Recommended Regimen for HIV Pre-Exposure Prophylaxis (PrEP)
Tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) once daily is the recommended oral PrEP regimen for all populations at risk for HIV infection. 1, 2, 3
First-Line PrEP Regimens
- TDF 300mg/FTC 200mg (brand name Truvada) as a single daily oral pill is the standard regimen for all populations at risk for HIV acquisition 1, 3
- For men who have sex with men (MSM), a double dose (2 pills) of TDF/FTC is recommended on the first day of PrEP initiation to achieve protective drug levels more quickly 1, 3
- Daily tenofovir alafenamide/emtricitabine (TAF/FTC) is recommended specifically for MSM with or at risk for kidney dysfunction, osteopenia, or osteoporosis 1, 4
- Event-driven PrEP using the "2-1-1" method (double dose 2-24 hours before sex, then single doses 24 and 48 hours after) is an effective alternative to daily dosing, but only recommended for MSM 1, 5
Population-Specific Considerations
For Women:
- Daily dosing is critical for women as tenofovir concentrates at 10-fold lower levels in vaginal tissue than in rectal tissue 2, 6
- On-demand or event-driven dosing is not recommended for women due to slower drug accumulation in vaginal tissues 2, 6
- TAF/FTC has not been adequately studied for PrEP in women and is not currently recommended 7
For Men Who Have Sex with Men:
- Both daily and on-demand "2-1-1" dosing strategies are effective 1, 5
- TAF/FTC is an alternative for those with renal concerns or bone health issues 4
For People Who Inject Drugs:
- Daily TDF/FTC is the only recommended regimen 3
- Clean injection equipment and access to substance use treatment should be available 2
Pre-Initiation Assessment
Before starting PrEP, the following tests are required:
- Combined HIV antibody and antigen testing (with HIV RNA testing if acute infection is suspected) 1, 3
- Serum creatinine level to evaluate kidney function 1, 3
- Hepatitis B surface antigen testing 1, 3
- Hepatitis C antibody testing 1, 3
- Genital and non-genital testing for sexually transmitted infections 1, 3
- Pregnancy testing for individuals of childbearing potential 2
Monitoring During PrEP Use
- HIV testing should be performed at 1 month after initiation and then every 3 months 1, 3
- STI screening should be conducted every 3 months 1, 2
- Creatinine assessment should be performed every 6 months to monitor kidney function 1, 3
- PrEP prescriptions should not exceed 90 days without interval testing for HIV infection 2
Important Considerations and Potential Pitfalls
- Rule out acute HIV infection before initiating PrEP, especially if there are symptoms consistent with acute HIV infection 1, 3
- PrEP does not protect against other sexually transmitted infections 2
- Adherence is critical for PrEP effectiveness, particularly for women due to pharmacokinetic differences in drug concentration in vaginal versus rectal tissues 6
- Caution is needed when using PrEP in patients with chronic hepatitis B due to risk of hepatitis flares if PrEP is discontinued 3
- TDF/FTC has been shown to be highly effective in multiple clinical trials with risk reduction of 44-75% when used as prescribed 8