of sorafenib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz and sorafenib both increase QTc interval. Avoid or Use Alternate Drug. - sotalol
efavirenz and sotalol both increase QTc interval. Avoid or Use Alternate Drug.
- sotorasib
efavirenz will decrease the level or effect of sotorasib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- St John's Wort
St John's Wort will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- stiripentol
efavirenz will decrease the level or effect of stiripentol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. If unable to avoid coadministration of stiripentol with strong CYP3A4 inducers, increase stiripentol dose.
- sunitinib
efavirenz and sunitinib both increase QTc interval. Avoid or Use Alternate Drug.
- suvorexant
efavirenz will decrease the level or effect of suvorexant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Strong CYP3A4 inducers may decrease suvorexant efficacy; if increased suvorexant dose required, do not exceed 20 mg/day
- tacrolimus
efavirenz will decrease the level or effect of tacrolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- tafenoquine
tafenoquine will increase the level or effect of lamivudine by Other (see comment). Avoid or Use Alternate Drug. Tafenoquine inhibits organic cation transporter-2 (OCT2) and multidrug and toxin extrusion (MATE) transporters in vitro. Avoid coadministration with OCT2 or MATE substrates. If coadministration cannot be avoided, monitor for substrate-related toxicities and consider dosage reduction if needed based on product labeling of the coadministered drug.
- tazemetostat
efavirenz will decrease the level or effect of tazemetostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- tetrabenazine
efavirenz and tetrabenazine both increase QTc interval. Avoid or Use Alternate Drug.
- tezacaftor
efavirenz will decrease the level or effect of tezacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- thiothixene
efavirenz and thiothixene both increase QTc interval. Contraindicated.
- tivozanib
efavirenz will decrease the level or effect of tivozanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- tolvaptan
efavirenz will decrease the level or effect of tolvaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Contraindicated.
- toremifene
efavirenz and toremifene both increase QTc interval. Avoid or Use Alternate Drug.
- trabectedin
efavirenz will decrease the level or effect of trabectedin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
- trazodone
efavirenz and trazodone both increase QTc interval. Avoid or Use Alternate Drug.
- triazolam
efavirenz increases levels of triazolam by decreasing metabolism. Contraindicated.
- trilaciclib
trilaciclib will decrease the level or effect of lamivudine by Other (see comment). Avoid or Use Alternate Drug. Avoid coadministration of trilaciclib (OCT2, MATE1, and MATE-2K inhibitor) with substrates where minimal increased concentration in kidney or blood may lead to serious or life-threatening toxicities.
- tucatinib
efavirenz will decrease the level or effect of tucatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug.
efavirenz will increase the level or effect of tucatinib by Other (see comment). Avoid or Use Alternate Drug. Coadministration of tucatinib (a CYP2C8 substrate) with a strong or moderate CYP2C8 inhibitors increases tucatinib plasma concentrations and risk of toxicities.
tucatinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Avoid or Use Alternate Drug. Avoid concomitant use of tucatinib with CYP3A substrates, where minimal concentration changes may lead to serious or life-threatening toxicities. If unavoidable, reduce CYP3A substrate dose according to product labeling.
Monitor Closely (353)
- abacavir
abacavir and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
abacavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor. - abiraterone
efavirenz decreases levels of abiraterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Avoid coadministration of abiraterone with strong CYP3A4 inducers; if a strong CYP3A4 inducer must be used, increase abiraterone dosage frequency from once daily to twice daily.
- atazanavir
atazanavir and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
- acalabrutinib
efavirenz will decrease the level or effect of acalabrutinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- acrivastine
acrivastine and efavirenz both increase sedation. Use Caution/Monitor.
- albuterol
efavirenz and albuterol both increase QTc interval. Use Caution/Monitor.
- alfentanil
efavirenz will decrease the level or effect of alfentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- alfuzosin
efavirenz and alfuzosin both increase QTc interval. Use Caution/Monitor.
- almotriptan
efavirenz will decrease the level or effect of almotriptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- alosetron
efavirenz will increase the level or effect of alosetron by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- alprazolam
efavirenz will decrease the level or effect of alprazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- amisulpride
amisulpride and efavirenz both increase sedation. Use Caution/Monitor.
- amitriptyline
efavirenz will increase the level or effect of amitriptyline by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
efavirenz will decrease the level or effect of amitriptyline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and amitriptyline both increase QTc interval. Use Caution/Monitor. - amlodipine
efavirenz will decrease the level or effect of amlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- apixaban
efavirenz will decrease the level or effect of apixaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- apomorphine
efavirenz and apomorphine both increase QTc interval. Use Caution/Monitor.
- aprepitant
efavirenz will decrease the level or effect of aprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- arformoterol
efavirenz and arformoterol both increase QTc interval. Use Caution/Monitor.
- aripiprazole
efavirenz will decrease the level or effect of aripiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and aripiprazole both increase QTc interval. Use Caution/Monitor. - arsenic trioxide
efavirenz and arsenic trioxide both increase QTc interval. Use Caution/Monitor.
- asenapine
asenapine and efavirenz both increase sedation. Use Caution/Monitor.
- asenapine transdermal
asenapine transdermal and efavirenz both increase sedation. Use Caution/Monitor.
- atazanavir
atazanavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
- atogepant
efavirenz will decrease the level or effect of atogepant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Recommended atogepant dosage with concomitant use of strong or moderate CYP3A4 inducers is 30 mg or 60 mg qDay.
- atomoxetine
efavirenz and atomoxetine both increase QTc interval. Use Caution/Monitor.
- atorvastatin
efavirenz will decrease the level or effect of atorvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- avanafil
efavirenz will decrease the level or effect of avanafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibitors may reduce avanafil clearance increasing systemic exposure to avanafil; increased levels may result in increased associated adverse events; the maximum recommended dose of STENDRA is 50 mg, not to exceed once every 24 hours for patients taking concomitant moderate CYP3A4 inhibitors
- avapritinib
efavirenz will decrease the level or effect of avapritinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
avapritinib and efavirenz both increase sedation. Use Caution/Monitor. - bazedoxifene/conjugated estrogens
efavirenz will decrease the level or effect of bazedoxifene/conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- belumosudil
efavirenz will increase the level or effect of belumosudil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase belumosudil dosage to 200 mg PO BID when coadministered with strong CYP3A inducers.
- belzutifan
belzutifan will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. If unable to avoid coadministration of belzutifan with sensitive CYP3A4 substrates, consider increasing the sensitive CYP3A4 substrate dose in accordance with its prescribing information.
- benzhydrocodone/acetaminophen
efavirenz will decrease the level or effect of benzhydrocodone/acetaminophen by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Caution when discontinuing CYP3A4 inducers that are coadministered with benzhydrocodone (prodrug of hydrocodone); plasma concentrations of hydrocodone may increase and can result in potentially fatal respiratory depression.
benzhydrocodone/acetaminophen and efavirenz both increase sedation. Use Caution/Monitor. - bortezomib
efavirenz will decrease the level or effect of bortezomib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- bosentan
efavirenz will increase the level or effect of bosentan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- brentuximab vedotin
efavirenz will decrease the level or effect of brentuximab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- brexanolone
brexanolone, efavirenz. Either increases toxicity of the other by sedation. Use Caution/Monitor.
- brexpiprazole
efavirenz will decrease the level or effect of brexpiprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Double brexpiprazole dose over 1-2 weeks if administered with a strong CYP3A4 inducer.
brexpiprazole and efavirenz both increase sedation. Use Caution/Monitor. - brimonidine
brimonidine and efavirenz both increase sedation. Use Caution/Monitor.
- brivaracetam
brivaracetam and efavirenz both increase sedation. Use Caution/Monitor.
- buprenorphine
efavirenz will decrease the level or effect of buprenorphine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- buprenorphine buccal
efavirenz will decrease the level or effect of buprenorphine buccal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- buprenorphine subdermal implant
efavirenz will decrease the level or effect of buprenorphine subdermal implant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor patients already on buprenorphine subdermal implant who require newly-initiated treatment with CYP3A4 inducer for signs and symptoms of withdrawal. If the dose of the concomitant CYP3A4 inducer cannot be reduced or discontinued, implant removal may be necessary and the patient should then be treated with a buprenorphine dosage form that permits dose adjustments. If a CYP3A4 inducer is discontinued in a patient who has been stabilized on buprenorphine, monitor the patient for overmedication.
buprenorphine subdermal implant and efavirenz both increase sedation. Use Caution/Monitor. - buprenorphine transdermal
buprenorphine transdermal and efavirenz both increase sedation. Use Caution/Monitor.
- buprenorphine, long-acting injection
efavirenz will decrease the level or effect of buprenorphine, long-acting injection by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Patients who transfer to buprenorphine long-acting injection from transmucosal buprenorphine coadministered with CYP3A4 inducers should be monitored to ensure buprenorphine plasma levels are adequate. If the buprenorphine dose is inadequate and the CYP3A4 inducer cannot be reduced or discontinued, transition the patient back to a buprenorphine formulation that permits dose adjustments.
buprenorphine, long-acting injection and efavirenz both increase sedation. Use Caution/Monitor. - bupropion
efavirenz will decrease the level or effect of bupropion by increasing metabolism. Use Caution/Monitor. Coadministration with hepatic inducers reduced bupropion AUC and Cmax; hydroxybupropion (active metabolite) Cmax was increased
- buspirone
efavirenz will decrease the level or effect of buspirone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- cabazitaxel
efavirenz will increase the level or effect of cabazitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution should be exercised with concomitant use of moderate CYP3A4 inhibitors.
