Efavirenz
Pronunciation: eh-FAH-vih-renz.
- Generic name
- efavirenz
- Brand names
- Sustiva, Efamat, Efcure, Atripla (combination), Stocrin, Efavir
- Drug class
- Non-nucleoside reverse transcriptase inhibitor (NNRTI)
Availability and supply rules vary by country
Trade names by country: Canada
Australia: · Full directory
What efavirenz is and how it works
Uses, formulations, monitoring, and supply rules can differ by patient, product, and country. Follow the exact local product information and professional advice.
Mechanism of action: how efavirenz works
Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI). It binds directly to the reverse transcriptase enzyme of HIV-1, causing a conformational change that inhibits the enzyme's activity. This prevents the conversion of viral RNA into DNA, thereby blocking HIV replication. (1)
What efavirenz is used for
HIV infection
Used, in combination with other antiretroviral agents, for the treatment of HIV-1 infection in adults and children aged 3 years and older; it is not a cure but helps control viral replication and reduce the risk of HIV-related complications. (2)
Before taking efavirenz
Do not take / not appropriate for
- Contraindicated in patients with hypersensitivity to efavirenz or any component of the formulation. (Contraindication) (2)
- Avoid use with drugs highly dependent on CYP3A4 for clearance (e.g., midazolam, triazolam, ergot derivatives). (Contraindication) (2)
- Efavirenz may cause fetal harm. (Contraindication) (2)
- avoid in pregnancy unless benefits outweigh risks. (Contraindication) (2)
Tell your clinician about
(2)How to take efavirenz
- General Instructions: Take efavirenz exactly as prescribed, once daily, preferably at bedtime to minimize side effects. Do not skip doses or stop taking the medication without consulting your doctor.. Adult Dosing: The usual adult dose is 600 mg once daily, taken on an empty stomach, preferably at bedtime.. Pediatric Dosing: Dosing in children is based on weight and age. Consult a pediatric HIV specialist for appropriate dosing.. Administration: Swallow tablets or capsules whole with water. Take on an empty stomach (1 hour before or 2 hours after a meal) to reduce side effects.. When To Stop: Do not stop taking efavirenz unless instructed by your healthcare provider. Stopping can lead to drug resistance and treatment failure.. Storage: Store at room temperature (68–77°F or 20–25°C), away from moisture and heat. Keep out of reach of children.
- This page does not provide a dose calculator. Dosing must follow the prescriber, pharmacist, or product label.
Procedures and treatment changes
Tell the treating team before surgery, procedures, or any medicine change. Do not alter treatment without the responsible clinician. (2)
Missed dose
If you miss a dose, take it as soon as you remember. If it is almost time for your next dose, skip the missed dose and resume your regular schedule. Do not take two doses at once.
Overdose
In case of overdose, seek emergency medical attention or contact a poison control center immediately. Symptoms may include confusion, dizziness, agitation, or seizures. Supportive care is the mainstay of treatment. (2)
Side effects
Side effects and their urgency vary; report severe, persistent, or concerning symptoms to a healthcare professional.
Dizziness
Incidence: Reported in the clinician-authored database; frequency not established
Rash
Incidence: Reported in the clinician-authored database; frequency not established
Abnormal dreams
Incidence: Reported in the clinician-authored database; frequency not established
Nausea
Incidence: Reported in the clinician-authored database; frequency not established
Diarrhea
Incidence: Reported in the clinician-authored database; frequency not established
Depression
Incidence: Reported in the clinician-authored database; frequency not established
Insomnia
Incidence: Reported in the clinician-authored database; frequency not established
Hepatotoxicity
Incidence: Reported in the clinician-authored database; frequency not established
Headache
Incidence: Common (>5%, moderate-to-severe intensity, per FDA label)
Fatigue
Incidence: Common (>5%, moderate-to-severe intensity, per FDA label)
Vomiting
Incidence: Common (>5%, moderate-to-severe intensity, per FDA label)
Nervous system symptoms (dizziness, trouble concentrating, sleepiness) considered together
Incidence: Approximately 53% of patients in clinical trials; typically resolve within 2-4 weeks of continued treatment
Severe depression (reported in about 2.4% of patients), suicidal thoughts (about 0.7%), or aggressive behavior (about 0.4%)
Incidence: Uncommon but serious; seek prompt medical evaluation
Signs of severe skin reaction (widespread rash, blistering, peeling skin) or signs of liver problems (yellowing skin/eyes, dark urine, severe fatigue)
Incidence: Uncommon but serious
Serious warnings
Efavirenz can cause serious psychiatric symptoms, including depression, suicidal thoughts, and aggressive behavior — serious
Symptoms: Efavirenz can cause serious psychiatric symptoms, including depression, suicidal thoughts, and aggressive behavior. May cause serious liver problems; monitor for signs of hepatitis or jaundice. Can cause severe rash, sometimes with blistering or peeling. May cause birth defects; avoid use in pregnancy unless no alternatives are available. Efavirenz interacts with many medications; inform your doctor of all medicines you take.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)
Contraindicated in patients with hypersensitivity to efavirenz or any component of the formulation, including a prior history of Stevens-Johnson syndrome, erythema multiforme, or toxic skin eruptions with this medicine — serious
Symptoms: Contraindicated in patients with hypersensitivity to efavirenz or any component of the formulation, including a prior history of Stevens-Johnson syndrome, erythema multiforme, or toxic skin eruptions with this medicine. Co-administration is contraindicated with ergot derivatives, midazolam, triazolam, bepridil, cisapride, pimozide, and St. John's wort. Use caution in patients with psychiatric illness, liver disease, or a history of seizures. Efavirenz may cause fetal harm; avoid in pregnancy unless benefits outweigh risks.
