Version July 2025
HIV-1 infection, treatment:
Note: Do not use efavirenz plus abacavir and lamivudine in patients with a pre-antiretroviral therapy HIV RNA ≥100,000 copies/mL (Ref).
Oral: 600 mg once daily, in combination with other appropriate agents; 400 mg once daily may be used in combination with tenofovir disoproxil fumarate and lamivudine (Ref). The 400 mg once daily dose is not recommended in patients who are pregnant (Ref).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
No dosage adjustment necessary (Ref).
Mild impairment (Child-Pugh class A): No dosage adjustment necessary; use with caution.
Moderate-to-severe impairment (Child-Pugh class B or C): Use is not recommended.
Refer to adult dosing.
(For additional information see "Efavirenz: Pediatric drug information")
HIV-1 infection, treatment: Note: Use in combination with other antiretroviral (ARV) agents; gene mutation and ARV resistance patterns should be evaluated (refer to https://www.iasusa.org and https://hivdb.stanford.edu/ for more information).
Infants ≥3 months and Children <3 years:
Dosing based on CYP2B6 genotype: Very limited data available: Note: Efavirenz use is not recommended in patients <3 years of age unless use is unavoidable due to the clinical situation; CYP2B6 genotype testing should be performed prior to therapy initiation, and therapeutic drug monitoring is recommended. The following dosing is investigational but suggested for use in current guidelines (Ref).
Extensive metabolizers (CYP2B6-516-G/G or -G/T genotypes):
5 to <7 kg: Oral: 300 mg once daily.
7 to <14 kg: Oral: 400 mg once daily
14 to ≤17 kg: Oral: 500 mg once daily.
Slow metabolizers (CYP2B6-516-T/T genotype):
5 to <7 kg: Oral: 50 mg once daily.
7 to <14 kg: Oral: 100 mg once daily.
14 to ≤17 kg: Oral: 150 mg once daily.
Manufacturer's labeling: Note: Although FDA approved in pediatric patients ≥3 months of age and weighing ≥3.5 kg, pharmacokinetic data suggest that the FDA-approved regimen may result in underexposure in extensive metabolizers and overexposure in slow metabolizers; dosing is not recommended by expert panel for patients <3 years of age; therapeutic drug monitoring is recommended in this age group regardless of dosing regimen used (Ref).
3.5 to <5 kg: Oral: 100 mg once daily.
5 to <7.5 kg: Oral: 150 mg once daily.
7.5 to <15 kg: Oral: 200 mg once daily.
15 to <20 kg: Oral: 250 mg once daily.
Children ≥3 years and Adolescents:
Fixed dosing (Ref):
7.5 to <15 kg: Oral: 200 mg once daily.
15 to <20 kg: Oral: 250 mg once daily.
20 to <25 kg: Oral: 300 mg once daily.
25 to <32.5 kg: Oral: 350 mg once daily.
32.5 to <40 kg: Oral: 400 mg once daily.
≥40 kg: Oral: 600 mg once daily.
BSA-directed dosing: Oral: 367 mg/m2/dose once daily, maximum dose: 600 mg/dose; recommended by some experts due to concern of underdosing at the upper end of each weight range (Ref).
Dosage adjustment for concomitant therapy: Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
There are no dosage adjustments provided in manufacturer's labeling; however, drug undergoes minimal renal excretion elimination.
Infants ≥3 months, Children, and Adolescents:
Baseline hepatic impairment:
Mild impairment: No dosage adjustment necessary; use with caution.
Moderate to severe impairment: Use not recommended (has not been studied).
Hepatotoxicity during therapy:
Serum transaminases >5 × ULN (persistently): Consider discontinuing therapy.
Serum transaminase elevation AND clinical signs or symptoms of hepatitis or hepatic decompensation: Discontinue therapy.
The following adverse drug reactions and incidences are derived from product labeling unless otherwise specified. Frequency of adverse events is as reported for patients receiving combination antiretroviral therapy.
>10%:
Dermatologic: Skin rash (5% to 32%)
Endocrine & metabolic: Increased serum cholesterol (20% to 40%), increased HDL cholesterol (25% to 35%), increased serum triglycerides (≥751 mg/dL: 6% to 11%)
Gastrointestinal: Diarrhea (3% to 14%)
Nervous system: Central nervous system toxicity (53%), dizziness (2% to 28%), depression (3% to 19%), insomnia (7% to 16%), anxiety (2% to 13%), pain (1% to 13%)
1% to 10%:
Dermatologic: Pruritus (≤9%), erythema multiforme (≤2%)
Endocrine & metabolic: Increased gamma-glutamyl transferase (grades 3/4: 5% to 8%), increased amylase (grades 3/4: grades 3/4: 4% to 6%), hyperglycemia (>250 mg/dL: 2% to 5%)
Gastrointestinal: Nausea (2% to 10%), vomiting (3% to 6%), dyspepsia (4%), abdominal pain (2% to 3%), anorexia (≤2%)
Hematologic & oncologic: Neutropenia (grades 3/4: 2% to 10%)
Hepatic: Increased serum aspartate aminotransferase (grades 3/4: 5% to 8%; incidence higher with hepatitis B and/or C coinfection), increased serum alanine aminotransferase (grades 3/4: 2% to 8%; incidence higher with hepatitis B and/or C coinfection)
Nervous system: Lack of concentration (3% to 8%), fatigue (2% to 8%), headache (2% to 8%), drowsiness (2% to 7%), nervousness (2% to 7%), abnormal dreams (1% to 6%), severe depression (2%), hallucination (1%)
Frequency not defined: Cardiovascular: Prolonged QT interval on ECG
<1%, postmarketing, and/or case reports: Aggressive behavior, agitation, arthralgia, asthenia, ataxia, catatonia, cerebellar ataxia, constipation, delusion, dyspnea, emotional lability, encephalopathy, flushing, fulminant hepatitis, gynecomastia, hepatic failure, hepatitis, hypersensitivity reaction, hypoesthesia, immune reconstitution syndrome, lipotrophy, loss of balance, malabsorption, mania, myalgia, myopathy, neuropathy, palpitations, pancreatitis, paranoid ideation, paresthesia, photodermatitis, psychoneurosis, psychosis, redistribution of body fat, seizure, Stevens-Johnson syndrome, suicidal ideation, suicidal tendencies, tinnitus, tremor, vertigo, visual disturbance
Hypersensitivity (eg, Stevens-Johnson syndrome, erythema multiforme, toxic skin eruptions) to efavirenz or any component of the formulation; concurrent administration with elbasvir or grazoprevir.
Significant drug interactions exist, requiring dose/frequency adjustment or avoidance. Consult drug interactions database for more information.
Canadian labeling: Additional contraindications (not in US labeling): Concurrent administration with cisapride (not available in Canada), ergot derivatives (eg, dihydroergotamine, ergonovine, ergotamine), midazolam, pimozide, St. John's wort, triazolam, voriconazole.
Concerns related to adverse effects:
• CNS effects: May cause CNS effects (eg, abnormal dreams, insomnia, impaired concentration, hallucinations, dizziness, drowsiness); symptoms usually begin within 1 to 2 days after starting efavirenz, and generally resolve within 2 to 4 weeks of continued therapy; dosing at bedtime may improve tolerability; avoid potentially hazardous tasks such as driving or operating machinery. CNS effects may be potentiated when used concomitantly with other psychoactive drugs or ethanol. Late-onset neurotoxicity, including ataxia and encephalopathy, may occur months to years after initiation of efavirenz therapy. Some of these events have been reported in patients with CYP2B6 genetic polymorphisms (associated with increased efavirenz levels at standard doses). Promptly assess patients with signs and symptoms of serious neurologic adverse effects and consider discontinuation of therapy.
• Fat redistribution: May cause redistribution/accumulation of fat (eg, central obesity, dorsocervical fat enlargement [buffalo hump], peripheral wasting, facial wasting, breast enlargement, cushingoid appearance).
• Hepatotoxicity: Hepatitis, including fulminant hepatitis progressing to hepatic failure (sometimes fatal or requiring transplantation), has been reported, including patients with no preexisting hepatic disease or other identifiable risk factors. Monitor liver function tests in all patients; consider discontinuing treatment in patients with persistent serum transaminase elevations >5 x ULN or if serum transaminase elevations are accompanied by signs/symptoms of hepatitis or hepatic decompensation.
• Hypercholesterolemia: Increases in total cholesterol and triglycerides have been reported; screening should be done prior to therapy and periodically throughout treatment.
• Immune reconstitution syndrome: Patients may develop immune reconstitution syndrome resulting in the occurrence of an inflammatory response to an indolent or residual opportunistic infection during initial HIV treatment or activation of autoimmune disorders (eg, Graves disease, polymyositis, Guillain-Barré syndrome, autoimmune hepatitis) later in therapy; further evaluation and treatment may be required.
• Psychiatric effects: Serious psychiatric side effects have been associated with use, including aggressive behavior, delusions, severe depression, suicidal ideation, fatal and nonfatal suicide attempts, paranoia, psychosis-like behavior, and mania; use with caution in patients with a history of mental illness/drug abuse (predisposition to psychological reactions). Patients should be instructed to contact healthcare provider if serious psychiatric effects occur.