- cabozantinib
lamivudine will increase the level or effect of cabozantinib by Other (see comment). Use Caution/Monitor. MRP2 inhibitors increase cabozantinib toxicity
- calcifediol
efavirenz, calcifediol. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Drugs that stimulate microsomal hydroxylation reduce the half-life of calcifediol.
- calcitriol
efavirenz will decrease the level or effect of calcitriol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- cannabidiol
efavirenz will increase the level or effect of cannabidiol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider reducing the cannabidiol dose when coadministered with a moderate CYP2C19 inhibitor.
efavirenz will decrease the level or effect of cannabidiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Consider an increase in cannabidiol dosage (based on clinical response and tolerability) when coadministered with a strong CYP3A4 inducer.
cannabidiol, efavirenz. affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Owing to the potential for both CYP2B6 induction and inhibition with the coadministration of CYP2B6 substrates and cannabidiol, consider reducing dosage adjustment of CYP2B6 substrates as clinically appropriate. - carbamazepine
carbamazepine will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
- celecoxib
efavirenz will increase the level or effect of celecoxib by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- cenobamate
cenobamate will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP2B6 substrate, as needed, when coadministered with cenobamate.
cenobamate will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase dose of CYP3A4 substrate, as needed, when coadministered with cenobamate.
cenobamate, efavirenz. Either increases levels of the other by sedation. Use Caution/Monitor. - chlordiazepoxide
efavirenz will decrease the level or effect of chlordiazepoxide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- chloroquine
efavirenz will decrease the level or effect of chloroquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- chlorpheniramine
efavirenz will decrease the level or effect of chlorpheniramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- cilostazol
efavirenz will decrease the level or effect of cilostazol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz increases toxicity of cilostazol by affecting hepatic enzyme CYP2C19 metabolism. Modify Therapy/Monitor Closely. Consider decreasing cilostazol dose; moderate CYP2C19 inhibitors may increase serum levels of 3,4-dehydrocilostazol (active metabolite). - cinacalcet
efavirenz will decrease the level or effect of cinacalcet by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ciprofloxacin
efavirenz and ciprofloxacin both increase QTc interval. Use Caution/Monitor.
- cisapride
efavirenz and cisapride both increase QTc interval. Use Caution/Monitor.
- clarithromycin
clarithromycin will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- clobazam
efavirenz will increase the level or effect of clobazam by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Dosage adjustment may be required; CYP2C19 inhibitors may result in increased exposure to N-desmethylclobazam (active metabolite).
efavirenz, clobazam. Other (see comment). Use Caution/Monitor. Comment: Concomitant administration can increase the potential for CNS effects (e.g., increased sedation or respiratory depression). - clomipramine
efavirenz and clomipramine both increase QTc interval. Use Caution/Monitor.
- clonazepam
efavirenz will decrease the level or effect of clonazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- clopidogrel
efavirenz decreases effects of clopidogrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Clopidogrel efficacy may be reduced by drugs that inhibit CYP3A4. Inhibition of platelet aggregation by clopidogrel is entirely due to an active metabolite. Clopidogrel is metabolized to this active metabolite in part by CYP3A4. .
- clorazepate
efavirenz will decrease the level or effect of clorazepate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- clozapine
efavirenz will decrease the level or effect of clozapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and clozapine both increase QTc interval. Use Caution/Monitor. - cobicistat
cobicistat will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- conivaptan
efavirenz will decrease the level or effect of conivaptan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- conjugated estrogens
efavirenz will decrease the level or effect of conjugated estrogens by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- conjugated estrogens, vaginal
efavirenz will decrease the level or effect of conjugated estrogens, vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- cortisone
efavirenz will decrease the level or effect of cortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- crizotinib
efavirenz increases levels of crizotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Caution should be exercised with concomitant use of moderate CYP3A inhibitors. .
- crofelemer
crofelemer increases levels of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Crofelemer has the potential to inhibit CYP3A4 at concentrations expected in the gut; unlikely to inhibit systemically because minimally absorbed.
- cyclophosphamide
efavirenz will decrease the level or effect of cyclophosphamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- cyclosporine
efavirenz will decrease the level or effect of cyclosporine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Closely monitor cyclosporine concentrations when starting, stopping, or adjusting dose of concurrent efavirez, especially within first 2 weeks.
- dabrafenib
dabrafenib will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- dantrolene
efavirenz will decrease the level or effect of dantrolene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- daprodustat
efavirenz will increase the level or effect of daprodustat by Other (see comment). Modify Therapy/Monitor Closely. Moderate CYP2C8 inhibitors increase daprodustat exposure. If coadministered with moderate CYP2C8 inhibitors, reduce daprodustat starting dose by half (except if starting dose is already 1 mg). Monitor hemoglobin and adjust daprodustat dose when initiating or stopping therapy with moderate CYP2C8 inhibitors during treatment
- dapsone
efavirenz will decrease the level or effect of dapsone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- daridorexant
efavirenz and daridorexant both increase sedation. Modify Therapy/Monitor Closely. Coadministration increases risk of CNS depression, which can lead to additive impairment of psychomotor performance and cause daytime impairment.
- darifenacin
efavirenz will decrease the level or effect of darifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- darunavir
darunavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
- dasatinib
efavirenz will decrease the level or effect of dasatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and dasatinib both increase QTc interval. Use Caution/Monitor. - deferasirox
deferasirox will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- degarelix
efavirenz and degarelix both increase QTc interval. Use Caution/Monitor.
- desipramine
efavirenz and desipramine both increase QTc interval. Use Caution/Monitor.
- deutetrabenazine
efavirenz and deutetrabenazine both increase QTc interval. Use Caution/Monitor. At the maximum recommended dose, deutetrabenazine does not prolong QT interval to a clinically relevant extent. Certain circumstances may increase risk of torsade de pointes and/or sudden death in association with drugs that prolong the QTc interval (eg, bradycardia, hypokalemia or hypomagnesemia, coadministration with other drugs that prolong QTc interval, presence of congenital QT prolongation).
- dexamethasone
efavirenz will decrease the level or effect of dexamethasone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- diazepam
efavirenz will decrease the level or effect of diazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- diazepam intranasal
efavirenz will decrease the level or effect of diazepam intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong or moderate CYP3A4 inducers may increase rate of diazepam elimination; therefore, efficacy of diazepam may be decreased.
efavirenz will increase the level or effect of diazepam intranasal by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor. Strong or moderate CYP2C19 inhibitors may decrease rate of diazepam elimination, thereby increasing adverse reactions to diazepam. - diclofenac
efavirenz will increase the level or effect of diclofenac by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- didanosine
didanosine, efavirenz. Either increases effects of the other by pharmacodynamic synergism. Use Caution/Monitor. Concomitant administration increases risk of liver toxicity.
- difelikefalin
difelikefalin and efavirenz both increase sedation. Use Caution/Monitor.
- diltiazem
efavirenz will decrease the level or effect of diltiazem by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- docetaxel
efavirenz will decrease the level or effect of docetaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- dolasetron
efavirenz and dolasetron both increase QTc interval. Use Caution/Monitor.
- donepezil
efavirenz will decrease the level or effect of donepezil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- doxepin
efavirenz and doxepin both increase QTc interval. Use Caution/Monitor.
- doxorubicin
efavirenz will decrease the level or effect of doxorubicin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- doxorubicin liposomal
efavirenz will decrease the level or effect of doxorubicin liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- dronabinol
efavirenz will increase the level or effect of dronabinol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dronabinol is a CYP3A4 substrate.
- dronedarone
dronedarone will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. May decrease dronedarone levels.
- efavirenz
efavirenz and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
- elagolix
efavirenz will decrease the level or effect of elagolix by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
elagolix will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Elagolix is a weak-to-moderate CYP3A4 inducer. Monitor CYP3A substrates if coadministered. Consider increasing CYP3A substrate dose if needed. - eliglustat
efavirenz will decrease the level or effect of eliglustat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A inducers significantly decreases eliglustat exposure; coadministration not recommended
efavirenz and eliglustat both increase QTc interval. Use Caution/Monitor. - emtricitabine
efavirenz and emtricitabine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
- encorafenib
encorafenib, efavirenz. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Encorafenib both inhibits and induces CYP3A4 at clinically relevant plasma concentrations. Coadministration of encorafenib with sensitive CYP3A4 substrates may result in increased toxicity or decreased efficacy of these agents.
- enfuvirtide
efavirenz and enfuvirtide both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
enfuvirtide and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor. - erdafitinib
lamivudine increases levels of erdafitinib by decreasing renal clearance. Modify Therapy/Monitor Closely. Consider alternatives that are not OCT2 substrates or consider reducing the dose of OCT2 substrates based on tolerability.
- erlotinib
efavirenz will decrease the level or effect of erlotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- erythromycin base
erythromycin base will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- erythromycin ethylsuccinate
erythromycin ethylsuccinate will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- erythromycin lactobionate
erythromycin lactobionate will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- erythromycin stearate
erythromycin stearate will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- escitalopram
efavirenz will increase the level or effect of escitalopram by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
efavirenz will decrease the level or effect of escitalopram by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and escitalopram both increase QTc interval. Use Caution/Monitor. - esketamine intranasal
esketamine intranasal, efavirenz. Either increases toxicity of the other by sedation. Modify Therapy/Monitor Closely.
