What medications are used in HIV PEP regimens?

HIV Post-Exposure Prophylaxis (PEP) regimens use a combination of three antiretroviral drugs (ARVs) taken daily for 28 days to prevent HIV infection after potential exposure. The choice of regimen depends on availability, patient health status, and drug resistance profiles.

1. Preferred PEP Regimen (CDC and WHO 2025 Guidelines)

For healthy adults and adolescents, the preferred 3-drug regimen includes:

• Tenofovir disoproxil fumarate (TDF) 300 mg
• Emtricitabine (FTC) 200 mg

PLUS one of the following integrase inhibitors:

• Raltegravir (RAL) 400 mg, taken twice daily,
  or
• Dolutegravir (DTG) 50 mg, taken once daily.

This regimen is favored because it is well-tolerated, highly effective, and has minimal drug interactions.

2. Alternative PEP Regimen

If integrase inhibitors are unavailable, an alternative is:

• Tenofovir disoproxil fumarate (TDF) 300 mg
• Emtricitabine (FTC) 200 mg (once daily)
  PLUS
• Darunavir (DRV) 800 mg
• Ritonavir (RTV) 100 mg (both taken once daily)

Ritonavir acts as a pharmacokinetic booster, enhancing the activity and half-life of darunavir.

3. India (NACO) and Low-Resource Settings Regimen

According to the National AIDS Control Organisation (NACO), India, the standard PEP regimen is:

• Tenofovir (TDF) 300 mg
• Lamivudine (3TC) 300 mg
• Efavirenz (EFV) 600 mg, taken once daily for 28 days.

This combination is widely used in healthcare and public health settings for its affordability, simplicity, and single-dose convenience.

4. Special Population Adjustments

• Pregnant or breastfeeding individuals:
  Dolutegravir-based regimens are preferred for their safety and efficacy in pregnancy. Efavirenz-based options remain safe if initiated under medical guidance.
• Children:
  Pediatric formulations use weight-adjusted doses of abacavir + lamivudine + dolutegravir or zidovudine + lamivudine + lopinavir/ritonavir, depending on availability.

5. Medications to Avoid

• Abacavir (ABC) is not recommended in emergency PEP, as HLA-B*5701 hypersensitivity testing cannot be done before immediate initiation.
• Single/dual-drug regimens (older two-drug therapies) are no longer preferred because three-drug combinations have superior viral suppression.