HIV Post-Exposure Prophylaxis (PEP)

HIV post-exposure prophylaxis (PEP) consists of antiretroviral therapy administered after a potential HIV exposure to prevent infection. Indications include occupational exposures (healthcare workers with needlestick injuries, mucosal splashes from HIV-positive or unknown-status sources), non-occupational exposures (sexual assault, condom failure with HIV-positive partner, sharing of injection equipment, bites with blood exposure), and perinatal exposures.

The standard regimen recommended by CDC and WHO is a three-drug combination: tenofovir disoproxil fumarate (TDF) 300 mg plus emtricitabine (FTC) 200 mg as a fixed-dose combination, plus an integrase inhibitor (dolutegravir 50 mg or raltegravir 400 mg twice daily). Alternative regimens include darunavir/ritonavir-based protease inhibitor combinations for specific clinical scenarios. The duration is 28 days, and PEP must be initiated as soon as possible—ideally within 2 hours, with maximum benefit up to 72 hours; efficacy decreases sharply beyond this window.

Comprehensive post-exposure management includes baseline HIV antibody/antigen testing (HIV-1/2 Ab/Ag combination assay, repeated at 4-6 weeks and 3 months), hepatitis B surface antigen and antibody testing with vaccination/HBIG if indicated, hepatitis C antibody testing, syphilis serology, gonorrhea and chlamydia NAAT, pregnancy testing, and emergency contraception when applicable. Counseling addresses adherence importance, common side effects (nausea, fatigue, headache, diarrhea—usually transient), risk reduction for ongoing exposure, mental health support (especially after sexual assault), and follow-up testing schedule. Failure rate when properly initiated and completed is very low (<1%), but complete failure is documented when source virus has resistance to PEP regimen drugs.