- eslicarbazepine acetate
eslicarbazepine acetate will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- esomeprazole
efavirenz will decrease the level or effect of esomeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- estradiol
efavirenz will decrease the level or effect of estradiol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- estradiol vaginal
efavirenz will decrease the level or effect of estradiol vaginal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- estrogens conjugated synthetic
efavirenz will decrease the level or effect of estrogens conjugated synthetic by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- estrogens esterified
efavirenz will decrease the level or effect of estrogens esterified by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- estropipate
efavirenz will decrease the level or effect of estropipate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- eszopiclone
efavirenz will decrease the level or effect of eszopiclone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ethosuximide
efavirenz will decrease the level or effect of ethosuximide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- etonogestrel
efavirenz will decrease the level or effect of etonogestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- etoposide
efavirenz will decrease the level or effect of etoposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- etravirine
efavirenz will increase the level or effect of etravirine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
efavirenz will decrease the level or effect of etravirine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - exemestane
efavirenz will decrease the level or effect of exemestane by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. For patients receiving exemestane with a potent CYP3A4 inducer the recommended dose of exemestane is 50 mg daily after a meal.
- fedratinib
fedratinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Adjust dose of drugs that are CYP3A4 substrates as necessary.
- felbamate
efavirenz will decrease the level or effect of felbamate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- felodipine
efavirenz will decrease the level or effect of felodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- fentanyl
efavirenz will decrease the level or effect of fentanyl by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead to a decrease in fentanyl plasma concentrations, lack of efficacy or, possibly, development of a withdrawal syndrome in a patient who has developed physical dependence to fentanyl. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase which could increase or prolong both the therapeutic and adverse effects.
- fentanyl intranasal
efavirenz will decrease the level or effect of fentanyl intranasal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead to a decrease in fentanyl plasma concentrations, lack of efficacy or, possibly, development of a withdrawal syndrome in a patient who has developed physical dependence to fentanyl. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase which could increase or prolong both the therapeutic and adverse effects.
- fentanyl transdermal
efavirenz will decrease the level or effect of fentanyl transdermal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead to a decrease in fentanyl plasma concentrations, lack of efficacy or, possibly, development of a withdrawal syndrome in a patient who has developed physical dependence to fentanyl. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase which could increase or prolong both the therapeutic and adverse effects.
- fentanyl transmucosal
efavirenz will decrease the level or effect of fentanyl transmucosal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of fentanyl with CYP3A4 inducers could lead to a decrease in fentanyl plasma concentrations, lack of efficacy or, possibly, development of a withdrawal syndrome in a patient who has developed physical dependence to fentanyl. After stopping a CYP3A4 inducer, as the effects of the inducer decline, the fentanyl plasma concentration will increase which could increase or prolong both the therapeutic and adverse effects.
- fesoterodine
efavirenz will decrease the level or effect of fesoterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- flibanserin
efavirenz will decrease the level or effect of flibanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inducers substantially decrease flibanserin systemic exposure.
- fluconazole
efavirenz and fluconazole both increase QTc interval. Use Caution/Monitor.
- fludrocortisone
efavirenz will decrease the level or effect of fludrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- fluoxetine
efavirenz and fluoxetine both increase QTc interval. Use Caution/Monitor.
- fluphenazine
efavirenz and fluphenazine both increase QTc interval. Use Caution/Monitor.
- flurazepam
efavirenz will decrease the level or effect of flurazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- flurbiprofen
efavirenz will increase the level or effect of flurbiprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- fluvastatin
efavirenz will increase the level or effect of fluvastatin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- fluvoxamine
fluvoxamine will increase the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
efavirenz and fluvoxamine both increase QTc interval. Use Caution/Monitor. - formoterol
efavirenz and formoterol both increase QTc interval. Use Caution/Monitor.
- fosamprenavir
fosamprenavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
efavirenz will decrease the level or effect of fosamprenavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
fosamprenavir and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor. - fosaprepitant
efavirenz will decrease the level or effect of fosaprepitant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ganciclovir
ganciclovir, lamivudine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Increased risk of hematologic toxicity.
- fostemsavir
efavirenz and fostemsavir both increase QTc interval. Use Caution/Monitor. QTc prolongation reported with higher than recommended doses of fostemsavir.
- ganaxolone
efavirenz and ganaxolone both increase sedation. Use Caution/Monitor.
- gefitinib
efavirenz will decrease the level or effect of gefitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Increase gefitinib to 500 mg daily if coadministered with a strong CYP3A4 inducer. Resume gefitinib dose at 250 mg/day 7 days after discontinuing the strong inducer.
- gemifloxacin
efavirenz and gemifloxacin both increase QTc interval. Use Caution/Monitor.
- gilteritinib
efavirenz and gilteritinib both increase QTc interval. Use Caution/Monitor.
- goserelin
efavirenz and goserelin both increase QTc interval. Use Caution/Monitor.
- granisetron
efavirenz and granisetron both increase QTc interval. Use Caution/Monitor.
- guanfacine
efavirenz will decrease the level or effect of guanfacine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Strong or moderate CYP3A4 inducers significantly reduce guanfacine plasma concentrations and elimination half-life. If coadministered, more frequent dosing of the IR product may be required to achieve or maintain the desired hypotensive response. For patients with ADHD, FDA-approved labeling for ER guanfacine recommends that, if coadministered, doubling the recommended dose of guanfacine should be considered.
- haloperidol
efavirenz will decrease the level or effect of haloperidol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and haloperidol both increase QTc interval. Use Caution/Monitor. - histrelin
efavirenz and histrelin both increase QTc interval. Use Caution/Monitor.
- hydrocodone
efavirenz will decrease the level or effect of hydrocodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Caution when discontinuing CYP3A4 inducers that are coadministered with hydrocodone; plasma concentrations of hydrocodone may increase and can result in potentially fatal respiratory depression
- hydrocortisone
efavirenz will decrease the level or effect of hydrocortisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- hydroxyprogesterone caproate (DSC)
efavirenz will decrease the level or effect of hydroxyprogesterone caproate (DSC) by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- hydroxyzine
efavirenz and hydroxyzine both increase QTc interval. Use Caution/Monitor.
- ibuprofen
efavirenz will increase the level or effect of ibuprofen by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- ibuprofen IV
efavirenz will increase the level or effect of ibuprofen IV by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- ifosfamide
efavirenz increases toxicity of ifosfamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inducers may increase the metabolism of ifosfamide to its active alkylating metabolites. CYP3A4 inducers may increase the formation of the neurotoxic/nephrotoxic ifosfamide metabolite, chloroacetaldehyde. Closely monitor patients taking ifosfamide with CYP3A4 inducers for toxicities and consider dose adjustment.
efavirenz increases effects of ifosfamide by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Coadministration of ifosfamide with CYP2B6 inducers may increase metabolism of ifosfamide to its metabolite. Monitor for increased effects/toxicities if combined with CYP2B6 inducers. - iloperidone
efavirenz will decrease the level or effect of iloperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
iloperidone increases levels of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Iloperidone is a time-dependent CYP3A inhibitor and may lead to increased plasma levels of drugs predominantly eliminated by CYP3A4. - imipramine
efavirenz will increase the level or effect of imipramine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
efavirenz and imipramine both increase QTc interval. Use Caution/Monitor. - indacaterol, inhaled
efavirenz and indacaterol, inhaled both increase QTc interval. Use Caution/Monitor.
- indinavir
indinavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
indinavir and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor. - interferon alfa 2b
interferon alfa 2b, lamivudine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of liver decompensation.
- isoniazid
isoniazid will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- isosorbide dinitrate
efavirenz will decrease the level or effect of isosorbide dinitrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- isosorbide mononitrate
efavirenz will decrease the level or effect of isosorbide mononitrate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- isradipine
efavirenz will decrease the level or effect of isradipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and isradipine both increase QTc interval. Use Caution/Monitor. - istradefylline
istradefylline will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Istradefylline 40 mg/day increased peak levels and AUC of CYP3A4 substrates in clinical trials. This effect was not observed with istradefylline 20 mg/day. Consider dose reduction of sensitive CYP3A4 substrates.
- ivacaftor
efavirenz will decrease the level or effect of ivacaftor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ivosidenib
ivosidenib will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ixabepilone
efavirenz will decrease the level or effect of ixabepilone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ketamine
efavirenz will increase the level or effect of ketamine by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
efavirenz will decrease the level or effect of ketamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - ketoconazole
ketoconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- lamivudine
efavirenz and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
- lansoprazole
efavirenz will decrease the level or effect of lansoprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- lapatinib
efavirenz will decrease the level or effect of lapatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and lapatinib both increase QTc interval. Use Caution/Monitor. - lasmiditan
lasmiditan, efavirenz. Either increases effects of the other by sedation. Use Caution/Monitor. Coadministration of lasmiditan and other CNS depressant drugs, including alcohol have not been evaluated in clinical studies. Lasmiditan may cause sedation, as well as other cognitive and/or neuropsychiatric adverse reactions.
- lemborexant
lemborexant will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Monitor CYP2B6 substrate for adequate clinical response. Consider increasing the CYP2B6 substrate dose according to specific prescribing recommendations.
- letermovir
letermovir increases levels of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- leuprolide
efavirenz and leuprolide both increase QTc interval. Use Caution/Monitor.
- levalbuterol
efavirenz and levalbuterol both increase QTc interval. Use Caution/Monitor.
- levamlodipine
efavirenz will decrease the level or effect of levamlodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. No information is available on the quantitative effects of CYP3A4 inducers on amlodipine. Closely monitor blood pressure when amlodipine is coadministered with CYP3A4 inducers.
- levofloxacin
efavirenz and levofloxacin both increase QTc interval. Use Caution/Monitor.