• Rash: May cause mild to moderate maculopapular rash; usually occurs within 2 weeks of starting therapy; most resolve within 1 month with continued therapy. Treatment may be reinitiated in patients interrupting therapy for mild to moderate rashes. Discontinue use if severe rash (involving blistering, desquamation, mucosal involvement, or fever) develops; use is contraindicated in patients with a history of a severe cutaneous reaction (eg, Stevens-Johnson syndrome). Pediatric patients are more susceptible to development of rash; prophylactic antihistamines/corticosteroids may be used.
• QT prolongation: QT prolongation has been reported; consider alternative therapy in patients at risk of torsades de pointes or when coadministered with medications with known risk of torsades de pointes.
Disease-related concerns:
• Hepatic impairment: Not recommended in moderate to severe hepatic impairment (Child-Pugh class B or C); use with caution in patients with mild hepatic impairment (Child-Pugh class A), including known or suspected hepatitis B or C infection; monitoring is recommended.
• HIV-associated dementia: Avoid efavirenz-based regimens if possible in patients with HIV-associated dementia; neuropsychiatric side effects of efavirenz may hinder assessment of the effects of antiretrovirals on the improvement of symptoms associated with HIV-associated dementia (HHS [adult] 2023).
• Seizure disorder: Use with caution in patients with a history of seizure disorder; seizures have been associated with use.
Concurrent drug therapy issues:
• Duplicate therapy: Concomitant use of other efavirenz-containing products should be avoided (unless needed for dosage adjustment with concomitant rifampin treatment).
Other warnings/precautions:
• Resistance: Efavirenz administered as monotherapy or added on to a failing regimen may result in rapid viral resistance to efavirenz. Consider cross-resistance when adding antiretroviral agents on to efavirenz therapy.
Efavirenz may cause a rash, which usually presents as mild to moderate pruritic maculopapular skin eruptions but typically does not require discontinuation. Rash is reported more frequently in pediatric patients compared to adults and may be more severe (incidence: adults: 26% to 27%, pediatric patients: 32% to 40%; grade 3 or 4: adults: ~1%, pediatric patients: ~3%) and take longer to appear (median onset: adults: 11 days; pediatric patients: 28 days [range: 3 to 1,642 days]). Rash may be treated with antihistamines and corticosteroids and usually resolves within 1 month while continuing therapy; if therapy is interrupted due to non-severe rash, efavirenz can typically be reinitiated. Discontinue if severe rash (involving blistering, desquamation, mucosal involvement, ulceration, or fever) occurs. Consider prophylaxis with antihistamines in children due to frequency and severity of rash reported in children (HHS [pediatric] 2023; manufacturer's labeling).
Neuropsychiatric effects due to efavirenz may also occur in pediatric patients. The overall reported incidence of CNS adverse effects was 53% (all patients) versus 25% in controls; incidence of neuropsychiatric symptoms in children receiving efavirenz was reported to be 14% in clinical studies and increased to 30% with efavirenz serum concentrations >4 mcg/mL (Puthanakit 2009; Shubber 2013). CNS adverse effects may be more difficult to detect in children because of the challenges assessing neurologic symptoms, such as impaired concentration, sleep disturbances, or behavior disorders, in these patients. Alternate agents are recommended for initial use in pediatric patients; avoid use in patients with psychiatric illness (including depression) or concomitant use with psychoactive drugs. If benefits of use are determined to outweigh risks, administer at bedtime on an empty stomach to lower the risk of and severity of neuropsychiatric effects. Consider evaluation of efavirenz serum concentrations if patient experiences CNS/neuropsychiatric symptoms; may require drug substitution if a suitable alternative exists. Alternatively, after consultation with an expert in pediatric HIV, consider initial dose reduction followed by trough concentration monitoring and potential additional dose adjustment. One study reported an 11% incidence of new-onset seizures in children <36 months of age; late-onset neurologic symptoms (eg, ataxia, encephalopathy) may occur months to years after therapy initiation (HHS [pediatric] 2023).
Efavirenz use is associated with low serum vitamin D levels and low bone mineral density in adults, possibly due to the induction of CYP3A4 and CYP24 enzymes, which impact vitamin D homeostasis. Ensure that calcium, vitamin D, and total caloric intake are sufficient and supplement with vitamin D3 to achieve serum 25-OH-vitamin D concentrations of >30 ng/mL if necessary (HHS [pediatric] 2023].
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
Capsule, Oral:
Sustiva: 50 mg [DSC], 200 mg [DSC]
Generic: 50 mg [DSC], 200 mg [DSC]
Tablet, Oral:
Sustiva: 600 mg [DSC]
Generic: 600 mg
Yes
Tablets (Efavirenz Oral)
600 mg (per each): $20.27 - $37.26
Disclaimer: A representative AWP (Average Wholesale Price) price or price range is provided as reference price only. A range is provided when more than one manufacturer's AWP price is available and uses the low and high price reported by the manufacturers to determine the range. The pricing data should be used for benchmarking purposes only, and as such should not be used alone to set or adjudicate any prices for reimbursement or purchasing functions or considered to be an exact price for a single product and/or manufacturer. Medi-Span expressly disclaims all warranties of any kind or nature, whether express or implied, and assumes no liability with respect to accuracy of price or price range data published in its solutions. In no event shall Medi-Span be liable for special, indirect, incidental, or consequential damages arising from use of price or price range data. Pricing data is updated monthly.
Excipient information presented when available (limited, particularly for generics); consult specific product labeling. [DSC] = Discontinued product
Capsule, Oral:
Sustiva: 50 mg [DSC], 200 mg [DSC] [contains fd&c blue #2 (indigotine,indigo carmine)]
Tablet, Oral:
Sustiva: 600 mg [DSC]
Generic: 600 mg
Oral: Administer on an empty stomach. Dosing at bedtime is recommended to limit central nervous system effects. Tablets must not be broken.
Capsule contents may be sprinkled onto a small amount of soft food (eg, applesauce, grape jelly, yogurt) for patients who cannot swallow capsules. Place 1 to 2 teaspoonfuls of food in a small container. Hold capsule horizontally over container and carefully twist in opposite directions to open, sprinkling contents over food. If more than 1 capsule is needed for a dose, add contents of all capsules needed to 1 to 2 teaspoonfuls of food; do not add more food. Use a small spoon to gently mix capsule contents with food and administer all of mixture to patient. To ensure entire capsule contents are administered, add another 2 teaspoonfuls of food to the container, mix to incorporate any drug residue, and administer. Administer within 30 minutes of mixing. Patient should not consume any additional food or administer additional formula for 2 hours after administration.
Oral: Administer dose at bedtime to decrease CNS adverse effects; administer with water on an empty stomach (administration with food may increase efavirenz concentrations and adverse effects). Capsules and tablets should be swallowed intact.
Patients unable to swallow: The capsules may be opened and added to 1 to 2 teaspoons (5 to 10 mL) of age-appropriate soft food (eg, applesauce, grape jelly, yogurt) or 10 mL of room temperature infant formula. After placing food in a small container, hold capsule horizontally over container and carefully twist in opposite directions to open, sprinkling contents over food. After administration, an additional small amount (2 teaspoons [10 mL]) of food or formula must be added to the empty mixing container, stirred to disperse any remaining efavirenz residue, and administered to the patient. Administer the efavirenz food or formula mixture within 30 minutes of mixing; do not save for future use. No additional food should be consumed for 2 hours after administration. Refer to the detailed "Instructions for Use" (found in the product labeling) for preparing a dose of efavirenz using the capsule sprinkle method. Note: Efavirenz tastes peppery and mixing with grape jelly may improve palatability (Ref).
HIV-1 infection: Treatment of HIV-1 infection in combination with other antiretroviral agents in adults and pediatric patients at least 3 months old and weighing at least 3.5 kg
Substrate of CYP2B6 (Major with inhibitors), CYP2B6 (Minor with inducers), CYP3A4 (Major with inducers), CYP3A4 (Minor with inhibitors); Note: Assignment of Major/Minor substrate status based on clinically relevant drug interaction potential; Induces CYP2B6 (Moderate), CYP2C19 (Weak), CYP3A4 (Moderate), UGT1A1, UGT1A4;
Note: Interacting drugs may not be individually listed below if they are part of a group interaction (eg, individual drugs within “CYP3A4 Inducers [Strong]” are NOT listed). For a complete list of drug interactions by individual drug name and detailed management recommendations, use the drug interactions program by clicking on the “Launch drug interactions program” link above.
