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NNRTI (antiretroviral)

Efavirenz

Brand names: Sustiva

Efavirenz is a non-nucleoside reverse transcriptase inhibitor (NNRTI) used as part of combination antiretroviral therapy for HIV-1 infection.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It non-competitively inhibits HIV-1 reverse transcriptase, preventing transcription of viral RNA into DNA and thereby suppressing viral replication.

Prescribing in practice

  • Central nervous system and psychiatric effects, including dizziness, abnormal dreams, mood changes, and depression with reports of suicidal ideation, are common and an important safety concern.
  • It is a cytochrome P450 inducer with numerous drug interactions and can prolong the QT interval.
  • It is typically taken once daily at bedtime to reduce the impact of central nervous system side effects, and food can increase exposure.

Monitoring

Monitor HIV viral load and CD4 count for response, alongside mood and neuropsychiatric symptoms and liver function.

Counselling the patient

  • Take at bedtime to lessen dizziness and vivid dreams, which often ease over the first weeks.
  • Report low mood or distressing thoughts promptly.
  • Take consistently every day to keep the virus suppressed.

Evidence & guidelines

Efavirenz has an extensive evidence base from randomised antiretroviral trials and long-standing inclusion in HIV treatment guidelines.

Reference: BHIVA HIV guidelines; EACS; SmPC; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Related

Curated clinical cross-links plus same-class fallbacks.

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