- levoketoconazole
levoketoconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- levonorgestrel intrauterine
efavirenz decreases levels of levonorgestrel intrauterine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- levonorgestrel oral
efavirenz decreases levels of levonorgestrel oral by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- levonorgestrel oral/ethinylestradiol/ferrous bisglycinate
efavirenz will decrease the level or effect of levonorgestrel oral/ethinylestradiol/ferrous bisglycinate by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. The efficacy of hormonal contraceptives may be reduced. Use an alternative method of contraception or a backup method when enzyme inducers are used with combined hormonal contraceptives (CHCs), and continue backup contraception for 28 days after discontinuing enzyme inducer to ensure contraceptive reliability.
- linagliptin
efavirenz will decrease the level or effect of linagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Use of alternative treatments is strongly recommended when linagliptin is to be administered with a CYP3A4 inducer.
efavirenz will decrease the level or effect of linagliptin by Other (see comment). Use Caution/Monitor. Reports of hyperglycemia due to insulin resistance with protease inhibitors. - lithium
efavirenz and lithium both increase QTc interval. Use Caution/Monitor.
- loperamide
efavirenz and loperamide both increase QTc interval. Use Caution/Monitor.
- lopinavir
efavirenz will decrease the level or effect of lopinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- loratadine
efavirenz will decrease the level or effect of loratadine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- losartan
efavirenz will increase the level or effect of losartan by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.
efavirenz will decrease the level or effect of losartan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - lumacaftor/ivacaftor
lumacaftor/ivacaftor, efavirenz. affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. In vitro studies suggest that lumacaftor may induce and ivacaftor may inhibit CYP2B6 substrates. .
- lurasidone
efavirenz decreases levels of lurasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. It may be necessary to increase the lurasidone dose after chronic treatment (ie, 7 days or more) with moderate CYP3A inducers.
lurasidone, efavirenz. Either increases toxicity of the other by Other (see comment). Use Caution/Monitor. Comment: Potential for increased CNS depressant effects when used concurrently; monitor for increased adverse effects and toxicity. - maprotiline
efavirenz and maprotiline both increase QTc interval. Use Caution/Monitor.
- maraviroc
efavirenz will decrease the level or effect of maraviroc by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- marijuana
efavirenz will decrease the level or effect of marijuana by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- medroxyprogesterone
efavirenz will decrease the level or effect of medroxyprogesterone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- mefloquine
efavirenz will decrease the level or effect of mefloquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and mefloquine both increase QTc interval. Use Caution/Monitor. - meloxicam
efavirenz will increase the level or effect of meloxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- meperidine
efavirenz will decrease the level or effect of meperidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Increased toxic metabolite formation.
- mestranol
efavirenz will decrease the level or effect of mestranol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- metaxalone
efavirenz will decrease the level or effect of metaxalone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- methadone
efavirenz will decrease the level or effect of methadone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- methylprednisolone
efavirenz will decrease the level or effect of methylprednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- midazolam
efavirenz will decrease the level or effect of midazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- midazolam intranasal
midazolam intranasal, efavirenz. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Concomitant use of barbiturates, alcohol, or other CNS depressants may increase risk of hypoventilation, airway obstruction, desaturation, or apnea and may contribute to profound and/or prolonged drug effect.
- mifepristone
efavirenz, mifepristone. Other (see comment). Use Caution/Monitor. Comment: Efavirenz shown in vitro to induce CYP3A4 and CYP2B6, but in vitro has been shown to inhibit CYP3A4 and therefore may affect mifepristone levels/effect; mifepristone inhibits CYP2B6, therefore increasing exposure of efavirenz.
- mirtazapine
efavirenz will decrease the level or effect of mirtazapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and mirtazapine both increase QTc interval. Use Caution/Monitor. - mitotane
mitotane decreases levels of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Mitotane is a strong inducer of cytochrome P-4503A4; monitor when coadministered with CYP3A4 substrates for possible dosage adjustments.
- modafinil
efavirenz will decrease the level or effect of modafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nafcillin
nafcillin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Strong CYP3A4 inducers may increase metabolism of CYP3A4 substrates
- naldemedine
efavirenz will decrease the level or effect of naldemedine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Simulation using physiologically-based pharmacokinetic modeling suggests that concomitant use of moderated CYP3A4 inducers decrease exposure to naldemedine. The clinical consequence of this decreased exposure is unknown.
- nefazodone
nefazodone will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nelfinavir
nelfinavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
efavirenz will decrease the level or effect of nelfinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
nelfinavir and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor. - nevirapine
lamivudine and nevirapine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
- nicardipine
efavirenz will decrease the level or effect of nicardipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nifedipine
efavirenz will decrease the level or effect of nifedipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- nilotinib
efavirenz will decrease the level or effect of nilotinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nirmatrelvir
nirmatrelvir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- nirmatrelvir/ritonavir
nirmatrelvir/ritonavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- norgestrel
efavirenz will decrease the level or effect of norgestrel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Moderate CYP3A4 inducers may decrease progestin concentration; consider use of additional barrier methods
- nortriptyline
efavirenz and nortriptyline both increase QTc interval. Use Caution/Monitor.
- octreotide
efavirenz and octreotide both increase QTc interval. Use Caution/Monitor.
- ofloxacin
efavirenz and ofloxacin both increase QTc interval. Use Caution/Monitor.
- olanzapine
efavirenz and olanzapine both increase QTc interval. Use Caution/Monitor. Limited data, including some case reports, suggest that olanzapine may be associated with a significant prolongation of the QTc interval in rare instances
- oliceridine
efavirenz will decrease the level or effect of oliceridine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. If coadministration with a CYP3A4 inducer is necessary, consider increasing oliceridine dose until stable drug effects are achieved; monitor for signs of opioid withdrawal. If inducer is discontinued, consider oliceridine dosage reduction and monitor for signs of respiratory depression.
- olodaterol inhaled
efavirenz and olodaterol inhaled both increase QTc interval. Use Caution/Monitor.
- omeprazole
efavirenz will increase the level or effect of omeprazole by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
efavirenz will decrease the level or effect of omeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - ondansetron
efavirenz will decrease the level or effect of ondansetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- orlistat
orlistat will decrease the level or effect of efavirenz by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Loss of virological control reported in HIV-infected patients taking orlistat concomitantly. Exact mechanism is unclear, but may include a drug-drug interaction that inhibits systemic absorption of the antiretroviral drug. Monitor HIV RNA levels frequently and if increased HIV viral load confirmed, discontinue orlistat.
orlistat will decrease the level or effect of lamivudine by inhibition of GI absorption. Applies only to oral form of both agents. Use Caution/Monitor. Loss of virological control reported in HIV-infected patients taking orlistat concomitantly. Exact mechanism is unclear, but may include a drug-drug interaction that inhibits systemic absorption of the antiretroviral drug. Monitor HIV RNA levels frequently and if increased HIV viral load confirmed, discontinue orlistat. - osilodrostat
efavirenz will decrease the level or effect of osilodrostat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Monitor cortisol concentration and patient?s signs and symptoms during coadministration or discontinuation with strong CYP3A4 inducers. Adjust dose of osilodrostat if necessary.
osilodrostat and efavirenz both increase QTc interval. Use Caution/Monitor. - peginterferon alfa 2a
peginterferon alfa 2a, lamivudine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of liver decompensation.
- ospemifene
efavirenz decreases levels of ospemifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- oxaliplatin
oxaliplatin will increase the level or effect of efavirenz by Other (see comment). Use Caution/Monitor. Monitor for ECG changes if therapy is initiated in patients with drugs known to prolong QT interval.
- oxcarbazepine
oxcarbazepine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- oxycodone
efavirenz decreases levels of oxycodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- palbociclib
efavirenz will decrease the level or effect of palbociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely.
- paricalcitol
efavirenz will decrease the level or effect of paricalcitol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- pasireotide
efavirenz and pasireotide both increase QTc interval. Use Caution/Monitor.
- pazopanib
efavirenz will decrease the level or effect of pazopanib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- peginterferon alfa 2b
peginterferon alfa 2b, lamivudine. Either increases toxicity of the other by pharmacodynamic synergism. Use Caution/Monitor. Increased risk of liver decompensation.
- perphenazine
efavirenz and perphenazine both increase QTc interval. Use Caution/Monitor.
- phenytoin
efavirenz will increase the level or effect of phenytoin by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
phenytoin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. When given together, periodic monitoring for reduced efavirenz efficacy and phenytoin plasma concentrations are recommended .
phenytoin will increase the level or effect of efavirenz by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. - pimavanserin
efavirenz will decrease the level or effect of pimavanserin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration if possible. Monitor for reduced pimavanserin efficacy. An increase in pimavanserin dosage may be needed.
- pimozide
efavirenz will decrease the level or effect of pimozide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- piroxicam
efavirenz will increase the level or effect of piroxicam by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- pitolisant
efavirenz will decrease the level or effect of pitolisant by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Pitolisant exposure is decreased by 50% if coadministered with strong CYP3A4 inducers. For patients stable on pitolisant 8.9 mg/day or 17.8 mg/day, double the pitolisant dose (ie, 17.8 mg or 35.6 mg, respectively) over 7 days. If the strong CYP3A4 inducer is discontinued, reduce pitolisant dosage by half.
- polatuzumab vedotin
efavirenz will decrease the level or effect of polatuzumab vedotin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Polatuzumab undergoes catabolism to small peptides, amino acids, monomethyl auristatin E (MMAE), and unconjugated MMAE-related catabolites. MMAE is a CYP3A4 substrate. Coadministration of polatuzumab vedotin with a strong CYP3A4 inducer may decrease unconjugated MMAE AUC.