Abemaciclib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Abemaciclib. Risk X: Avoid
Abiraterone Acetate: CYP3A4 Inducers (Moderate) may decrease serum concentration of Abiraterone Acetate. Risk C: Monitor
Acalabrutinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Acalabrutinib. Risk C: Monitor
Acoramidis: UGT1A1 Inducers may decrease serum concentration of Acoramidis. Risk X: Avoid
Alcohol (Ethyl): Efavirenz may increase adverse/toxic effects of Alcohol (Ethyl). Specifically, the risk for central nervous system toxicities and hepatotoxicity may be increased. Efavirenz may decrease serum concentration of Alcohol (Ethyl). Risk C: Monitor
ALfentanil: CYP3A4 Inducers (Moderate) may decrease serum concentration of ALfentanil. Management: If concomitant use of alfentanil and moderate CYP3A4 inducers is necessary, consider dosage increase of alfentanil until stable drug effects are achieved. Monitor patients for signs of opioid withdrawal. Risk D: Consider Therapy Modification
Alpelisib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Alpelisib. Risk C: Monitor
ALPRAZolam: CYP3A4 Inducers (Moderate) may decrease serum concentration of ALPRAZolam. Risk C: Monitor
AmLODIPine: CYP3A4 Inducers (Moderate) may decrease serum concentration of AmLODIPine. Risk C: Monitor
Amodiaquine: Efavirenz may increase hepatotoxic effects of Amodiaquine. Efavirenz may increase serum concentration of Amodiaquine. Management: Avoid concurrent use of amodiaquine and efavirenz if possible. If such combination is unavoidable in the pursuit of prompt therapy, monitor closely for patient response and hepatotoxicity. Risk D: Consider Therapy Modification
Antihepaciviral Combination Products: CYP3A4 Inducers (Moderate) may decrease serum concentration of Antihepaciviral Combination Products. Risk X: Avoid
Apremilast: CYP3A4 Inducers (Moderate) may decrease serum concentration of Apremilast. Risk C: Monitor
Aprepitant: CYP3A4 Inducers (Moderate) may decrease serum concentration of Aprepitant. Risk C: Monitor
ARIPiprazole Lauroxil: CYP3A4 Inducers (Moderate) may decrease serum concentration of ARIPiprazole Lauroxil. Risk C: Monitor
ARIPiprazole: CYP3A4 Inducers (Moderate) may decrease serum concentration of ARIPiprazole. Risk C: Monitor
Artemether and Lumefantrine: Efavirenz may decrease serum concentration of Artemether and Lumefantrine. Efavirenz may decrease active metabolite exposure of Artemether and Lumefantrine. Specifically, concentrations of dihydroartemisinin (DHA), the active metabolite of artemether may be decreased. Risk C: Monitor
Atazanavir: Efavirenz may decrease serum concentration of Atazanavir. Management: Only use boosted atazanavir (400 mg daily) with efavirenz in treatment-naive patients. Do not use lower doses of atazanavir, un-boosted atazanavir, or use in treatment-experienced patients. Risk D: Consider Therapy Modification
Atidarsagene Autotemcel: Antiretroviral Agents may decrease therapeutic effects of Atidarsagene Autotemcel. Risk X: Avoid
Atogepant: CYP3A4 Inducers (Moderate) may decrease serum concentration of Atogepant. Management: For treatment of episodic migraine, the recommended dose of atogepant is 30 mg once daily or 60 mg once daily when combined with CYP3A4 inducers. When used for treatment of chronic migraine, use of atogepant with CYP3A4 inducers should be avoided. Risk D: Consider Therapy Modification
Atorvastatin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Atorvastatin. Risk C: Monitor
Atovaquone: Efavirenz may decrease serum concentration of Atovaquone. Management: Consider alternatives to the use of atovaquone with efavirenz when possible. If this combination must be used, monitor for evidence of reduced atovaquone clinical effectiveness. Risk D: Consider Therapy Modification
Atrasentan: CYP3A4 Inducers (Moderate) may decrease serum concentration of Atrasentan. Risk X: Avoid
Avacopan: CYP3A4 Inducers (Moderate) may decrease serum concentration of Avacopan. Risk X: Avoid
Avanafil: CYP3A4 Inducers (Moderate) may decrease serum concentration of Avanafil. Risk X: Avoid
Avapritinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Avapritinib. Risk X: Avoid
Axitinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Axitinib. Management: Concurrent use of axitinib with a moderate CYP3A4 inducer should be avoided when possible. If any such combination is necessary, monitor for reduced axitinib efficacy. Risk D: Consider Therapy Modification
Bedaquiline: CYP3A4 Inducers (Moderate) may decrease serum concentration of Bedaquiline. CYP3A4 Inducers (Moderate) may increase active metabolite exposure of Bedaquiline. Risk X: Avoid
Belumosudil: CYP3A4 Inducers (Moderate) may decrease serum concentration of Belumosudil. Risk C: Monitor
Benzhydrocodone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Benzhydrocodone. Specifically, the serum concentrations of hydrocodone may be reduced. Risk C: Monitor
Betibeglogene Autotemcel: Antiretroviral Agents may decrease therapeutic effects of Betibeglogene Autotemcel. Risk X: Avoid
Bictegravir: UGT1A1 Inducers may decrease serum concentration of Bictegravir. Risk C: Monitor
Bortezomib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Bortezomib. Risk C: Monitor
Bosutinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Bosutinib. Risk C: Monitor
Brexpiprazole: CYP3A4 Inducers (Moderate) may decrease serum concentration of Brexpiprazole. Risk C: Monitor
Brigatinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Brigatinib. Management: Avoid concurrent use of brigatinib with moderate CYP3A4 inducers when possible. If combined, increase the daily dose of brigatinib in 30 mg increments after 7 days of treatment with the current brigatinib dose, up to maximum of twice the dose. Risk D: Consider Therapy Modification
Buprenorphine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Buprenorphine. Risk C: Monitor
BuPROPion: CYP2B6 Inducers (Moderate) may decrease serum concentration of BuPROPion. Risk C: Monitor
BusPIRone: CYP3A4 Inducers (Moderate) may decrease serum concentration of BusPIRone. Risk C: Monitor
Cabotegravir: UGT1A1 Inducers may decrease serum concentration of Cabotegravir. Risk X: Avoid
Cabozantinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Cabozantinib. Management: For cabozantinib tablets (Cabometyx), avoid combined use if possible. If combined, increase cabozantinib by 20 mg from previous dose, max 80 mg daily. For cabozantinib capsules (Cometriq), monitor for reduced cabozantinib efficacy if combined. Risk D: Consider Therapy Modification
Calcifediol: CYP3A4 Inducers (Moderate) may decrease serum concentration of Calcifediol. Risk C: Monitor
Calcitriol (Systemic): CYP3A4 Inducers (Moderate) may decrease serum concentration of Calcitriol (Systemic). Risk C: Monitor
Cannabis: CYP3A4 Inducers (Moderate) may decrease serum concentration of Cannabis. More specifically, tetrahydrocannabinol and cannabidiol serum concentrations may be decreased. Risk C: Monitor
Capivasertib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Capivasertib. Risk X: Avoid
Capmatinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Capmatinib. Risk X: Avoid
CarBAMazepine: May decrease serum concentration of Efavirenz. Efavirenz may decrease serum concentration of CarBAMazepine. Risk X: Avoid
Cariprazine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Cariprazine. Risk X: Avoid
Caspofungin: Inducers of Drug Clearance may decrease serum concentration of Caspofungin. Management: Consider using an increased caspofungin dose of 70 mg daily in adults (or 70 mg/m2, up to a maximum of 70 mg, daily in pediatric patients) when coadministered with known inducers of drug clearance. Risk D: Consider Therapy Modification
Ceritinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ceritinib. Risk C: Monitor
Clarithromycin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Clarithromycin. CYP3A4 Inducers (Moderate) may increase active metabolite exposure of Clarithromycin. Management: Consider alternative antimicrobial therapy for patients receiving a CYP3A4 inducer. Drugs that enhance the metabolism of clarithromycin into 14-hydroxyclarithromycin may alter the clinical activity of clarithromycin and impair its efficacy. Risk D: Consider Therapy Modification
Clindamycin (Systemic): CYP3A4 Inducers (Moderate) may decrease serum concentration of Clindamycin (Systemic). Risk C: Monitor
CloZAPine: CYP3A4 Inducers (Moderate) may decrease serum concentration of CloZAPine. Risk C: Monitor
Cobicistat: CYP3A4 Inducers (Moderate) may decrease serum concentration of Cobicistat. Risk C: Monitor
Cobimetinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Cobimetinib. Risk X: Avoid
Codeine: CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Codeine. Risk C: Monitor
Copanlisib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Copanlisib. Risk C: Monitor
Crinecerfont: CYP3A4 Inducers (Moderate) may decrease serum concentration of Crinecerfont. Management: Double the evening dose of crinecerfont and continue the morning dose unchanged during coadministration with moderate CYP3A4 inducers. See full interaction monograph for details. Risk D: Consider Therapy Modification
Crizotinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Crizotinib. Risk C: Monitor
CycloPHOSphamide: CYP2B6 Inducers (Moderate) may increase active metabolite exposure of CycloPHOSphamide. Risk C: Monitor
CycloSPORINE (Systemic): CYP3A4 Inducers (Moderate) may decrease serum concentration of CycloSPORINE (Systemic). Risk C: Monitor
CYP3A4 Inducers (Moderate): May decrease serum concentration of Efavirenz. Risk C: Monitor
CYP3A4 Inducers (Strong): May decrease serum concentration of Efavirenz. Risk C: Monitor
