Antiretroviral, non-nucleoside reverse transcriptase inhibitor (NNRTI)
Brand names: Sustiva, Atripla
Updated · Methodology
Second line
Efavirenz is a second-line NNRTI in HIV-1 antiretroviral therapy. GeSIDA 2024 places it as an option when first-line integrase inhibitors are unavailable. Usually taken in the evening before sleep to minimise neuropsychiatric adverse effects. In women of childbearing age – discuss contraception and risk of CNS defects in the first trimester.
Sources
ICD-10: B20 · ICD-11: 1C62
Binds the allosteric pocket of HIV-1 reverse transcriptase and blocks its activity. Not active against HIV-2 or other retroviruses. Strong inducer of CYP3A4 and CYP2B6 (also a CYP2B6 substrate). Reduces levels of most co-administered drugs. Main adverse profile is neuropsychiatric (insomnia, vivid dreams, depression).
Neural tube defects reported with first-trimester exposure. Switch to non-efavirenz regimen when planning pregnancy if possible.
Breastfeeding by HIV-positive women not recommended in Spain.
Reference information, not a clinical decision. Discuss feeding pauses or changes with your physician or an IBCLC.
3 pairs found. Sorted from critical to minor.
Mechanism
St. John's wort is a potent inducer of the CYP3A4 enzyme (and of CYP2C9 and P-glycoprotein). After 1–2 weeks it speeds up the breakdown of Efavirenz and lowers its blood level, weakening its effect.
Symptoms
Fall in antiretroviral levels, loss of HIV virological control and risk of drug resistance.
Management
Contraindicated with antiretroviral therapy. Do not use St. John's wort during HIV treatment.
Mechanism
Efavirenz induces CYP3A4. Simvastatin falls 60% – lipid-lowering effect lost.
Symptoms
returns to baseline.
Management
Alternative statin – pravastatin or rosuvastatin.
Verbatim lines from the interaction sections, in the language of the label
«Established and Other Potentially Significant Drug Interactions: Protease inhibitor: Atazanavir ↓ atazanavir * Treatment –naïve patients : When co-administered with efavirenz tablets , the…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Anti-infective: Clarithromycin ↓ clarithromycin * ↑ 14-OH metabolite * Consider alternatives to macrolide antibiotics because of the…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Itraconazole ↓ itraconazole * ↓ hydroxyitraconazole * Since no dose recommendation for itraconazole can be made, alternative…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Anti-infective: Clarithromycin ↓ clarithromycin * ↑ 14-OH metabolite * Consider alternatives to macrolide antibiotics because of the…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Posaconazole ↓ posaconazole* Avoid concomitant use unless the benefit outweighs the risks.»FDA, section 7 · Open on DailyMed
«QT Prolonging Drugs: There is limited information available on the potential for a pharmacodynamic interaction between efavirenz and drugs that prolong the QTc interval. QTc prolongation has been…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Antimycobacterial: Rifabutin ↓ rifabutin * Increase daily dose of rifabutin by 50%. Consider doubling the rifabutin dose in regimens…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Antifungals: Voriconazole ↓ voriconazole * ↑ efavirenz * Efavirenz and voriconazole should not be co-administered at standard doses…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Phenytoin Phenobarbital ↓ anticonvulsant ↓ efavirenz Potential for reduction in anticonvulsant and/FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Antidepressant: Bupropion Sertraline ↓bupropion* ↓ sertraline * Increases in bupropion dosage should be guided by clinical response…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Others (e.g., felodipine, nicardipine, nifedipine, verapamil) ↓ calcium channel blocker When co-administered with efavirenz, dosage…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Immunosuppressants: Cyclosporine, tacrolimus, sirolimus, and others metabolized by CYP3A ↓ immunosuppressant Dose adjustments of the…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Narcotic analgesic: Methadone ↓ methadone * Monitor for signs of methadone withdrawal and increase methadone dose if required to…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Others (e.g., felodipine, nicardipine, nifedipine, verapamil) ↓ calcium channel blocker When co-administered with efavirenz, dosage…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Phenytoin Phenobarbital ↓ anticonvulsant ↓ efavirenz Potential for reduction in anticonvulsant and/FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Phenytoin Phenobarbital ↓ anticonvulsant ↓ efavirenz Potential for reduction in anticonvulsant and/FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Antidepressant: Bupropion Sertraline ↓bupropion* ↓ sertraline * Increases in bupropion dosage should be guided by clinical response…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Immunosuppressants: Cyclosporine, tacrolimus, sirolimus, and others metabolized by CYP3A ↓ immunosuppressant Dose adjustments of the…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Immunosuppressants: Cyclosporine, tacrolimus, sirolimus, and others metabolized by CYP3A ↓ immunosuppressant Dose adjustments of the…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Others (e.g., felodipine, nicardipine, nifedipine, verapamil) ↓ calcium channel blocker When co-administered with efavirenz, dosage…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Anticoagulant: Warfarin ↑ or ↓ warfarin Monitor INR and adjust warfarin dosage if necessary.»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Drug Interactions: Non-nucleoside Reverse Transcriptase Inhibitors (NNRTIs): efavirenz ↓ atazanavir In HIV-treatment-naive adult patients: If atazanavir…»FDA, section 7 · Open on DailyMed