- prednisolone
efavirenz will decrease the level or effect of prednisolone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- prednisone
efavirenz will decrease the level or effect of prednisone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- primaquine
efavirenz will decrease the level or effect of primaquine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and primaquine both increase QTc interval. Use Caution/Monitor. - prochlorperazine
efavirenz and prochlorperazine both decrease QTc interval. Use Caution/Monitor.
- progesterone intravaginal gel
efavirenz will decrease the level or effect of progesterone intravaginal gel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- progesterone micronized
efavirenz will decrease the level or effect of progesterone micronized by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- progesterone, natural
efavirenz will decrease the level or effect of progesterone, natural by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- proguanil
efavirenz decreases levels of proguanil by unspecified interaction mechanism. Use Caution/Monitor. May decrease serum concentrations of the active metabolite of proguanil.
- promethazine
efavirenz and promethazine both decrease QTc interval. Use Caution/Monitor.
- protriptyline
efavirenz and protriptyline both increase QTc interval. Use Caution/Monitor.
- quazepam
quazepam will increase the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor.
efavirenz will decrease the level or effect of quazepam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - quetiapine
efavirenz will decrease the level or effect of quetiapine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- quinidine
efavirenz will decrease the level or effect of quinidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ramelteon
efavirenz will increase the level or effect of ramelteon by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- repaglinide
efavirenz will decrease the level or effect of repaglinide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ribavirin
ribavirin increases toxicity of lamivudine by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Use alternatives if available. Increased risk of lactic acidosis.
- ribociclib
efavirenz will decrease the level or effect of ribociclib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration of ribociclib with strong CYP3A inducers should be avoided.
- rifabutin
rifabutin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- rifampin
rifampin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
rifampin will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. - riociguat
efavirenz will decrease the level or effect of riociguat by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Data not available for dose adjustment
- risperidone
efavirenz will decrease the level or effect of risperidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ritonavir
ritonavir and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
ritonavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
efavirenz will decrease the level or effect of ritonavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - rivaroxaban
efavirenz will decrease the level or effect of rivaroxaban by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- saquinavir
saquinavir and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
- roflumilast
efavirenz will decrease the level or effect of roflumilast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration not recommended; strong cytochrome P450 enzyme inducers decrease systemic exposure to roflumilast and may reduce the therapeutic effectiveness
- romidepsin
efavirenz will decrease the level or effect of romidepsin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Coadministration with strong 3A4 inducers should be avoided if possible.
efavirenz and romidepsin both increase QTc interval. Use Caution/Monitor. - rucaparib
rucaparib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Adjust dosage of CYP3A4 substrates, if clinically indicated.
- ruxolitinib
efavirenz will increase the level or effect of ruxolitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ruxolitinib topical
efavirenz will increase the level or effect of ruxolitinib topical by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- salmeterol
efavirenz and salmeterol both increase QTc interval. Use Caution/Monitor.
- saquinavir
efavirenz will decrease the level or effect of saquinavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
saquinavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor. - selexipag
efavirenz will increase the level or effect of selexipag by decreasing metabolism. Modify Therapy/Monitor Closely. Reduce selexipag dose to once daily if coadministered with moderate CYP2C8 inhibitors.
- sertraline
efavirenz will decrease the level or effect of sertraline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and sertraline both increase QTc interval. Use Caution/Monitor. - sildenafil
efavirenz will decrease the level or effect of sildenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Potent CYP3A4 inducers are expected to cause substantial decreases in sildenafil plasma levels
- simvastatin
efavirenz will decrease the level or effect of simvastatin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- solifenacin
efavirenz will decrease the level or effect of solifenacin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and solifenacin both increase QTc interval. Use Caution/Monitor. - sorafenib
efavirenz decreases levels of sorafenib by increasing metabolism. Use Caution/Monitor.
- sparsentan
sparsentan will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Sparsentan (a CYP2B6 inducer) decreases exposure of CYP2B6 substrates and reduces efficacy related to these substrates.
- stavudine
lamivudine and stavudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
efavirenz and stavudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor. - stiripentol
stiripentol, efavirenz. affecting hepatic enzyme CYP2B6 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP2B6 inhibitor and inducer. Monitor CYP2B6 substrates coadministered with stiripentol for increased or decreased effects. CYP2B6 substrates may require dosage adjustment.
stiripentol, efavirenz. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Stiripentol is a CYP3A4 inhibitor and inducer. Monitor CYP3A4 substrates coadministered with stiripentol for increased or decreased effects. CYP3A4 substrates may require dosage adjustment.
stiripentol, efavirenz. Either increases effects of the other by sedation. Use Caution/Monitor. Concomitant use stiripentol with other CNS depressants, including alcohol, may increase the risk of sedation and somnolence. - tenofovir DF
lamivudine and tenofovir DF both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
- sufentanil SL
efavirenz decreases effects of sufentanil SL by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Modify Therapy/Monitor Closely. Coadministration of CYP3A4 inducers may decrease sufentanil levels and efficacy, possibly precipitating withdrawal syndrome in patients who have developed physical dependence to sufentanil. Discontinuation of concomitantly used CYP3A4 inducers may increase sufentanil plasma concentration.
- sulfamethoxazole
efavirenz will increase the level or effect of sulfamethoxazole by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- sunitinib
efavirenz will decrease the level or effect of sunitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tacrolimus
efavirenz and tacrolimus both increase QTc interval. Use Caution/Monitor.
- tadalafil
efavirenz will decrease the level or effect of tadalafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid combination in pulmonary HTN patients. For patients with ED, monitor response to tadalafil carefully because of potential for decreased effectiveness.
- tamoxifen
efavirenz, tamoxifen. affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor. CYP2C9/10 inhibition decreases tamoxifen metabolism to active metabolites.
efavirenz, tamoxifen. affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inhibition decreases metabolism of tamoxifen to N-desmethyl tamoxifen (active metabolite with similar biologic activity). - tamsulosin
efavirenz increases levels of tamsulosin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Dose reduction may be needed for coadministered drugs that are predominantly metabolized by CYP3A.
- tasimelteon
efavirenz will decrease the level or effect of tasimelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid coadministration of tasimelteon with strong CYP3A4 inducers
- tazemetostat
tazemetostat will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tecovirimat
tecovirimat will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Tecovirimat is a weak CYP3A4 inducer. Monitor sensitive CYP3A4 substrates for effectiveness if coadministered.
- telavancin
efavirenz and telavancin both increase QTc interval. Use Caution/Monitor.
- telotristat ethyl
telotristat ethyl will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. Consider increasing dosage of interacting drug, if necessary
- temsirolimus
efavirenz will decrease the level or effect of temsirolimus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- teniposide
efavirenz will decrease the level or effect of teniposide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tenofovir DF
efavirenz and tenofovir DF both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
- terbinafine
efavirenz will decrease the level or effect of terbinafine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tetracycline
efavirenz will decrease the level or effect of tetracycline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- theophylline
efavirenz will decrease the level or effect of theophylline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tiagabine
efavirenz will decrease the level or effect of tiagabine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- ticagrelor
efavirenz decreases levels of ticagrelor by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid use of ticagrelor with potent CYP3A inducers.
- ticlopidine
efavirenz will decrease the level or effect of ticlopidine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
ticlopidine will decrease the level or effect of efavirenz by affecting hepatic enzyme CYP2B6 metabolism. Use Caution/Monitor. - tinidazole
efavirenz will decrease the level or effect of tinidazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- tipranavir
tipranavir and efavirenz both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
tipranavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
tipranavir and lamivudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
efavirenz will decrease the level or effect of tipranavir by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. - tofacitinib
efavirenz increases levels of tofacitinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Loss of, or decreased response to tofacitinib may occur when coadministered with potent CYP3A4 inducers.
- trimethoprim
trimethoprim increases effects of lamivudine by basic (cationic) drug competition for renal tubular clearance. Use Caution/Monitor. Potential for increased toxicity.
- tolbutamide
efavirenz will increase the level or effect of tolbutamide by affecting hepatic enzyme CYP2C9/10 metabolism. Use Caution/Monitor.
- tolterodine
efavirenz will decrease the level or effect of tolterodine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- toremifene
efavirenz decreases levels of toremifene by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. CYP3A4 inducers increase rate of toremifene metabolism, lowering the steady-state concentration in serum.
- tramadol
efavirenz will decrease the level or effect of tramadol by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- trazodone
efavirenz will decrease the level or effect of trazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- triamcinolone acetonide injectable suspension
efavirenz will decrease the level or effect of triamcinolone acetonide injectable suspension by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- triazolam
efavirenz will decrease the level or effect of triazolam by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- triclabendazole
efavirenz and triclabendazole both increase QTc interval. Use Caution/Monitor.
- trifluoperazine
efavirenz and trifluoperazine both decrease QTc interval. Use Caution/Monitor.
- trimipramine
efavirenz will decrease the level or effect of trimipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz will decrease the level or effect of trimipramine by affecting hepatic enzyme CYP2C19 metabolism. Use Caution/Monitor.
efavirenz and trimipramine both increase QTc interval. Use Caution/Monitor. - triptorelin
efavirenz and triptorelin both increase QTc interval. Use Caution/Monitor.