Daclatasvir: CYP3A4 Inducers (Moderate) may decrease serum concentration of Daclatasvir. Management: Increase the daclatasvir dose to 90 mg once daily if used with a moderate CYP3A4 inducer. Risk D: Consider Therapy Modification
Dapsone (Systemic): CYP3A4 Inducers (Moderate) may decrease serum concentration of Dapsone (Systemic). Risk C: Monitor
Daridorexant: CYP3A4 Inducers (Moderate) may decrease serum concentration of Daridorexant. Risk X: Avoid
Darunavir: May increase serum concentration of Efavirenz. Efavirenz may decrease serum concentration of Darunavir. Management: Monitor for decreased concentrations and effects of darunavir and/or increased concentrations and effects of efavirenz when darunavir/ritonavir is combined with efavirenz. The use of darunavir/cobicistat in combination with efavirenz is not recommended. Risk D: Consider Therapy Modification
Dasabuvir: CYP3A4 Inducers (Moderate) may decrease serum concentration of Dasabuvir. Risk X: Avoid
Dasatinib: CYP3A4 Inducers (Moderate) may increase serum concentration of Dasatinib. Risk C: Monitor
Deferasirox: UGT1A1 Inducers may decrease serum concentration of Deferasirox. Management: Avoid concomitant use of deferasirox and UGT1A1 inducers when possible. If combined, consider a 50% increase in the initial deferasirox dose, with monitoring of serum ferritin concentrations and clinical response to guide further dosing. Risk D: Consider Therapy Modification
Deflazacort: CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Deflazacort. Risk X: Avoid
DexAMETHasone (Systemic): CYP3A4 Inducers (Moderate) may decrease serum concentration of DexAMETHasone (Systemic). Risk C: Monitor
DiazePAM: CYP3A4 Inducers (Moderate) may decrease serum concentration of DiazePAM. Risk C: Monitor
Dienogest: CYP3A4 Inducers (Moderate) may decrease serum concentration of Dienogest. Risk C: Monitor
DilTIAZem: CYP3A4 Inducers (Moderate) may decrease serum concentration of DilTIAZem. Risk C: Monitor
Disopyramide: CYP3A4 Inducers (Moderate) may decrease serum concentration of Disopyramide. Risk C: Monitor
Dolutegravir: Efavirenz may decrease serum concentration of Dolutegravir. Management: Increase dolutegravir to 50 mg twice/day in adults. Increase weight-based dose to twice daily in pediatric patients. Recommendations vary for combo products; see interaction monograph for details. Not recommended with Dovato or Juluca brand combos. Risk D: Consider Therapy Modification
DOXOrubicin (Conventional): CYP3A4 Inducers (Moderate) may decrease serum concentration of DOXOrubicin (Conventional). Risk X: Avoid
DroNABinol: CYP3A4 Inducers (Moderate) may decrease serum concentration of DroNABinol. Risk C: Monitor
Dronedarone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Dronedarone. Risk C: Monitor
Duvelisib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Duvelisib. Management: Avoid if possible. If used, on day 12 of combination increase duvelisib from 25 mg twice daily to 40 mg twice daily or from 15 mg twice daily to 25 mg twice daily. Resume prior duvelisib dose 14 days after stopping moderate CYP3A4 inducer. Risk D: Consider Therapy Modification
Dydrogesterone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Dydrogesterone. Risk C: Monitor
Elacestrant: CYP3A4 Inducers (Moderate) may decrease serum concentration of Elacestrant. Risk X: Avoid
Elbasvir and Grazoprevir: Efavirenz may decrease serum concentration of Elbasvir and Grazoprevir. Risk X: Avoid
Elexacaftor, Tezacaftor, and Ivacaftor: CYP3A4 Inducers (Moderate) may decrease serum concentration of Elexacaftor, Tezacaftor, and Ivacaftor. Risk C: Monitor
Eliglustat: CYP3A4 Inducers (Moderate) may decrease serum concentration of Eliglustat. Risk C: Monitor
Elivaldogene Autotemcel: Antiretroviral Agents may decrease therapeutic effects of Elivaldogene Autotemcel. Management: Avoid use of antiretroviral medications for at least one month, or for the amount of time required for elimination of the retroviral medication, prior to stem cell mobilization and until the all apheresis cycles are finished Risk X: Avoid
Encorafenib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Encorafenib. Risk C: Monitor
Ensartinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ensartinib. Risk X: Avoid
Entrectinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Entrectinib. Risk X: Avoid
Enzalutamide: CYP3A4 Inducers (Moderate) may decrease serum concentration of Enzalutamide. CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Enzalutamide. Risk C: Monitor
Erdafitinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Erdafitinib. Management: If a moderate CYP3A4 inducer must be used at the start of erdafitinib, administer erdafitinib at a dose of 9 mg daily. If a moderate CYP3A4 inducer is discontinued, continue erdafitinib at the same dose unless there is evidence of drug toxicity. Risk D: Consider Therapy Modification
Ergonovine: Reverse Transcriptase Inhibitors (Non-Nucleoside) may increase serum concentration of Ergonovine. Specifically, this would be most likely with delavrdine, while other Non-Nucleoside Reverse Transcriptase Inhibitors may be more likely to decrease the concentration of Ergonovine. Risk X: Avoid
Erlotinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Erlotinib. Management: Avoid the combination of erlotinib and strong CYP3A4 inducers whenever possible. If this combination must be used, increase erlotinib dose by 50 mg increments every 2 weeks as tolerated, to a maximum of 450 mg/day. Risk D: Consider Therapy Modification
Estrogen Derivatives: CYP3A4 Inducers (Moderate) may decrease serum concentration of Estrogen Derivatives. Risk C: Monitor
Etoposide Phosphate: CYP3A4 Inducers (Moderate) may decrease serum concentration of Etoposide Phosphate. Risk C: Monitor
Etoposide: CYP3A4 Inducers (Moderate) may decrease serum concentration of Etoposide. Risk C: Monitor
Everolimus: CYP3A4 Inducers (Moderate) may decrease serum concentration of Everolimus. Risk C: Monitor
Exemestane: CYP3A4 Inducers (Moderate) may decrease serum concentration of Exemestane. Risk C: Monitor
Fedratinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Fedratinib. Risk X: Avoid
Felodipine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Felodipine. Risk C: Monitor
FentaNYL: CYP3A4 Inducers (Moderate) may decrease serum concentration of FentaNYL. Risk C: Monitor
Fexinidazole: CYP3A4 Inducers (Moderate) may increase active metabolite exposure of Fexinidazole. Risk X: Avoid
Finerenone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Finerenone. Risk X: Avoid
Flibanserin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Flibanserin. Risk X: Avoid
Fosamprenavir: Efavirenz may decrease active metabolite exposure of Fosamprenavir. Management: For once-daily fosamprenavir/ritonavir with efavirenz, increase ritonavir dose to 300 mg/day in adult patients. No ritonavir dose adjustment is required if using twice-daily fosamprenavir/ritonavir. Risk D: Consider Therapy Modification
Fosaprepitant: CYP3A4 Inducers (Moderate) may decrease serum concentration of Fosaprepitant. Specifically, CYP3A4 Inducers (Moderate) may decrease serum concentrations of the active metabolite aprepitant. Risk C: Monitor
Fosnetupitant: CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Fosnetupitant. Risk C: Monitor
Fosphenytoin-Phenytoin: May decrease serum concentration of Efavirenz. Efavirenz may decrease serum concentration of Fosphenytoin-Phenytoin. Risk C: Monitor
Fostamatinib: CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Fostamatinib. Risk C: Monitor
Fruquintinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Fruquintinib. Management: Avoid this combination when possible. If combined, continue the same fruquintinib dose, but monitor for reduced fruquintinib efficacy. Risk D: Consider Therapy Modification
Ganaxolone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ganaxolone. Management: Avoid concomitant use of ganaxolone and moderate CYP3A4 inducers whenever possible. If combined, consider increasing the dose of ganaxolone, but do not exceed the maximum recommended daily dose. Risk D: Consider Therapy Modification
Gefitinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Gefitinib. Risk C: Monitor
Gemigliptin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Gemigliptin. CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Gemigliptin. Risk C: Monitor
Gepirone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Gepirone. Risk C: Monitor
Gepotidacin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Gepotidacin. Risk C: Monitor
Ginkgo Biloba: May decrease serum concentration of Efavirenz. Risk C: Monitor
Glasdegib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Glasdegib. Management: Avoid use of glasdegib and moderate CYP3A4 inducers whenever possible. If combined, increase glasdegib dose from 100 mg daily to 200 mg daily or from 50 mg daily to 100 mg daily. Resume previous glasdegib dose 7 days after discontinuation of the inducer. Risk D: Consider Therapy Modification
Glecaprevir and Pibrentasvir: Efavirenz may decrease serum concentration of Glecaprevir and Pibrentasvir. Risk X: Avoid
GuanFACINE: CYP3A4 Inducers (Moderate) may decrease serum concentration of GuanFACINE. Management: Increase extended-release guanfacine dose by up to double when initiating guanfacine in patients taking CYP3A4 inducers or if initiating a CYP3A4 inducer in a patient already taking extended-release guanfacine. Monitor for reduced guanfacine efficacy. Risk D: Consider Therapy Modification
Haloperidol: QT-prolonging Agents (Indeterminate Risk - Avoid) may increase QTc-prolonging effects of Haloperidol. Risk C: Monitor
