efavirenz at a glance
Medicine class
Non-nucleoside reverse transcriptase inhibitor (NNRTI) antiretroviral.
Main use
Combination treatment of HIV-1 infection.
Food
Take on an empty stomach because food can increase exposure and adverse effects.
Driving
Do not drive or operate machinery if dizziness, drowsiness or poor concentration occurs.
What is efavirenz used for?
Efavirenz is licensed as part of combination antiviral treatment for HIV-1 infection.
It is used in adults, adolescents and eligible children alongside other antiretrovirals.
It must not be used alone or added as the only new treatment to a failing HIV regimen because resistance can emerge rapidly.
How does efavirenz work?
Efavirenz binds to HIV-1 reverse transcriptase and changes how the enzyme works, limiting the virus’s ability to copy its genetic material and reproduce.
efavirenz preparations and strengths
Tablet
Route: Oral
Strengths: 600 mg
How to take efavirenz
Follow instructions from the specialist HIV team.
Swallow the selected tablet whole with water.
Take it on an empty stomach. Bedtime administration may make dizziness or drowsiness less troublesome.
Avoid grapefruit juice.
Do not stop efavirenz or alter accompanying antiretrovirals without specialist advice.
efavirenz side effects
Common or expected effects
- Rash or itching
- Dizziness, drowsiness, headache or impaired concentration
- Abnormal dreams, insomnia, anxiety or low mood
- Nausea, vomiting, diarrhoea or abdominal pain
- Tiredness
- Raised liver enzymes or blood triglycerides
Get urgent medical advice
- Blistering, peeling or widespread rash, especially with fever or mouth, eye or genital sores
- Severe allergic reaction with swelling or breathing difficulty
- Severe depression, suicidal thoughts, psychosis, hallucinations or marked behavioural change
- Seizures
- Severe unsteadiness, confusion, slowed thinking or reduced consciousness
- Symptoms suggesting serious liver injury
efavirenz in pregnancy
The selected product information says efavirenz should be used during pregnancy only when clinically required and advises pregnancy testing and effective contraception around treatment. Contact the specialist HIV team promptly if pregnant, planning pregnancy or becoming pregnant. Do not stop antiretroviral treatment without advice.
efavirenz while breastfeeding
Efavirenz enters human milk, and the selected product information advises against breastfeeding during treatment. NHS information describes formula feeding as safest for people living with HIV, although supported breastfeeding may sometimes be considered when viral load is undetectable. Discuss feeding with the specialist HIV and maternity team.
efavirenz interactions
Efavirenz affects several drug-metabolising enzymes. Ask the HIV team to check all prescribed, pharmacy and herbal products.
St John’s wort
Contraindicated because it can lower efavirenz concentrations and reduce antiviral effect.
Hormonal contraceptives
Efavirenz can reduce exposure to some hormonal contraceptives; the product information advises additional reliable barrier contraception.
Medicines that prolong the QT interval
Some antiarrhythmics, antipsychotics, antidepressants, antimicrobials and methadone can increase the risk of serious abnormal heart rhythms and may be contraindicated.
Common questions about efavirenz
Answers are fully visible for fast scanning and source review.
Can efavirenz cure HIV?
No. It suppresses HIV replication as part of combination treatment but does not remove HIV from the body.
Can efavirenz be taken by itself?
No. Using it alone can allow resistant HIV to emerge rapidly.
Should efavirenz be taken with food?
The selected tablet should be taken on an empty stomach because food can increase exposure and adverse effects.
Do efavirenz side effects improve over time?
Dizziness, sleep disturbance and other nervous-system effects often begin early and commonly improve within the first few weeks. Persistent or severe symptoms need review.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.