- ublituximab
ublituximab decreases effects of efavirenz by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely.
ublituximab decreases effects of lamivudine by immunosuppressive effects; risk of infection. Modify Therapy/Monitor Closely. - umeclidinium bromide/vilanterol inhaled
efavirenz will decrease the level or effect of umeclidinium bromide/vilanterol inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and umeclidinium bromide/vilanterol inhaled both decrease QTc interval. Use Caution/Monitor. - valganciclovir
valganciclovir, lamivudine. Either increases toxicity of the other by pharmacodynamic synergism. Modify Therapy/Monitor Closely. Use alternatives if available. Increased risk of hematologic toxicity.
- valbenazine
valbenazine and efavirenz both increase QTc interval. Use Caution/Monitor.
- vardenafil
efavirenz will decrease the level or effect of vardenafil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and vardenafil both increase QTc interval. Use Caution/Monitor. - venlafaxine
efavirenz will decrease the level or effect of venlafaxine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
efavirenz and venlafaxine both decrease QTc interval. Use Caution/Monitor. - verapamil
efavirenz will decrease the level or effect of verapamil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- vilanterol/fluticasone furoate inhaled
efavirenz will decrease the level or effect of vilanterol/fluticasone furoate inhaled by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Avoid or Use Alternate Drug.
efavirenz and vilanterol/fluticasone furoate inhaled both increase QTc interval. Use Caution/Monitor. - vilazodone
efavirenz decreases levels of vilazodone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor. Consider increasing vilazodone dose up to 2-fold (not to exceed 80 mg/day) when coadministered with strong CYP3A4 inducers for >14 days.
- vorapaxar
efavirenz decreases levels of vorapaxar by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
- vorinostat
efavirenz and vorinostat both increase QTc interval. Use Caution/Monitor.
- vortioxetine
efavirenz decreases levels of vortioxetine by increasing metabolism. Modify Therapy/Monitor Closely. Consider increasing the vortioxetine dose when coadministered with strong CYP inducers for >14 days; not to exceed 3 times original vortioxetine dose.
- warfarin
efavirenz will decrease the level or effect of warfarin by Other (see comment). Use Caution/Monitor. Warfarin's less potent R-enantiomer is metabolized in part by CYP3A4 (and also CYP1A2 and CYP2C19). Monitor INR more frequently if coadministered with inducers of these isoenzymes and adjust warfarin dose if needed.
- zidovudine
efavirenz and zidovudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor.
lamivudine and zidovudine both increase risk of immune reconstitution syndrome. Use Caution/Monitor. - zonisamide
efavirenz will decrease the level or effect of zonisamide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Use Caution/Monitor.
Minor (100)
- acetazolamide
acetazolamide will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- alosetron
efavirenz will decrease the level or effect of alosetron by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- ambrisentan
efavirenz will decrease the level or effect of ambrisentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- amobarbital
amobarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- anastrozole
anastrozole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- aprepitant
aprepitant will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- armodafinil
armodafinil will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
efavirenz will decrease the level or effect of armodafinil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. - artemether/lumefantrine
artemether/lumefantrine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- atazanavir
atazanavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
efavirenz decreases levels of atazanavir by unspecified interaction mechanism. Minor/Significance Unknown. May be coadministered; see atazanavir monograph for dosing info. - bosentan
bosentan will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
efavirenz will decrease the level or effect of bosentan by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. - butabarbital
butabarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- butalbital
butalbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- caspofungin
efavirenz decreases levels of caspofungin by increasing metabolism. Minor/Significance Unknown.
- cevimeline
efavirenz will decrease the level or effect of cevimeline by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- cimetidine
efavirenz will increase the level or effect of cimetidine by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
- clarithromycin
efavirenz will decrease the level or effect of clarithromycin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- clomipramine
efavirenz will decrease the level or effect of clomipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- cocaine topical
efavirenz will increase the level or effect of cocaine topical by affecting hepatic enzyme CYP2B6 metabolism. Minor/Significance Unknown.
- colchicine
efavirenz will decrease the level or effect of colchicine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- conivaptan
conivaptan will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- cortisone
cortisone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- cyclophosphamide
cyclophosphamide will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- cyclosporine
cyclosporine will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- darifenacin
darifenacin will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- darunavir
darunavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- dasatinib
dasatinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- dexamethasone
dexamethasone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- DHEA, herbal
DHEA, herbal will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- diazepam
efavirenz will increase the level or effect of diazepam by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
- disopyramide
efavirenz will decrease the level or effect of disopyramide by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- dutasteride
efavirenz will decrease the level or effect of dutasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- eplerenone
efavirenz will decrease the level or effect of eplerenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- esomeprazole
efavirenz will increase the level or effect of esomeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
- etravirine
etravirine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- eucalyptus
efavirenz will decrease the level or effect of eucalyptus by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- finasteride
efavirenz will decrease the level or effect of finasteride by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- fluconazole
fluconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- fludrocortisone
fludrocortisone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- fosamprenavir
fosamprenavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- fosaprepitant
fosaprepitant will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- fosphenytoin
fosphenytoin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- galantamine
efavirenz will decrease the level or effect of galantamine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- grapefruit
grapefruit will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- griseofulvin
griseofulvin will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- hydrocortisone
hydrocortisone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- imatinib
efavirenz will decrease the level or effect of imatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- imipramine
efavirenz will decrease the level or effect of imipramine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- indinavir
indinavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- isavuconazonium sulfate
isavuconazonium sulfate will increase the level or effect of lamivudine by Other (see comment). Minor/Significance Unknown. Isavuconazonium sulfate, an OCT2 inhibitor, may increase the effects or levels of OCT2 substrates.
- ketoconazole
efavirenz will decrease the level or effect of ketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- lansoprazole
efavirenz will increase the level or effect of lansoprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
- lapatinib
lapatinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- larotrectinib
larotrectinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- levoketoconazole
efavirenz will decrease the level or effect of levoketoconazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- losartan
efavirenz decreases effects of losartan by decreasing metabolism. Minor/Significance Unknown. May inhibit the conversion of losartan to its active metabolite E-3174. Importance of interaction not established; monitor individual therapeutic response to determine losartan dosage.
- lumefantrine
lumefantrine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- marijuana
marijuana will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- methylprednisolone
methylprednisolone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- metronidazole
metronidazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- miconazole vaginal
miconazole vaginal will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- montelukast
efavirenz will decrease the level or effect of montelukast by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- nelfinavir
nelfinavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- nifedipine
nifedipine will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- nilotinib
nilotinib will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- nimodipine
efavirenz will decrease the level or effect of nimodipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- nitrendipine
efavirenz will decrease the level or effect of nitrendipine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- oxybutynin
efavirenz will decrease the level or effect of oxybutynin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- paclitaxel
efavirenz will decrease the level or effect of paclitaxel by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- paclitaxel protein bound
efavirenz will decrease the level or effect of paclitaxel protein bound by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- pantoprazole
efavirenz will increase the level or effect of pantoprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
- parecoxib
efavirenz will decrease the level or effect of parecoxib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- pentobarbital
pentobarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- phenobarbital
phenobarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- pioglitazone
efavirenz will decrease the level or effect of pioglitazone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- ponatinib
efavirenz decreases levels of ponatinib by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. Avoid unless the coadministration outweighs the possible risk of ponatinib underexposure; monitor for signs of reduced efficacy.
- posaconazole
posaconazole will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- prednisone
prednisone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- primidone
primidone will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- propafenone
efavirenz will decrease the level or effect of propafenone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- quinine
efavirenz will decrease the level or effect of quinine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- quinupristin/dalfopristin
quinupristin/dalfopristin will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- rabeprazole
efavirenz will increase the level or effect of rabeprazole by affecting hepatic enzyme CYP2C19 metabolism. Minor/Significance Unknown.
efavirenz will decrease the level or effect of rabeprazole by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown. - ramelteon
efavirenz will decrease the level or effect of ramelteon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- rifapentine
rifapentine will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- ritonavir
ritonavir will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- rufinamide
rufinamide will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- saxagliptin
efavirenz will decrease the level or effect of saxagliptin by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- secobarbital
secobarbital will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- sufentanil
efavirenz will decrease the level or effect of sufentanil by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- sulfamethoxazole
sulfamethoxazole increases levels of lamivudine by decreasing renal clearance. Minor/Significance Unknown.
- topiramate
topiramate will decrease the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- verapamil
verapamil will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- vinblastine
efavirenz will decrease the level or effect of vinblastine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- vincristine
efavirenz will decrease the level or effect of vincristine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- vincristine liposomal
efavirenz will decrease the level or effect of vincristine liposomal by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- vinorelbine
efavirenz will decrease the level or effect of vinorelbine by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- zafirlukast
zafirlukast will increase the level or effect of efavirenz by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- zaleplon
efavirenz will decrease the level or effect of zaleplon by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
- zidovudine
lamivudine increases effects of zidovudine by pharmacodynamic synergism. Minor/Significance Unknown. Beneficial synergism.
- ziprasidone
efavirenz will decrease the level or effect of ziprasidone by affecting hepatic/intestinal enzyme CYP3A4 metabolism. Minor/Significance Unknown.