Hormonal Contraceptives: Efavirenz may decrease serum concentration of Hormonal Contraceptives. Management: Use a back-up method during coadministration, and to continue back-up contraception for 12 weeks after stopping efavirenz to ensure contraceptive reliability. Injected depot medroxyprogesterone acetate does not appear to participate in this interaction. Risk D: Consider Therapy Modification
Horsetail: May decrease therapeutic effects of Efavirenz. Risk C: Monitor
HYDROcodone: CYP3A4 Inducers (Moderate) may decrease serum concentration of HYDROcodone. Risk C: Monitor
Hydrocortisone (Systemic): CYP3A4 Inducers (Moderate) may decrease serum concentration of Hydrocortisone (Systemic). Risk C: Monitor
Ibrexafungerp: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ibrexafungerp. Risk X: Avoid
Ibrutinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ibrutinib. Risk C: Monitor
Idelalisib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Idelalisib. Risk C: Monitor
Ifosfamide: CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Ifosfamide. CYP3A4 Inducers (Moderate) may increase active metabolite exposure of Ifosfamide. Risk C: Monitor
Imatinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Imatinib. Risk C: Monitor
Indinavir: Efavirenz may decrease serum concentration of Indinavir. Management: The appropriate dose adjustments for indinavir when used together with efavirenz are unknown. The use of higher unboosted indinavir doses is not likely an adequate approach. Use of a ritonavir-boosted indinavir regimen could be considered. Risk D: Consider Therapy Modification
Irinotecan Products: CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Irinotecan Products. Specifically, concentrations of SN-38 may be reduced. Risk C: Monitor
Isavuconazonium Sulfate: CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Isavuconazonium Sulfate. Specifically, CYP3A4 Inducers (Moderate) may decrease isavuconazole serum concentrations. Risk C: Monitor
Isradipine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Isradipine. Risk C: Monitor
Istradefylline: CYP3A4 Inducers (Moderate) may decrease serum concentration of Istradefylline. Risk C: Monitor
Itraconazole: Efavirenz may decrease serum concentration of Itraconazole. Efavirenz may decrease active metabolite exposure of Itraconazole. Risk X: Avoid
Ivabradine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ivabradine. Risk X: Avoid
Ivacaftor: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ivacaftor. Risk C: Monitor
Ixabepilone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ixabepilone. Risk C: Monitor
Ixazomib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ixazomib. Risk C: Monitor
Ketamine: CYP2B6 Inducers (Moderate) may decrease serum concentration of Ketamine. Risk C: Monitor
Ketoconazole (Systemic): Efavirenz may decrease serum concentration of Ketoconazole (Systemic). Management: The use of ketoconazole concurrently with or within 2 weeks of efavirenz is not recommended. If such a combination cannot be avoided, monitor patients closely for evidence of diminished clinical response to ketoconazole. Risk D: Consider Therapy Modification
Lapatinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Lapatinib. Risk C: Monitor
Larotrectinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Larotrectinib. Management: Double the larotrectinib dose if used together with a moderate CYP3A4 inducer. Following discontinuation of the moderate CYP3A4 inducer, resume the previous dose of larotrectinib after a period of 3 to 5 times the inducer's half-life. Risk D: Consider Therapy Modification
Lazertinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Lazertinib. Risk X: Avoid
Lefamulin (Intravenous): CYP3A4 Inducers (Moderate) may decrease serum concentration of Lefamulin (Intravenous). Management: Avoid concomitant use of lefamulin (intravenous) with moderate CYP3A4 inducers unless the benefits outweigh the risks. Risk D: Consider Therapy Modification
Lefamulin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Lefamulin. Management: Avoid concomitant use of lefamulin with moderate CYP3A4 inducers unless the benefits outweigh the risks. Risk D: Consider Therapy Modification
Lemborexant: CYP3A4 Inducers (Moderate) may decrease serum concentration of Lemborexant. Risk X: Avoid
Lenacapavir: CYP3A4 Inducers (Moderate) may decrease serum concentration of Lenacapavir. Risk X: Avoid
Leniolisib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Leniolisib. Risk X: Avoid
Lercanidipine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Lercanidipine. Risk C: Monitor
Letermovir: UGT1A1 Inducers may decrease serum concentration of Letermovir. Risk X: Avoid
Levamlodipine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Levamlodipine. Risk C: Monitor
Levoketoconazole: Efavirenz may decrease serum concentration of Levoketoconazole. Risk X: Avoid
Levomethadone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Levomethadone. Risk C: Monitor
Levomethadone: Reverse Transcriptase Inhibitors (Non-Nucleoside) may decrease serum concentration of Levomethadone. Management: Levomethadone dosage adjustments will likely be required with efavirenz and nevirapine, and may be necessary with rilpivirine as well. Risk C: Monitor
LinaGLIPtin: CYP3A4 Inducers (Moderate) may decrease serum concentration of LinaGLIPtin. Risk C: Monitor
Lonafarnib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Lonafarnib. Risk X: Avoid
Lopinavir: Efavirenz may decrease serum concentration of Lopinavir. Management: Avoid once daily use of lopinavir/ritonavir with efavirenz. Avoid use of this combination in patients less than 6 months of age. Lopinavir/ritonavir dose adjustments are required for patients taking twice daily lopinavir/ritonavir. See full monograph. Risk D: Consider Therapy Modification
Lorlatinib: CYP3A4 Inducers (Moderate) may increase hepatotoxic effects of Lorlatinib. CYP3A4 Inducers (Moderate) may decrease serum concentration of Lorlatinib. Management: Avoid use of lorlatinib with moderate CYP3A4 inducers. If such a combination must be used, increase lorlatinib to 125 mg daily. Monitor for reduced lorlatinib efficacy and consider closer monitoring of AST, ALT, and bilirubin. Risk D: Consider Therapy Modification
Lovastatin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Lovastatin. Risk C: Monitor
Lovotibeglogene Autotemcel: Antiretroviral Agents may decrease therapeutic effects of Lovotibeglogene Autotemcel. Risk X: Avoid
Lumacaftor and Ivacaftor: CYP3A4 Inducers (Moderate) may decrease serum concentration of Lumacaftor and Ivacaftor. Risk C: Monitor
Lumateperone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Lumateperone. Risk X: Avoid
Lurasidone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Lurasidone. Management: After chronic treatment (7 days or more) with a moderate CYP3A4 inducer, lurasidone dose increases may be needed. Monitor closely for decreased lurasidone effects and increase the lurasidone dose as needed. Risk D: Consider Therapy Modification
Macimorelin: Coadministration of Efavirenz and Macimorelin may alter diagnostic results. Risk C: Monitor
Macitentan: CYP3A4 Inducers (Moderate) may decrease serum concentration of Macitentan. Risk C: Monitor
Maraviroc: CYP3A4 Inducers (Moderate) may decrease serum concentration of Maraviroc. Management: Increase maraviroc adult dose to 600 mg twice/day, but only if not receiving a strong CYP3A4 inhibitor. Not recommended for pediatric patients not also receiving a strong CYP3A4 inhibitor. Contraindicated in patients with CrCl less than 30 mL/min. Risk D: Consider Therapy Modification
Maribavir: CYP3A4 Inducers (Moderate) may decrease serum concentration of Maribavir. Risk C: Monitor
Mavacamten: CYP3A4 Inducers (Moderate) may decrease serum concentration of Mavacamten. Risk X: Avoid
Mavorixafor: CYP3A4 Inducers (Moderate) may decrease serum concentration of Mavorixafor. Risk C: Monitor
Mefloquine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Mefloquine. Risk C: Monitor
Meperidine: CYP2B6 Inducers (Moderate) may decrease serum concentration of Meperidine. CYP2B6 Inducers (Moderate) may increase active metabolite exposure of Meperidine. Specifically, concentrations of normeperidine, the CNS stimulating metabolite, may be increased. Risk C: Monitor
Methadone: Reverse Transcriptase Inhibitors (Non-Nucleoside) may increase metabolism of Methadone. Management: Methadone dosage adjustments will likely be required with efavirenz and nevirapine, and may be necessary with rilpivirine as well. Risk C: Monitor
Methoxyflurane: CYP2B6 Inducers (Moderate) may increase metabolism of Methoxyflurane. Specifically, this increased metabolism may lead to increased production of nephrotoxic metabolites. Risk X: Avoid
MethylPREDNISolone: CYP3A4 Inducers (Moderate) may decrease serum concentration of MethylPREDNISolone. Risk C: Monitor
Mianserin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Mianserin. Risk C: Monitor
Midazolam: CYP3A4 Inducers (Moderate) may decrease serum concentration of Midazolam. Risk C: Monitor
Midostaurin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Midostaurin. Risk C: Monitor
MiFEPRIStone: CYP3A4 Inducers (Moderate) may decrease serum concentration of MiFEPRIStone. Management: Avoid combined use in patients treated for Cushing's disease. When used for pregnancy termination, mifepristone efficacy may be reduced and an alternative pregnancy termination procedure may be warranted. Ensure a follow-up assessment after combined use. Risk D: Consider Therapy Modification
Mirodenafil: CYP3A4 Inducers (Moderate) may decrease serum concentration of Mirodenafil. Risk C: Monitor
Mitapivat: CYP3A4 Inducers (Moderate) may decrease serum concentration of Mitapivat. Management: Consider alternatives to this combination when possible. If combined, monitor hemoglobin and titrate mitapivat beyond 50 mg twice daily, if needed, but do not exceed doses of 100 mg twice daily. Risk D: Consider Therapy Modification
Mobocertinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Mobocertinib. CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Mobocertinib. Risk X: Avoid
Montelukast: CYP3A4 Inducers (Moderate) may decrease serum concentration of Montelukast. Risk C: Monitor
Naldemedine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Naldemedine. Risk C: Monitor
Naloxegol: CYP3A4 Inducers (Moderate) may decrease serum concentration of Naloxegol. Risk C: Monitor
Nelfinavir: CYP3A4 Inducers (Moderate) may decrease serum concentration of Nelfinavir. Risk C: Monitor
Neratinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Neratinib. Risk X: Avoid
Netupitant: CYP3A4 Inducers (Moderate) may decrease serum concentration of Netupitant. Risk C: Monitor
NIFEdipine: CYP3A4 Inducers (Moderate) may decrease serum concentration of NIFEdipine. Risk C: Monitor
Nilotinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Nilotinib. Risk C: Monitor
Nilvadipine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Nilvadipine. Risk C: Monitor
NiMODipine: CYP3A4 Inducers (Moderate) may decrease serum concentration of NiMODipine. Risk C: Monitor
Nirmatrelvir and Ritonavir: Efavirenz may increase adverse/toxic effects of Nirmatrelvir and Ritonavir. Efavirenz may decrease serum concentration of Nirmatrelvir and Ritonavir. Specifically, efavirenz may decrease concentration of nirmatrelvir. Efavirenz may increase serum concentration of Nirmatrelvir and Ritonavir. Specifically, efavirenz may increase concentration of ritonavir. Nirmatrelvir and Ritonavir may increase serum concentration of Efavirenz. Risk C: Monitor
Nirogacestat: CYP3A4 Inducers (Moderate) may decrease serum concentration of Nirogacestat. Risk X: Avoid
Nisoldipine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Nisoldipine. Risk X: Avoid
Olaparib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Olaparib. Risk X: Avoid
Oliceridine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Oliceridine. Risk C: Monitor
Olmutinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Olmutinib. Risk C: Monitor
Olutasidenib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Olutasidenib. Risk X: Avoid
Omaveloxolone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Omaveloxolone. Risk X: Avoid
Orlistat: May decrease serum concentration of Antiretroviral Agents. Risk C: Monitor
Osimertinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Osimertinib. Risk C: Monitor
OxyCODONE: CYP3A4 Inducers (Moderate) may decrease serum concentration of OxyCODONE. Risk C: Monitor
PACLitaxel (Conventional): CYP3A4 Inducers (Moderate) may decrease serum concentration of PACLitaxel (Conventional). Risk C: Monitor
PACLitaxel (Protein Bound): CYP3A4 Inducers (Moderate) may decrease serum concentration of PACLitaxel (Protein Bound). Risk C: Monitor
Pacritinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Pacritinib. Risk C: Monitor
Palbociclib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Palbociclib. Risk C: Monitor
Paliperidone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Paliperidone. Risk C: Monitor
Palovarotene: CYP3A4 Inducers (Moderate) may decrease serum concentration of Palovarotene. Risk X: Avoid
PAZOPanib: CYP3A4 Inducers (Moderate) may decrease serum concentration of PAZOPanib. Risk C: Monitor
Pemigatinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Pemigatinib. Risk X: Avoid
Perampanel: CYP3A4 Inducers (Moderate) may decrease serum concentration of Perampanel. Management: Increase perampanel starting dose to 4 mg/day if used with moderate CYP3A4 inducers. Increase perampanel dose by 2 mg/day no more than once weekly based on response and tolerability. Dose adjustments may be needed if the inducer is discontinued. Risk D: Consider Therapy Modification
Pimavanserin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Pimavanserin. Risk X: Avoid
Piperaquine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Piperaquine. Risk C: Monitor
Pirtobrutinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Pirtobrutinib. Management: Avoid concomitant use if possible. If combined, if the current pirtobrutinib dose is 200 mg once daily, increase to 300 mg once daily. If current pirtobrutinib dose is 50 mg or 100 mg once daily, increase the dose by 50 mg. Risk D: Consider Therapy Modification
PONATinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of PONATinib. Risk C: Monitor
Posaconazole: Efavirenz may decrease serum concentration of Posaconazole. Risk X: Avoid
Pralsetinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Pralsetinib. Management: If this combo cannot be avoided, increase pralsetinib dose from 400 mg daily to 600 mg daily; from 300 mg daily to 500 mg daily; and from 200 mg daily to 300 mg daily. Risk D: Consider Therapy Modification
Pravastatin: Efavirenz may decrease serum concentration of Pravastatin. Risk C: Monitor
Praziquantel: CYP3A4 Inducers (Moderate) may decrease serum concentration of Praziquantel. Management: Consider alternatives to this combination whenever possible. If combined, monitor closely for reduced praziquantel efficacy. If possible, stop the moderate CYP3A4 inducer 2 to 4 weeks before praziquantel initiation. Risk D: Consider Therapy Modification
PrednisoLONE (Systemic): CYP3A4 Inducers (Moderate) may decrease serum concentration of PrednisoLONE (Systemic). Risk C: Monitor
PredniSONE: CYP3A4 Inducers (Moderate) may decrease serum concentration of PredniSONE. Risk C: Monitor
Pretomanid: CYP3A4 Inducers (Moderate) may decrease serum concentration of Pretomanid. Risk X: Avoid
Proguanil: Efavirenz may decrease serum concentration of Proguanil. Efavirenz may decrease active metabolite exposure of Proguanil. Efavirenz may increase serum concentration of Proguanil. Risk C: Monitor
QT-prolonging Agents (Highest Risk): QT-prolonging Agents (Indeterminate Risk - Avoid) may increase QTc-prolonging effects of QT-prolonging Agents (Highest Risk). Management: Monitor for QTc interval prolongation and ventricular arrhythmias when these agents are combined. Patients with additional risk factors for QTc prolongation may be at even higher risk. Risk C: Monitor
QUEtiapine: CYP3A4 Inducers (Moderate) may decrease serum concentration of QUEtiapine. Risk C: Monitor
QuiNIDine: CYP3A4 Inducers (Moderate) may decrease serum concentration of QuiNIDine. Risk C: Monitor
QuiNINE: CYP3A4 Inducers (Moderate) may decrease serum concentration of QuiNINE. Risk C: Monitor
Quizartinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Quizartinib. Risk X: Avoid
Ranolazine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ranolazine. Risk X: Avoid
Red Yeast Rice: Efavirenz may decrease serum concentration of Red Yeast Rice. Risk C: Monitor
Regorafenib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Regorafenib. CYP3A4 Inducers (Moderate) may increase active metabolite exposure of Regorafenib. Risk C: Monitor
Repaglinide: CYP3A4 Inducers (Moderate) may decrease serum concentration of Repaglinide. Risk C: Monitor
Repotrectinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Repotrectinib. Risk X: Avoid
Reverse Transcriptase Inhibitors (Non-Nucleoside): May increase adverse/toxic effects of Reverse Transcriptase Inhibitors (Non-Nucleoside). Reverse Transcriptase Inhibitors (Non-Nucleoside) may decrease serum concentration of Reverse Transcriptase Inhibitors (Non-Nucleoside). Specifically, efavirenz and nevirapine may decrease the serum concentrations of other non-nucleoside reverse transcriptase inhibitors. Reverse Transcriptase Inhibitors (Non-Nucleoside) may increase serum concentration of Reverse Transcriptase Inhibitors (Non-Nucleoside). Specifically, delavirdine may increase the serum concentration of etravirine. Risk X: Avoid
Revumenib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Revumenib. Risk X: Avoid
Ribociclib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ribociclib. Risk C: Monitor
Rifabutin: Efavirenz may decrease serum concentration of Rifabutin. Rifabutin may decrease serum concentration of Efavirenz. Management: If efavirenz is to be used with daily rifabutin, increase the planned rifabutin dose by 50% to a dose of 450 mg to 600 mg daily. If used with regimens where rifabutin is administered 2 to 3 times per week, consider doubling the rifabutin dose. Risk D: Consider Therapy Modification
RifAMPin: May decrease serum concentration of Efavirenz. Efavirenz may decrease serum concentration of RifAMPin. Management: Monitor for reduced response to efavirenz and rifampin. Guidelines suggest no efavirenz dose adjustments are required when combined, while labeling recommends an efavirenz dose increase to 800 mg daily in adults weighing more than 50 kg. Risk C: Monitor
Rimegepant: CYP3A4 Inducers (Moderate) may decrease serum concentration of Rimegepant. Risk X: Avoid
Ripretinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ripretinib. Management: Avoid this combination if possible. If concomitant use is required, increase ripretinib to 150 mg twice daily. Decrease ripretinib to 150 mg once daily 14 days after stopping a moderate CYP3A4 inducer. Monitor patients for ripretinib response and toxicity Risk D: Consider Therapy Modification
RisperiDONE: CYP3A4 Inducers (Moderate) may decrease serum concentration of RisperiDONE. CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of RisperiDONE. Risk C: Monitor
Ritlecitinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ritlecitinib. Risk C: Monitor
Ritonavir: Efavirenz may increase adverse/toxic effects of Ritonavir. Efavirenz may increase serum concentration of Ritonavir. Ritonavir may increase serum concentration of Efavirenz. Risk C: Monitor