«DRUG INTERACTIONS: • CYP2B6 inducers: Dose increase may be necessary if coadministered with CYP2B6 inducers (e.g., ritonavir, lopinavir, efavirenz, carbamazepine, phenobarbital, and phenytoin) based…»FDA, section 7 · Open on DailyMed
«DRUG INTERACTIONS: Efavirenz Nevirapine Rifampicin Rifabutin Rifapentine Use With Caution Inducers of CYP3A enzymes, such as efavirenz, nevirapine, rifampicin, rifabutin, and rifapentine will…»FDA, section 7 · Open on DailyMed
«Established and Other Potentially Significant Interactions: efavirenz ↓ cobicistat ↓ darunavir ↓ atazanavir TYBOST coadministered with darunavir: Coadministration of darunavir and TYBOST with…»FDA, section 7 · Open on DailyMed
«Darunavir y cobicistat se metabolizan a través de CYP3A, y la administración de forma conjunta con inductores del CYP3A puede por tanto resultar en una exposición plasmática subterapéutica a…»AEMPS, section 4.5 · Open on CIMA
«CYP3A4 Inhibitors and Inducers: Co-administration of deflazacort with rifampin, a strong CYP3A4 inducer, significantly decreased the exposure of 21-desDFZ. Avoid concomitant use of strong (e.g…»FDA, section 7 · Open on DailyMed
«Tratamiento de larga duración: Sustancias que aumentan el aclaramiento de las hormonas anticonceptivas (disminución de la eficacia anticonceptiva por inducción enzimática), por ejemplo: Barbitúricos…»AEMPS, section 4.5 · Open on CIMA
«Tratamiento de larga duración: Barbitúricos, bosentán, carbamazepina, fenitoína, primidona, rifampicina y los medicamentos para el VIH ritonavir, nevirapina y efavirenz y, también posiblemente…»AEMPS, section 4.5 · Open on CIMA
«Efavirenz: Efavirenz (400 mg una vez al día) disminuyó la C máx y el AUC de posaconazol en un 45 % y un 50 %, respectivamente. Se debe evitar el uso concomitante de posaconazol con efavirenz salvo…»AEMPS, section 4.5 · Open on CIMA
«DRUG INTERACTIONS: Rifabutin, phenytoin, efavirenz Avoid coadministration unless the benefit outweighs the risks ( 7.1 , 7.2 )»FDA, section 7 · Open on DailyMed
«No se recomienda el uso concomitante de acetato de ulipristal con inductores de CYP3A4, debido a las interacciones (por ejemplo, barbitúricos [incluyendo primidona y fenobarbital], fenitoína…»AEMPS, section 4.4 · Open on CIMA
«Efavirenz»AEMPS, section 4.3 · Open on CIMA
«CONTRAINDICATIONS: Coadministration of standard doses of voriconazole with efavirenz doses of 400 mg every 24 hours or higher is contraindicated, because efavirenz significantly decreases plasma…»FDA, section 4 · Open on DailyMed
«Inductores de la CYP3A4: La administración conjunta de atorvastatina con inductores del citocromo P450 3A4 (por ejemplo, efavirenz, rifampicina, hierba de San Juan) puede reducir de forma variable…»AEMPS, section 4.5 · Open on CIMA
«Como bupropión se metaboliza ampliamente, se aconseja tener precaución cuando se administre bupropión concomitantemente con medicamentos de los que se conoce que inducen el metabolismo (p.ej…»AEMPS, section 4.5 · Open on CIMA
«Inducción farmacocinética de enzimas metabolizantes: La administración conjunta de metamizol con bupropión, efavirenz, metadona, valproato, ciclosporina, tacrólimus o sertralina puede disminuir los…»AEMPS, section 4.5 · Open on CIMA
«Antiretroviral Drugs: Loss of virological control has been reported in HIV-infected patients taking orlistat concomitantly with antiretroviral drugs such as atazanavir, ritonavir, tenofovir…»FDA, section 7 · Open on DailyMed
«No se ha evaluado el potencial de inhibición del CYP2B6. Se recomienda prudencia durante la administración concomitante de ranolazina con sustratos del CYP2B6 (p.ej bupropion, efavirenz…»AEMPS, section 4.5 · Open on CIMA
«Dosificación de Ritonavir como potenciador farnacocinético: Atazanavir : No se ha evaluado clínicamente la coadministración de atazanavir y ritonavir a dosis superiores a 100 mg diarios. El uso de…»AEMPS, section 4.4 · Open on CIMA
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Efavirenz is evaluated for the following indications with varying evidence strength: HIV infection (evidence tier B). See the full indication matrix with dosing and citations above on this page.
Common side effects of Efavirenz (≥ 1 in 100): Insomnia, Vivid dreams, Dizziness, Rash, Transaminase rise, Hyperlipidaemia. See the Safety section for uncommon and serious reactions.
Neural tube defects reported with first-trimester exposure. Switch to non-efavirenz regimen when planning pregnancy if possible.
Breastfeeding by HIV-positive women not recommended in Spain.
Efavirenz is contraindicated in: Pimozide, oral midazolam, ergotamine, cisapride; St John's wort (loss of ARV effect); Severe hepatic impairment; Depression with prior suicidal ideation. Full list in the Safety section.
Direct links to regulator labels. Open in a new tab.
Entecavir, Famciclovir, Inosine pranobex, Kagocel, Meglumine acridone acetate, Umifenovir, Aciclovir, Lactoferrin