Adverse Effects
Listed adverse reactions are Grade 2-4 unless specified
>10%
Rash (18%)
Headache (14%)
Pain (13%)
Diarrhea (11%)
Depression (11%)
Grade 3-4 laboratory abnormalities
- Fasting cholesterol >250 mg/dL (19%)
- Creatine kinase (males: >990 U/L; females >845 U/L) (12%)
1-10%
Fever (8%)
Abdominal pain (7%)
Asthenia (6%)
Anxiety (6%)
Arthralgia (5%)
Insomnia (5%)
Pneumonia (5%)
Myalgia (3%)
Dizziness (3%)
Lipodystrophy (1%)
Peripheral neuropathy (1%)
Grade 3-4 laboratory abnormalities
- Serum amylase >175 U/L (9%)
- AST elevated (5%)
- ALT elevated (4%)
- Hematuria >100 RBC/HPF (7%)
- Neutrophils <750 mg/dL (3%)
- Fasting triglycerides >750 mg/dL (1%)
Postmarketing Reports
Efavirenz
- Body as a whole: Allergic reactions, asthenia, redistribution/accumulation of body fat
- Central and peripheral nervous system: Abnormal coordination, ataxia, cerebellar coordination and balance disturbances, convulsions, hypoesthesia, paresthesia, neuropathy, tremor, vertigo
- Endocrine: Gynecomastia
- Gastrointestinal: Constipation, malabsorption
- Cardiovascular: Flushing, palpitations
- Liver and biliary system: Hepatic enzyme increase, hepatic failure, hepatitis
- Metabolic and nutritional: Hypercholesterolemia, hypertriglyceridemia
- Musculoskeletal: Arthralgia, myalgia, myopathy
- Psychiatric: Aggressive reactions, agitation, delusions, emotional lability, mania, neurosis, paranoia, psychosis, suicide, catatonia
- Respiratory: Dyspnea
- Skin and appendages: Erythema multiforme, photoallergic dermatitis, Stevens-Johnson syndrome
- Special senses: Abnormal vision, tinnitus
Lamivudine
- Body as a whole: Redistribution/accumulation of body fat
- Endocrine and metabolic: Hyperglycemia
- General: Weakness
- Hemic and lymphatic: Anemia (including pure red blood cell aplasia and severe anemias progressing on therapy)
- Hepatic and pancreatic: Lactic acidosis and hepatic steatosis, posttreatment exacerbation of hepatitis B
- Hypersensitivity: Anaphylaxis, urticaria
- Musculoskeletal: Muscle weakness, CPK elevation, rhabdomyolysis
- Skin: Alopecia, pruritus
Tenofovir DF
- Immune system disorders: Allergic reaction, including angioedema
- Metabolism and nutrition disorders: Lactic acidosis, hypokalemia, hypophosphatemia
- Respiratory, thoracic, and mediastinal disorders: Dyspnea
- Gastrointestinal disorders: Pancreatitis, increased amylase, abdominal pain
- Renal and urinary disorders: Renal insufficiency, acute renal failure, renal failure, acute tubular necrosis, Fanconi syndrome, proximal renal tubulopathy, interstitial nephritis (including acute cases), nephrogenic diabetes insipidus, renal insufficiency, increased creatinine, proteinuria, polyuria
- Hepatobiliary disorders: Hepatic steatosis, hepatitis, increased liver enzymes (most commonly AST, ALT gamma GT)
- Skin and subcutaneous tissue disorders: Rash
- Musculoskeletal and connective-tissue disorders: Rhabdomyolysis, osteomalacia (manifested as bone pain and which may contribute to fractures), muscular weakness, myopathy
- General disorders and administration site conditions: Asthenia
Warnings
Black Box Warnings
Severe acute exacerbations of hepatitis B reported in patients coinfected with HBV and HIV-1 and who have discontinued lamivudine or tenofovir DF, 2 components of Symfi Lo
Closely monitor hepatic function in these patients and initiate antihepatitis B treatment if necessary
Contraindications
Documented hypersensitivity (eg, Stevens-Johnson syndrome, erythema multiforme, toxic skin eruptions) to any components contained in the formulation
Coadministration with elbasvir and grazoprevir
Cautions
Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, reported with the use of nucleoside analogs and other ARTs; suspend treatment in any patient who develops clinical or laboratory findings suggestive of lactic acidosis or pronounced hepatotoxicity
Not approved for chronic hepatitis B virus (HBV) infection and the safety and efficacy have not been established in patients coinfected with HBV and HIV-1; if treatment with Epivir-HBV, tenofovir DF, or a tenofovir AF-containing product is prescribed for chronic hepatitis B for a patient with unrecognized or untreated HIV-1 infection, rapid emergence of HIV-1 resistance is likely to result because of the subtherapeutic dose and the inappropriateness of monotherapy HIV-1 treatment (see Black Box Warnings and Dosing Considerations)
Risk of serious psychiatric events (eg, depression, suicidality, paranoia, manic episodes); immediate medical evaluation recommended for serious psychiatric symptoms such as severe depression or suicidal ideation; there have been occasional postmarketing reports of death by suicide, delusions, psychosis like behavior and catatonia; a causal relationship to the use of efavirenz cannot be determined from these reports (see Adverse Effects)
CNS symptoms reported (eg, dizziness, insomnia, impaired concentration, somnolence, abnormal dreams, hallucinations); nervous system symptoms (NSSs) are frequent and usually begin 1-2 days after initiating therapy and resolve in 2-4 weeks; dosing at bedtime may improve tolerability; NSSs are not predictive of onset of psychiatric symptoms
Risk of rash; rashes are usually mild-to-moderate maculopapular skin eruptions that occur within the first 2 weeks of initiating therapy with efavirenz (median time to onset of rash in adults was 11 days) and, in most patients continuing therapy with efavirenz, rash resolves within 1 month
Efavirenz may cause fetal harm when administered during the first trimester to a pregnant woman (see Pregnancy)
Postmarketing cases of hepatitis, including fulminant hepatitis progressing to liver failure requiring transplantation or resulting in death, reported in patients treated with efavirenz; reports included patients with underlying hepatic disease, including coinfection with hepatitis B or C, and patients without preexisting hepatic disease or other identifiable risk factors; monitoring of liver enzymes before and during treatment is recommended for all patients; consider discontinuing treatment in patients with persistent elevations of serum transaminases to greater than 5x ULN; discontinue treatment if elevation of serum transaminases is accompanied by clinical signs or symptoms of hepatitis or hepatic decompensations
Hepatic decompensation, some fatal, reported in HIV-1/HCV co-infected patients receiving combination antiretroviral therapy and interferon and ribavirin-based regimens; monitor for treatment-associated toxicities; discontinue therapy, as medically appropriate, and consider dose reduction or discontinuation of interferon alfa, ribavirin, or both
Immune reconstitution syndrome reported in HIV-infected patients treated with combination ART; during initial phase of combination ART, patients whose immune systems respond may develop an inflammatory response to indolent or residual opportunistic infections (eg, Mycobacterium avium infection, cytomegalovirus, Pneumocystis jirovecii pneumonia (PCP), tuberculosis), and further evaluation and treatment may be necessary
Autoimmune disorders (eg, Grave disease, polymyositis, and Guillain-Barré syndrome, autoimmune hepatitis) reported to occur in the immune reconstitution setting; however, time to onset varies and can occur many months after initiation of treatment
In HIV-infected patients, redistribution/accumulation of body fat (eg, central obesity, dorsocervical fat enlargement [buffalo hump], peripheral wasting, facial wasting, breast enlargement, and cushingoid appearance) observed in patients receiving combination ART
Treatment with efavirenz has resulted in increases in total cholesterol and triglycerides; perform cholesterol and triglyceride testing before initiating efavirenz therapy and at periodic intervals during therapy
Convulsions observed in patients receiving efavirenz, generally in the presence of known medical history of seizures; exercise caution in any patient with a history of seizures
In pediatric patients with a history of prior antiretroviral nucleoside exposure, a history of pancreatitis, or other significant risk factors for the development of pancreatitis, lamivudine should be used with caution
Late-onset neurotoxicity
- Ataxia and encephalopathy (impaired consciousness, confusion, psychomotor slowing, psychosis, delirium), may occur months to years after beginning therapy
- Some events of late-onset neurotoxicity have occurred in patients with CYP2B6 genetic polymorphisms which are associated with increased drug levels despite standard dosing therapy
- Evaluate promptly patients presenting with signs and symptoms of serious neurologic adverse experiences to assess the possibility that these events may be related to therapy, and whether discontinuation is warranted
- Lactic acidosis and severe hepatomegaly with steatosis, including fatal cases, reported with use of nucleoside analogs and other antiretrovirals; female sex and obesity may be risk factors for development of lactic acidosis and severe hepatomegaly with steatosis in patients treated with antiretroviral nucleoside analogues
Bone effects of tenofovir
- In clinical trials, tenofovir DF was associated with slightly greater decreases in bone mineral density and increases in biochemical markers of bone metabolism
- Cases of osteomalacia associated with proximal renal tubulopathy, manifested as bone pain or pain in extremities and which may contribute to fractures, reported
- Persistent or worsening bone pain, pain in extremities, fractures, and/or muscular pain or weakness may be manifestations of proximal renal tubulopathy and should prompt an evaluation of renal function in at-risk patients
- Effects of tenofovir DF-associated changes in BMD and biochemical markers on long-term bone health and future fracture risk in adults and pediatric subjects 2 years and older are unknown
- Long-term effect of lower spine and total body BMD on skeletal growth in pediatric patients, and in particular, effects of long-duration exposure in younger children unknown