Roflumilast (Systemic): CYP3A4 Inducers (Moderate) may decrease serum concentration of Roflumilast (Systemic). CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Roflumilast (Systemic). Risk C: Monitor
Rolapitant: CYP3A4 Inducers (Moderate) may decrease serum concentration of Rolapitant. Risk C: Monitor
Sacituzumab Govitecan: UGT1A1 Inducers may decrease active metabolite exposure of Sacituzumab Govitecan. Specifically, concentrations of SN-38 may be decreased. Risk X: Avoid
Samidorphan: CYP3A4 Inducers (Moderate) may decrease serum concentration of Samidorphan. Risk C: Monitor
Saquinavir: May increase hepatotoxic effects of Efavirenz. Efavirenz may decrease serum concentration of Saquinavir. Management: When used together with efavirenz, saquinavir should not be used as the sole protease inhibitor. Appropriate doses of the combination of efavirenz with saquinavir/ritonavir have not been established. Risk X: Avoid
Selpercatinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Selpercatinib. Risk X: Avoid
Selumetinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Selumetinib. Risk X: Avoid
Sertraline: CYP3A4 Inducers (Moderate) may decrease serum concentration of Sertraline. Risk C: Monitor
Sildenafil: CYP3A4 Inducers (Moderate) may decrease serum concentration of Sildenafil. Risk C: Monitor
Simeprevir: CYP3A4 Inducers (Moderate) may decrease serum concentration of Simeprevir. Risk X: Avoid
Simvastatin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Simvastatin. Risk C: Monitor
Sirolimus (Conventional): CYP3A4 Inducers (Moderate) may decrease serum concentration of Sirolimus (Conventional). Risk C: Monitor
Sirolimus (Protein Bound): CYP3A4 Inducers (Moderate) may decrease serum concentration of Sirolimus (Protein Bound). Risk C: Monitor
Sonidegib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Sonidegib. Risk X: Avoid
SORAfenib: CYP3A4 Inducers (Moderate) may decrease serum concentration of SORAfenib. Risk C: Monitor
Sotorasib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Sotorasib. Risk C: Monitor
Sparsentan: CYP3A4 Inducers (Moderate) may decrease serum concentration of Sparsentan. Risk C: Monitor
SUFentanil: CYP3A4 Inducers (Moderate) may decrease serum concentration of SUFentanil. Risk C: Monitor
SUNItinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of SUNItinib. Risk C: Monitor
Suvorexant: CYP3A4 Inducers (Moderate) may decrease serum concentration of Suvorexant. Risk C: Monitor
Suzetrigine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Suzetrigine. Risk X: Avoid
Tacrolimus (Systemic): CYP3A4 Inducers (Moderate) may decrease serum concentration of Tacrolimus (Systemic). Risk C: Monitor
Tadalafil: CYP3A4 Inducers (Moderate) may decrease serum concentration of Tadalafil. Risk C: Monitor
Tamoxifen: CYP3A4 Inducers (Moderate) may decrease serum concentration of Tamoxifen. CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Tamoxifen. Risk C: Monitor
Tasimelteon: CYP3A4 Inducers (Moderate) may decrease serum concentration of Tasimelteon. Risk C: Monitor
Tazemetostat: CYP3A4 Inducers (Moderate) may decrease serum concentration of Tazemetostat. Risk X: Avoid
Temsirolimus: CYP3A4 Inducers (Moderate) may decrease serum concentration of Temsirolimus. CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Temsirolimus. Specifically, sirolimus concentrations may be decreased. Risk C: Monitor
Teniposide: CYP3A4 Inducers (Moderate) may decrease serum concentration of Teniposide. Risk C: Monitor
Tetrahydrocannabinol and Cannabidiol: CYP3A4 Inducers (Moderate) may decrease serum concentration of Tetrahydrocannabinol and Cannabidiol. Risk C: Monitor
Tetrahydrocannabinol: CYP3A4 Inducers (Moderate) may decrease serum concentration of Tetrahydrocannabinol. Risk C: Monitor
Tezacaftor and Ivacaftor: CYP3A4 Inducers (Moderate) may decrease serum concentration of Tezacaftor and Ivacaftor. Risk C: Monitor
Thiotepa: CYP3A4 Inducers (Moderate) may increase active metabolite exposure of Thiotepa. CYP3A4 Inducers (Moderate) may decrease serum concentration of Thiotepa. Risk C: Monitor
Thiotepa: May increase serum concentration of CYP2B6 Substrates (High risk with Inhibitors). Risk C: Monitor
Ticagrelor: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ticagrelor. CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Ticagrelor. Risk C: Monitor
Tivozanib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Tivozanib. Risk C: Monitor
Tofacitinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Tofacitinib. Risk C: Monitor
Tolvaptan: CYP3A4 Inducers (Moderate) may decrease serum concentration of Tolvaptan. Risk C: Monitor
Toremifene: CYP3A4 Inducers (Moderate) may decrease serum concentration of Toremifene. CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Toremifene. Risk C: Monitor
Trabectedin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Trabectedin. Risk C: Monitor
TraMADol: CYP3A4 Inducers (Moderate) may decrease serum concentration of TraMADol. Risk C: Monitor
TraZODone: CYP3A4 Inducers (Moderate) may decrease serum concentration of TraZODone. Risk C: Monitor
Tretinoin (Systemic): CYP3A4 Inducers (Moderate) may decrease serum concentration of Tretinoin (Systemic). Risk C: Monitor
Triazolam: CYP3A4 Inducers (Moderate) may decrease serum concentration of Triazolam. Risk C: Monitor
Tucatinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Tucatinib. Risk C: Monitor
Ubrogepant: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ubrogepant. Management: Use an initial ubrogepant dose of 100 mg and second dose (if needed) of 100 mg when used with a moderate CYP3A4 inducer. Risk D: Consider Therapy Modification
Ulipristal: CYP3A4 Inducers (Moderate) may decrease serum concentration of Ulipristal. Risk X: Avoid
Upadacitinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Upadacitinib. Risk C: Monitor
Valbenazine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Valbenazine. CYP3A4 Inducers (Moderate) may decrease active metabolite exposure of Valbenazine. Risk C: Monitor
Valoctocogene Roxaparvovec: May increase hepatotoxic effects of Efavirenz. Efavirenz may decrease therapeutic effects of Valoctocogene Roxaparvovec. Risk X: Avoid
Vandetanib: CYP3A4 Inducers (Moderate) may increase active metabolite exposure of Vandetanib. CYP3A4 Inducers (Moderate) may decrease serum concentration of Vandetanib. Risk C: Monitor
Vanzacaftor, Tezacaftor, and Deutivacaftor: CYP3A4 Inducers (Moderate) may decrease serum concentration of Vanzacaftor, Tezacaftor, and Deutivacaftor. Risk X: Avoid
Velpatasvir: CYP2B6 Inducers (Moderate) may decrease serum concentration of Velpatasvir. Risk X: Avoid
Velpatasvir: CYP3A4 Inducers (Moderate) may decrease serum concentration of Velpatasvir. Risk X: Avoid
Vemurafenib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Vemurafenib. Risk C: Monitor
Venetoclax: CYP3A4 Inducers (Moderate) may decrease serum concentration of Venetoclax. Risk X: Avoid
Verapamil: CYP3A4 Inducers (Moderate) may decrease serum concentration of Verapamil. Risk C: Monitor
Vilazodone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Vilazodone. Risk C: Monitor
VinCRIStine: CYP3A4 Inducers (Moderate) may decrease serum concentration of VinCRIStine. Risk C: Monitor
Vitamin K Antagonists: Efavirenz may decrease serum concentration of Vitamin K Antagonists. Efavirenz may increase serum concentration of Vitamin K Antagonists. Risk C: Monitor
Voclosporin: CYP3A4 Inducers (Moderate) may decrease serum concentration of Voclosporin. Risk X: Avoid
Vonoprazan: CYP3A4 Inducers (Moderate) may decrease serum concentration of Vonoprazan. Risk X: Avoid
Vorapaxar: CYP3A4 Inducers (Moderate) may decrease serum concentration of Vorapaxar. Risk X: Avoid
Voriconazole: Efavirenz may decrease serum concentration of Voriconazole. Voriconazole may increase serum concentration of Efavirenz. Management: Use of standard doses of these drugs is contraindicated. The voriconazole oral maintenance dose should be increased to 400 mg every 12 hours, and the efavirenz dose should be reduced to 300 mg daily. Risk D: Consider Therapy Modification
Vortioxetine: CYP3A4 Inducers (Moderate) may decrease serum concentration of Vortioxetine. Risk C: Monitor
Voxelotor: CYP3A4 Inducers (Moderate) may decrease serum concentration of Voxelotor. Management: Avoid concomitant use of voxelotor and moderate CYP3A4 inducers. If unavoidable, increase the voxelotor dose to 2,000 mg once daily. For children ages 4 to less than 12 years, weight-based dose adjustments are required. See full monograph for details. Risk D: Consider Therapy Modification
Voxilaprevir: CYP3A4 Inducers (Moderate) may decrease serum concentration of Voxilaprevir. Risk X: Avoid
Zaleplon: CYP3A4 Inducers (Moderate) may decrease serum concentration of Zaleplon. Risk C: Monitor
Zanubrutinib: CYP3A4 Inducers (Moderate) may decrease serum concentration of Zanubrutinib. Management: Avoid this combination if possible. If coadministration of zanubrutinib and a moderate CYP3A4 inducer is required, increase the zanubrutinib dose to 320 mg twice daily. Risk D: Consider Therapy Modification
Zolpidem: CYP3A4 Inducers (Moderate) may decrease serum concentration of Zolpidem. Risk C: Monitor
Zopiclone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Zopiclone. Risk C: Monitor
Zuranolone: CYP3A4 Inducers (Moderate) may decrease serum concentration of Zuranolone. Risk X: Avoid
High-fat/high-caloric meals increase the absorption of efavirenz. CNS effects are possible. Management: Avoid high-fat/high-caloric meals. Administer at or before bedtime on an empty stomach unless using capsule sprinkle method in patients unable to swallow capsules or tablets. If capsule sprinkle method is used, patient should not consume additional food for 2 hours after administration.
