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Efavirenz Gynaecomastia — SCE Infectious Diseases MCQ

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EasyHIV MedicineEfavirenz GynaecomastiaSCE Infectious Diseases

A 40-year-old man with HIV on ART develops gynaec­omastia. His ART regimen is Efavirenz/Tenofovir DF/Emtricitabine. Which component is most likely responsible?

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Correct answer: C — Efavirenz — associated with gynaecomastia, breast hypertrophy, and lipodystrophy; switching to an INSTI-based regimen is recommended

Efavirenz is associated with gynaecomastia (breast enlargement in males) — a well-documented adverse effect occurring in approximately 2–3% of patients. It may be related to Efavirenz-induced changes in oestrogen metabolism. Additionally, Efavirenz is no longer recommended as first-line ART (BHIVA 2025 removed it due to CNS side effects, metabolic effects, and lower genetic barrier to resistance). Switching to an INSTI-based regimen (DTG or BIC) resolves the gynaecomastia in most cases and aligns with current first-line recommendations.

Reference: BHIVA 2025 – ART guidelines; BNF 2024 – Efavirenz