NNRTI (antiretroviral)

Efavirenz

Brand names: Sustiva

Adult dose

Dose: 600mg OD at bedtime

Route: Oral

Frequency: OD nocte

Clinical pearls

Largely superseded by INSTI-based regimens in BHIVA guidelines
Take at bedtime to reduce CNS side effects
HLA-B*5701 not relevant for efavirenz; no allergy testing required

Contraindications

Severe hepatic impairment
Concurrent terfenadine, astemizole, cisapride, ergots, midazolam, triazolam, voriconazole, St John's wort
Hypersensitivity

Side effects

CNS effects (vivid dreams, dizziness, depression, suicidality)
Rash including SJS/TEN
Hepatotoxicity
QT prolongation
Hyperlipidaemia
Gynaecomastia

Interactions

Many CYP-mediated — methadone (withdrawal), warfarin, hormonal contraception (reduced efficacy), statins, voriconazole (avoid), rifampicin

Monitoring

Viral load
CD4
LFTs
Lipids
Mental health
Pregnancy planning

Reference: BNF; BHIVA HIV guidelines; EACS; SmPC; https://bnf.nice.org.uk/drugs/efavirenz/. Verify against your local formulary and the latest BNF before prescribing.

Curated clinical cross-links plus same-class fallbacks.

Calculators

HIV CD4/Viral Load Monitoring Intervals · HIV Management

Drugs

Doravirine · NNRTI (antiretroviral)

Pathways