Action: Follow the urgency stated and seek prompt or emergency care when indicated. (2)
Interactions
| Medicine or test | Effect | Action |
|---|---|---|
| Recorded interactions | Efavirenz interacts with many drugs, including certain antiretrovirals, anticonvulsants, antifungals, hormonal contraceptives, and herbal supplements like St. John's wort. These interactions may increase side effects or reduce the effectiveness of efavirenz or other medicines. Always inform your healthcare provider about all medications and supplements you are taking. | (1) |
| Voriconazole and rifampin (dose-adjustment interactions) | When co-administered with voriconazole, efavirenz is typically reduced to 300 mg daily (capsule formulation) with the voriconazole dose increased; when co-administered with rifampin, efavirenz is typically increased to 800 mg daily in patients weighing 50 kg or more. These adjustments are made and monitored by the prescribing clinician, not by the patient. | (2) |
Pregnancy, breastfeeding, kidney/liver function, age
Pregnancy
FDA Pregnancy Category D: efavirenz may cause fetal harm when taken during the first trimester. Women of childbearing potential are generally advised to avoid becoming pregnant while taking efavirenz and for 12 weeks after stopping it, and to use effective contraception (barrier method plus another method) during this time. An Antiretroviral Pregnancy Registry monitors outcomes in women exposed to efavirenz during pregnancy. Any pregnancy, or plan to become pregnant, should be discussed promptly with the treating HIV clinician, who will weigh individual risks and benefits. (2)
Breastfeeding
Women with HIV are generally instructed not to breastfeed while taking efavirenz, because of the risk of postnatal HIV transmission through breast milk and the potential for adverse effects in the nursing infant. Infant feeding plans should be discussed with the treating clinician. (2)
Children
Frequency: Not applicable. Weight Based: Not recommended for pediatric use; safety and efficacy not established in children under 3 years of age.. Max Daily Dose: Not applicable. Max Single Dose: Not applicable. Age Restrictions: Safety not established in children under 3 years; for children aged 3 years and older, dosing is based on weight. (2)
Renal Impairment
Hepatic impairment: efavirenz is not recommended for patients with moderate or severe hepatic impairment; it should be used with caution, and with closer monitoring, in mild hepatic impairment. Renal impairment: no dose adjustment is needed, because efavirenz undergoes minimal excretion by the kidneys. (2)
Hepatic Impairment
Hepatic impairment: efavirenz is not recommended for patients with moderate or severe hepatic impairment; it should be used with caution, and with closer monitoring, in mild hepatic impairment. Renal impairment: no dose adjustment is needed, because efavirenz undergoes minimal excretion by the kidneys. (2)
Monitoring
(2)Storage
Store at room temperature (68-77°F or 20-25°C), away from moisture and heat. Keep out of reach of children.
Professional information
Clinician-facing context only. This section does not replace current product labeling.
General
Indication: HIV infection
Dose summary: 600 mg orally once daily, preferably at bedtime on an empty stomach.
Renal context: No dose adjustment is needed for renal impairment, because efavirenz undergoes minimal excretion by the kidneys. (1) (2)
Frequently asked questions
What is efavirenz used for?
