Efavirenz

• HIV-1 treatment as part of ART in 2nd/3rd trimester
• Second-line in resource-limited settings

Binds HIV reverse transcriptase at allosteric site → conformational block of polymerase activity.

• Vivid dreams, dizziness — take at bedtime
• Avoid T1 if alternatives — historical NTD signal (now reassured)

Adult

600 mg PO ON (at bedtime)

• CautionT1 — avoid if alternatives exist
• AbsoluteSevere hepatic impairment
• CautionCo-administration with CYP3A4-dependent drugs

• CNS: dizziness, vivid dreams, depression (usually resolves in 2–4 wk)
• Rash (rarely SJS)
• ↑ LFTs
• Dyslipidaemia

• • Earlier NTD signal not replicated in larger human cohorts (WHO 2019)
• • Acceptable if started in T2/T3 or if no alternative
• • Compatible with breastfeeding

• Rifampicin

  Caution

  ↓ efavirenz — increase dose

• Methadone

  Caution

  Withdrawal

• Combined hormonal contraceptives

  Avoid

  ↓ efficacy

• St John's wort

  Avoid

  Treatment failure

• 💡 Switch to dolutegravir preferred when feasible (BHIVA 2023)
• 💡 Counsel: dizziness disappears after ~4 weeks