- Consider assessment of BMD for adult and pediatric patients who have history of pathologic bone fracture or other risk factors for osteoporosis or bone loss; if bone abnormalities are suspected obtain appropriate consultation
New onset or worsening renal impairment
- Renal impairment (eg, cases of acute renal failure and Fanconi syndrome [eg, renal tubular injury with severe hypophosphatemia]) reported with the use of tenofovir DF
- Assess estimated CrCl in all patients prior to initiating therapy and as clinically appropriate during therapy with tenofovir DF; in patients at risk of renal dysfunction, assess estimated creatinine clearance, serum phosphorus, urine glucose, and urine protein prior to initiation of tenofovir disoproxil fumarate and periodically during tenofovir DF therapy
- Cases of acute renal failure after initiation of high-dose or multiple nonsteroidal anti-inflammatory drugs (NSAIDs) reported in HIV-infected patients with risk factors for renal dysfunction who appeared stable on tenofovir DF; some patients required hospitalization and renal replacement therapy
Drug interactions overview
- Coadministration of Symfi Lo and other ARTs for HIV-1 should be avoided since Symfi Lo is a complete HIV infection
- Concomitant use with other drugs may result in known or potentially significant drug interactions, some of which may lead to loss of therapeutic effects, possible development of resistance, or possible increased effects/toxicities of concomitant drugs
- Since tenofovir is primarily eliminated by the kidneys, coadministration of efavirenz/lamivudine/tenofovir DF with drugs that reduce renal function or compete for active tubular secretion may increase serum concentrations of tenofovir and/or increase the concentrations of other renally eliminated drugs; avoid efavirenz/lamivudine/tenofovir DF with concurrent or recent use of a nephrotoxic agent (eg, high-dose or multiple NSAIDs); consider alternatives to NSAIDs, if needed, in patients at risk for renal dysfunction
- QTc prolongation observed with the use of efavirenz; consider alternatives to efavirenz-containing products when coadministered with a drug with a known risk of torsade de pointes or with patients at higher risk of torsade de pointes
- Patients who are receiving concomitant anticonvulsant medications primarily metabolized by the liver, such as phenytoin and phenobarbital, may require periodic monitoring of plasma levels
- False-positive urine cannabinoid test results reported with some screening assays in uninfected and HIV-infected subjects receiving efavirenz; confirmation of positive screening tests for cannabinoids by a more specific method is recommended Efavirenz has been shown in vivo to induce CYP3A and CYP2B6; efavirenz coadministered with CYP3A or CYP2B6 substrates may result in decreased plasma concentrations
- Drugs that induce CYP3A activity (eg, rifampin, rifabutin) would be expected to increase the clearance of efavirenz, resulting in lowered plasma concentrations; this may lead to loss of virologic response and possibly resistance
- Lamivudine is predominantly eliminated in the urine by active organic cationic secretion; coadministration with drugs eliminated via organic cationic transport system (eg, trimethoprim) may interact with lamivudine
- Coadministration of single doses of lamivudine and sorbitol resulted in a sorbitol dose-dependent reduction in lamivudine exposures; when possible, avoid use of sorbitol-containing medicines with lamivudine
Pregnancy & Lactation
Pregnancy
Advise pregnant women of the potential risk to a fetus
Owing to the potential teratogenic effects, avoid pregnancy in women receiving Symfi Lo
Females of reproductive potential should undergo pregnancy testing before initiation
An ART pregnancy registry has been established (1-800-258-4263); prospective pregnancy data from the Antiviral Pregnancy Registry (APR) not sufficient to adequately assess risk of birth defects or miscarriage
Retrospective case reports of neural tube defects in infants whose mothers were exposed to efavirenz-containing regimens in the first trimester of pregnancy; similar malformations observed in studies conducted in monkeys at doses similar to the human dose; fetal and embryonic toxicities occurred in rats at a dose 10 times less than the human exposure at recommended clinical dose; owing to the potential risk of neural tube defects, do not use in the first trimester of pregnancy
Lamivudine produced embryonic toxicity in rabbits at a dose that produced similar human exposures as the recommended clinical dose; relevance of animal findings to human pregnancy registry data is not known; there are no adequate and well-controlled studies with tenofovir DF in pregnant women; tenofovir DF should be used during pregnancy only if clearly needed
Contraception
- Females of reproductive potential should use effective contraception during and for 12 weeks after discontinuing treatment, owing to the long half-life of efavirenz
- Always use barrier contraception in combination with other methods of contraception
- Hormonal methods that contain progesterone may have decreased effectiveness
Lactation
The Centers for Disease Control and Prevention recommend that HIV-1-infected mothers not breastfeed their infants to avoid risking postnatal transmission of HIV-1 infection
Efavirenz has been shown to pass into human breast milk; no information available on the effects of efavirenz on the breastfed infant or the effects of efavirenz on milk production
Lamivudine is excreted into human milk
Samples of breast milk obtained from five HIV-1-infected mothers in the first postpartum week show that tenofovir is excreted in human milk at low levels; impact of this exposure in breastfed infants is unknown and the effects of tenofovir DF on milk production is unknown
Owing to the potential for HIV transmission (in HIV-negative infants), developing viral resistance (in HIV-positive infants), and adverse reactions in a breastfed infant similar to those seen in adults, instruct mothers not to breastfeed
Pregnancy Categories
A: Generally acceptable. Controlled studies in pregnant women show no evidence of fetal risk.
B: May be acceptable. Either animal studies show no risk but human studies not available or animal studies showed minor risks and human studies done and showed no risk. C: Use with caution if benefits outweigh risks. Animal studies show risk and human studies not available or neither animal nor human studies done. D: Use in LIFE-THREATENING emergencies when no safer drug available. Positive evidence of human fetal risk. X: Do not use in pregnancy. Risks involved outweigh potential benefits. Safer alternatives exist. NA: Information not available.Pharmacology
Mechanism of Action
Tenofovir: NRTI; following hydrolysis and phosphorylation, inhibits HIV-1 reverse transcriptase by competing with AMP as substrate
Lamivudine: NRTI; following phosphorylation, inhibits HIV reverse transcriptase by viral DNA chain termination; cytosine analog
Efavirenz: NNRTI; activity against HIV-1 by binding to reverse transcriptase and consequently blocking the RNA-dependent and DNA-dependent DNA polymerase activities including HIV-1 replication; it does not require intracellular phosphorylation for antiviral activity
Absorption
Efavirenz
- Peak plasma time: 3-5 hr
- Steady-state plasma concentration reached in 6-10 days
Lamivudine
- Peak plasma concentration: 1.5 mcg/mL (2 mg/kg BID)
- Bioavailability: 87% (oral solution)
Peak plasma concentration
- CrCl >60 mL/min, single 300-mg dose: 2.6 mcg/mL
- CrCl 10-30 mL/min, single 300-mg dose: 3.6 mcg/mL
- CrCl <10 mL/min, single 300-mg dose: 6 mcg/mL
AUC
- CrCl >60 mL/min, single 300-mg dose: 11 mcg•hr/mL
- CrCl 10-30 mL/min, single 300-mg dose: 48 mcg•hr/mL
- CrCl <10 mL/min, single 300-mg dose: 157 mcg•hr/mL
Tenofovir DF
- Peak plasma time: 1 hr
- Bioavailability: ~25% (fasted)
Peak plasma concentration
- Fasted; single 300-mg dose: 296 ng/mL
- CrCl >80 mL/min, single 300-mg dose: 0.34 mcg/mL
- CrCl >80 mL/min, single 300-mg dose: 0.34 mcg/mL
- CrCl 50-80 mL/min, single 300-mg dose: 0.33 mcg/mL
- CrCl 30-49 mL/min, single 300-mg dose: 0.37 mcg/mL
- CrCl 12-29 mL/min, single 300-mg dose: 0.6 mcg/mL
AUC
- Fasted; single 300-mg dose: 2287 ng•hr/mL
- CrCl >80 mL/min, single 300-mg dose: 2.18 mcg•hr/mL
- CrCl 50-80 mL/min, single 300-mg dose: 3.06 mcg•hr/mL
- CrCl 30-49 mL/min, single 300-mg dose: 6.01 mcg•hr/mL
- CrCl 12-29 mL/min, single 300-mg dose: 15.98 mcg•hr/mL
Distribution
Efavirenz
- Protein bound: ~99.5-99.75% (human plasma proteins, predominantly albumin)
Lamivudine
- Protein bound: <36%
Tenofovir DF
- Protein bound: <7% (0.01-25 mcg/mL)
Metabolism
Efavirenz
- In vitro studies suggest CYP3A and CYP2B6 are major isozymes responsible for efavirenz metabolism; also shown to induce CYP enzymes, resulting in induction of its own metabolism
Tenofovir DF
- Not by CYP; converted intracellularly by hydrolysis to tenofovir, then phosphorylated to active tenofovir diphosphate
Excretion
Efavirenz
- Half-life: 52-76 hr (single doses); 40-55 hr (multiple doses)
- Excretion: Feces (16-68%)
Lamivudine
- Excretion, trans-sulfoxide metabolite: Urine (5.2%)
- Majority of lamivudine is eliminated unchanged in urine by active organic cationic secretion
- Half-life: 5-7 hr
Tenofovir DF
- Excretion: Urine (~70-80% [unchanged drug])
- Half-life: ~17 hr
Administration
Oral Administration
Oral use only
Take on an empty stomach, preferably at bedtime; dosing at bedtime may improve tolerability of neurologic symptoms
Missed dose
- Missed dose: Take dose as soon as possible
- If it is almost time for next dose, skip missed dose and take next dose at your regular time
Storage
Tablets: Store below 30°C (86°F)
Images
Formulary
Adding plans allows you to compare formulary status to other drugs in the same class.
To view formulary information first create a list of plans. Your list will be saved and can be edited at any time.
Adding plans allows you to:
- View the formulary and any restrictions for each plan.
- Manage and view all your plans together – even plans in different states.
- Compare formulary status to other drugs in the same class.
- Access your plan list on any device – mobile or desktop.