Pregnancy testing is recommended by the manufacturer prior to initiating efavirenz in patients who could become pregnant. Barrier contraception in combination with other (hormonal) methods of contraception during therapy and for 12 weeks after efavirenz is discontinued is also recommended by the manufacturer. However, available guidelines do not restrict the use of efavirenz in patients who are planning to become pregnant and note contraception is not required to initiate or continue antiretroviral therapy (ART). Patients with HIV who may become pregnant but who are not planning a pregnancy may use any available type of contraception, considering possible drug interactions and contraindications of the specific method. Consult drug interactions database for more detailed information specific to use of efavirenz and specific contraceptives, particularly if efficacy of the contraceptive method is of primary importance (HHS [perinatal] 2024).
Efavirenz is an alternative ART for patients with HIV who are not yet pregnant but are trying to conceive.
Maximum viral suppression sustained below the limits of detection prior to conception is recommended for all persons with HIV who are planning a pregnancy. Prior to pregnancy, select or make changes to a specific antiretroviral regimen as part of a shared decision-making process. In most cases, recommendations based on data obtained from cisgender women can be applied to transgender and gender diverse people assigned female sex at birth.
Health care providers caring for couples planning a pregnancy when one or both partners are diagnosed with HIV may contact the National Perinatal HIV Hotline (1-888-448-8765) for clinical consultation (HHS [perinatal] 2024).
Efavirenz has a moderate level of transfer across the human placenta.
Based on data from the Antiretroviral Pregnancy Registry, an increased risk of overall teratogenic effects has not been observed following first trimester exposure to efavirenz. Neural tube and other CNS defects have been reported; however, data collected by the registry has shown that the risk for neural tube defects after efavirenz exposure in the first trimester are not greater than those in the general population. Additional data are needed to evaluate the potential risks of microcephaly and developmental delay. Maternal antiretroviral therapy (ART) may be associated with adverse pregnancy outcomes including preterm birth, low birth weight, and small for gestational age infants. High viral loads are also associated with adverse outcomes, including preterm birth and pregnancy loss. Treatment improves the health of the pregnant patient and reduces the risk of perinatal transmission. Do not withhold appropriate maternal ART due to concerns for adverse neonatal outcomes. Closely monitor for pregnancy complications. Document in utero ART exposure in the long-term medical record of a child born without HIV; evaluate for potential metabolic dysfunction if significant organ system abnormalities of unknown etiology (particularly of the CNS or heart) develop.
Efavirenz is an alternative ART for pregnant patients with HIV who are antiretroviral-naive, who have had ART therapy in the past but are restarting, or who require a new ART regimen (due to poor tolerance or poor virologic response of current regimen). Patients who become pregnant while taking efavirenz may continue if viral suppression is effective and the regimen is well tolerated.
The pharmacokinetics of efavirenz may be altered in pregnancy, particularly during the third trimester in patients who are extensive CYP2B6 metabolizers. The standard adult doses should be used until pharmacokinetic data are available for the use of reduced doses in patients who are pregnant.
Use may be considered for patients having drug interactions with other medications or who require the convenience of once daily dosing (and are not eligible for dolutegravir); screening for antenatal and postpartum depression is recommended. Although not recommended by the manufacturer, available guidelines do not restrict the use of efavirenz in the first trimester.
ART is recommended for all pregnant people with HIV to maximize their health, maintain the viral load below the limit of an ultrasensitive assay detection, and reduce the risk of perinatal transmission. Start ART prior to conception or as soon as possible during pregnancy. During pregnancy, select or make changes to a specific antiretroviral regimen as part of a shared decision-making process. Patients on fully suppressive regimens prior to pregnancy generally may continue the same regimen considering known pregnancy outcomes and pharmacokinetic data. Monitor pregnant patients more frequently than nonpregnant patients. ART initiated during pregnancy can be modified after delivery. In most cases, recommendations based on data obtained from cisgender women can be applied to transgender and gender diverse people assigned female sex at birth.
Data collection to monitor pregnancy and infant outcomes following exposure to ART is ongoing. Enroll all patients exposed to antiretroviral medications as early in pregnancy as possible in the Antiretroviral Pregnancy Registry (1-800-258-4263).
Health care providers caring for pregnant patients with HIV infection and their infants may contact the National Perinatal HIV Hotline (1-888-448-8765) for clinical consultation (HHS [perinatal] 2024).
Efavirenz is present in breast milk.
Plasma concentrations of efavirenz in breastfeeding infants have been reported as ~13% of maternal plasma concentrations. Infants in this study (n=13) were exposed to efavirenz during the last trimester of pregnancy and 6 months postpartum.
Provide patient-centered evidence-based counseling for infant feeding options as early as possible in pregnancy.
• Using properly prepared formula or pasteurized banked donor milk eliminates the risk of postnatal HIV transmission via breastfeeding.
• Counsel patients on antiretroviral therapy (ART) who achieve and maintain a consistently undetectable plasma viral load during pregnancy and postnatally about feeding options, including breastfeeding, formula feeding, or banked donor milk. Maintaining maximum viral suppression decreases but does not eliminate the risk of HIV transmission via breast milk. Temporary discontinuation of breastfeeding and use of replacement feeding may be required if maternal viral load becomes detectable or if mastitis or bleeding nipples develop. Permanent discontinuation of breastfeeding is recommended if the maternal HIV RNA is ≥200 copies/mL.
• Formula feeding or banked donor milk is recommended for persons with HIV who are not on ART and/or do not have sustained viral suppression. Provide the infant presumptive ART throughout breastfeeding and for up to 6 weeks after the last exposure to breast milk if the breastfeeding parent does not have sustained viral suppression but breastfeeding is continued; conduct infant virologic diagnostic testing at specified intervals.
• When the HIV status at delivery is not known, breast milk may be expressed and stored until a negative test is available.
• Discontinue breastfeeding immediately if HIV infection is diagnosed after breastfeeding has been initiated.
• Evaluate and provide support for maternal conditions that would make adherence to postpartum ART difficult.
Information is available for counseling and managing patients with HIV who are considering breastfeeding (1-888-448-8765). In most cases, recommendations based on data obtained from cisgender women can be applied to transgender and gender diverse people assigned female sex at birth (HHS [perinatal] 2024).
Should be taken on an empty stomach unless using capsule sprinkle method in patients unable to swallow capsules or tablets. If capsule sprinkle method is used, do not consume additional food for 2 hours after administration.
Serum transaminases; cholesterol and triglycerides (prior to therapy and periodically during); signs and symptoms of infection; psychiatric effects
As a non-nucleoside reverse transcriptase inhibitor, efavirenz has activity against HIV-1 by binding to reverse transcriptase. It consequently blocks the RNA-dependent and DNA-dependent DNA polymerase activities including HIV-1 replication. It does not require intracellular phosphorylation for antiviral activity.
Absorption: Increased by high-fat/high-caloric meals
Distribution: CSF concentrations are 0.69% of plasma (range: 0.26% to 1.2%); however, CSF:plasma concentration ratio is 3 times higher than free fraction in plasma
Protein binding: >99%, primarily to albumin
Metabolism: Hepatic via CYP3A and 2B6 to inactive hydroxylated metabolites which then undergo glucuronidation; induces P450 enzymes and its own metabolism
Bioavailability: 42%
Half-life elimination: Single dose: 52 to 76 hours; Multiple doses: 40 to 55 hours
Time to peak: 3 to 5 hours
Excretion: Feces (16% to 61% primarily as unchanged drug); urine (~14% to 34% as metabolites; <1% unchanged drug)
