Recommended Post-Exposure Prophylaxis (PEP) Dosing Regimen
For HIV post-exposure prophylaxis, the recommended regimen is a 28-day course of a three-drug combination consisting of tenofovir disoproxil fumarate (TDF) plus lamivudine (3TC) or emtricitabine (FTC) as the backbone, with lopinavir/ritonavir (LPV/r) or atazanavir/ritonavir (ATV/r) as the preferred third drug. 1
Basic PEP Regimen Components
Preferred Backbone Regimen
- TDF + 3TC (or FTC) is the recommended backbone regimen for HIV PEP in adults and adolescents 1
- For children ≤10 years, ZDV (zidovudine) + 3TC is the preferred backbone 1
Preferred Third Drug
- LPV/r or ATV/r are suggested as the preferred third drug for adults and adolescents 1
- Alternative options include raltegravir (RAL), darunavir/ritonavir (DRV/r), or efavirenz (EFV) 1
- For children ≤10 years, LPV/r is recommended as the preferred third drug 1
Timing and Duration
- PEP should be initiated as soon as possible after exposure, ideally within 72 hours 1
- The full 28-day course of PEP should be prescribed at the initial assessment 1
- Treatment completion is critical for effectiveness - studies show 86-90% completion rates with newer regimens 2, 3
Alternative Regimens
If the preferred regimens are not available or not tolerated, alternative options include:
- TDF/FTC/rilpivirine (RPV) as a single-tablet regimen, which has shown good tolerability with 86.1% treatment completion rates 2
- Dolutegravir (DTG) with TDF-FTC has demonstrated 90% completion rates with good tolerability 3
Special Considerations
- For pregnant healthcare workers, ZDV + 3TC (Combivir) is considered a safe regimen 1
- For individuals with renal impairment, dose adjustments may be necessary 4
- TAF (tenofovir alafenamide) + FTC may be considered for individuals with creatinine clearance between 30-60 ml/min or with known bone density issues 1, 4
Monitoring and Follow-up
- Evaluate exposed persons taking PEP within 72 hours after exposure 1
- Monitor for drug toxicity for at least 2 weeks 1
- Perform HIV-antibody testing at baseline, 6 weeks, 3 months, and 6 months post-exposure 1
- Advise exposed persons to use precautions to prevent secondary transmission during the follow-up period 1
- Seek immediate medical evaluation for any acute illness occurring during follow-up 1
Common Side Effects and Management
- Common side effects include fatigue (26%), nausea (25%), diarrhea (21%), and headache (10%) 3
- Side effects are generally manageable with antimotility and antiemetic agents 1
- Serious toxicity is rare when used for PEP 1
Historical Context
It's worth noting that older regimens included ZDV + 3TC (Combivir) as the basic regimen 1, but newer combinations have improved tolerability profiles and higher completion rates. The evolution toward three-drug regimens reflects the standard approach used in HIV treatment and provides better coverage against potential drug resistance 1.