Efavirenz is used to treat HIV-1 infection in adults and children. It is always used in combination with other antiretroviral medications to help control HIV and improve immune function.
How should I take efavirenz?
Take efavirenz once daily, preferably at bedtime, on an empty stomach. Swallow the tablet or capsule whole with water. Taking it at bedtime may help reduce side effects like dizziness or vivid dreams.
What are the most common side effects?
Common side effects include dizziness, headache, trouble sleeping, unusual dreams, tiredness, and rash. These are usually mild and may improve over time.
Can efavirenz cause mental health problems?
Yes, efavirenz can cause psychiatric symptoms such as depression, anxiety, confusion, or suicidal thoughts. Contact your doctor immediately if you experience any severe mood changes.
Is efavirenz safe in pregnancy?
Efavirenz may cause birth defects if taken during the first trimester of pregnancy. It should be avoided in pregnancy unless no suitable alternatives are available. Discuss family planning and contraception with your doctor.
What should I do if I miss a dose?
Take the missed dose as soon as you remember, unless it is almost time for your next dose. Do not take two doses at once. Continue with your regular dosing schedule.
Can I take efavirenz with other medications?
Efavirenz interacts with many medications, including some antiretrovirals, anticonvulsants, and herbal supplements. Always inform your healthcare provider about all medicines and supplements you are taking.
What happens if I take too much Efavirenz?
Taking too much Efavirenz can lead to an overdose, potentially causing severe central nervous system effects like confusion, hallucinations, and seizures. If you suspect an overdose, it is crucial to seek immediate emergency medical attention. Do not attempt to induce vomiting or self-treat. Contact your local emergency services or poison control center right away.
Can I drink alcohol while taking Efavirenz?
It is generally recommended to avoid or limit alcohol consumption while taking Efavirenz. Alcohol can exacerbate some of the central nervous system side effects of Efavirenz, such as dizziness and drowsiness. Furthermore, both Efavirenz and alcohol are metabolized by the liver, and combining them may increase the risk of liver toxicity. Always consult your healthcare provider for personalized advice.
Is Efavirenz safe during pregnancy?
Efavirenz is classified in Pregnancy Category D, meaning there is positive evidence of human fetal risk, but the benefits from use in pregnant women may be acceptable despite the risk. The decision to use Efavirenz during pregnancy should be made in close consultation with a healthcare provider, weighing the potential risks to the fetus against the benefits of treatment for the mother. Do not make any changes to your medication without medical advice.
What is the mechanism of action of efavirenz?
Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI). It binds directly to the reverse transcriptase enzyme of HIV-1, causing a conformational change that inhibits the enzyme's activity. This prevents the conversion of viral RNA into DNA, thereby blocking HIV replication. (1)
What is the generic name of Efavirenz?
The generic name is efavirenz. It is sold under brand names including Sustiva, Efamat, Efcure, Atripla (combination), Stocrin, Efavir.
What class of drug is efavirenz?
Efavirenz is classed as: Non-nucleoside reverse transcriptase inhibitor (NNRTI).
References
- Efavirenz — MedGuideGlobal medicine recordMedGuideGlobal clinician-authored medicine record (internal database) · Global (curated reference; not a national regulatory authority) · accessed 2026-08-06 · source 1
- SUSTIVA (efavirenz) tablets, film coated — prescribing informationU.S. Food and Drug Administration (DailyMed) · United States · accessed 2026-08-06 · source 2
- EFAVIRENZ, EMTRICITABINE AND TENOFOVIR DISOPROXIL FUMARATE TABLET, FILM COATED [BRYANT RANCH PREPACK] — US prescribing information (DailyMed SPL)U.S. National Library of Medicine (DailyMed) · US · accessed 2026-08-14 · source 3
- Efavirenz — patient drug information (MedlinePlus)U.S. National Library of Medicine (MedlinePlus) · US · accessed 2026-08-14 · source 4
- Efavirenz — FDA approval record (Drugs@FDA ANDA091579)U.S. Food and Drug Administration · US · accessed 2026-08-14 · source 5
- efavirenz — RxNorm normalized drug concept (RXCUI 195085)U.S. National Library of Medicine (RxNorm) · US · accessed 2026-08-14 · source 6
Brand names by country
Single-ingredient efavirenz names are shown separately by country. Product availability, strengths, and supply rules can change; combination products are not included here.
Priority countries
Canada
- SUSTIVA