HIV Pre-Exposure Prophylaxis (PrEP) Recommendations
Tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) 300mg/200mg taken once daily is the recommended PrEP regimen for all populations at risk of HIV acquisition. 1, 2
Standard Dosing Regimens by Population
For Men Who Have Sex with Men (MSM)
- Initiate with a double dose (2 tablets) on day 1, then continue once daily thereafter to achieve maximal protection within 24 hours 1
- Maximum protection is achieved within 24 hours of the double-dose initiation 1
- When stopping PrEP, continue for 2 days after the last at-risk exposure 1
- Alternative on-demand "2-1-1" dosing is acceptable for MSM only: 2 tablets taken 2-24 hours before sex, 1 tablet 24 hours later, and 1 tablet 48 hours after the first dose 1, 3
- Continue daily dosing until 48 hours after last sexual contact when using on-demand dosing 1
For All Other Populations (Women, Heterosexual Men, People Who Inject Drugs)
- Take once daily without loading dose 1, 4
- Maximum protection requires approximately 7 days of daily dosing 1
- When stopping PrEP, continue for 7 days after the last at-risk exposure 1
- Daily dosing is critical for women because tenofovir concentrates at 10-fold lower levels in vaginal tissue compared to rectal tissue, with faster clearance 4, 5
Special Populations
- Pregnant and breastfeeding individuals: Daily TDF/FTC is recommended and safe with no documented adverse fetal effects 1, 2
- MSM with creatinine clearance 30-60 mL/min or osteopenia/osteoporosis: Consider tenofovir alafenamide/emtricitabine (TAF/FTC) instead of TDF/FTC 1, 2
Pre-Initiation Testing Requirements
Before prescribing PrEP, obtain the following tests 4, 2:
- Combined HIV antibody and antigen testing (to rule out acute HIV)
- Serum creatinine and estimated creatinine clearance
- Hepatitis B surface antigen (HBsAg)
- Hepatitis C antibody
- Nucleic acid amplification testing (NAAT) for gonorrhea and chlamydia (genital and non-genital sites)
- Syphilis testing
- Pregnancy test for individuals of childbearing potential
Monitoring Schedule During PrEP Use
Every 3 Months 4, 2
- Combined HIV antibody/antigen testing
- STI screening (gonorrhea, chlamydia, syphilis)
- Pregnancy testing for individuals of childbearing potential
- Estimated creatinine clearance
Additional Monitoring 2
- HIV testing at 1 month after initiation (then quarterly)
- More frequent renal monitoring if baseline creatinine clearance <90 mL/min or if patient has diabetes or hypertension
Critical caveat: PrEP prescriptions should not exceed 90 days without interval HIV testing to avoid inadvertently treating undiagnosed HIV infection with suboptimal therapy 4
Who Should Receive PrEP
PrEP should be discussed with all sexually active adults and adolescents and individuals who inject drugs 1
High-Risk Populations Include 1, 2:
- MSM with condomless anal intercourse, multiple partners, or HIV-positive partner(s)
- Transgender individuals engaging in condomless sex or with multiple partners
- Heterosexual individuals with HIV-positive sexual partners or inconsistent condom use with partners of unknown status
- Individuals from locations where HIV incidence ≥2-3% per year
- Individuals with recent bacterial STI diagnosis
- People who inject drugs and share needles or equipment
- Individuals who have traded sex for money, goods, or services
Efficacy and Adherence
PrEP efficacy exceeds 90% when adherence is maintained with detectable drug levels 2, 6, 7. However, efficacy is highly adherence-dependent, dropping to 44% with suboptimal adherence versus 92% with detectable drug levels 2, 6. In real-world cohorts with good adherence, HIV incidence was as low as 0.82 per 100 person-years 3.
Important Clinical Caveats
- PrEP does not prevent other sexually transmitted infections—condoms remain recommended for STI prevention 1, 4
- Common adverse events include nausea, elevated creatinine, and decreased bone mineral density, but these are generally manageable with monitoring 7
- For hepatitis B surface antigen-positive individuals: Consider indefinite continuation or transition to hepatitis B treatment if stopping PrEP, as discontinuation can cause hepatitis flares 2
- Enhanced adherence counseling is essential, particularly for adolescents and women, given the adherence-dependent efficacy 2