HIV Pre-Exposure Prophylaxis (PrEP) Medications
The primary FDA-approved HIV PrEP medications are tenofovir disoproxil fumarate/emtricitabine (TDF/FTC), tenofovir alafenamide/emtricitabine (TAF/FTC), and injectable cabotegravir. 1, 2, 3
Oral PrEP Options
First-Line Oral PrEP Medications
- Tenofovir disoproxil fumarate (300mg)/emtricitabine (200mg) (TDF/FTC) - daily oral tablet recommended for all populations at risk for HIV acquisition 1, 2
- Tenofovir alafenamide (25mg)/emtricitabine (200mg) (TAF/FTC) - daily oral tablet recommended specifically for MSM and transgender women, especially those with or at risk for kidney dysfunction, osteopenia, or osteoporosis 1, 2, 4
Dosing Strategies
- For 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 dosing is the standard regimen for all populations 2, 3
- On-demand (2-1-1) dosing of TDF/FTC is an alternative option ONLY for cisgender men who have sex with men (MSM) having planned receptive anal sex 1, 2
- Daily dosing is especially critical for women, as tenofovir concentrates at 10-fold lower levels in vaginal tissue than in rectal tissue 5, 6
Injectable PrEP Option
- Injectable cabotegravir administered every 8 weeks is recommended (pending regulatory approval and availability) as PrEP for cisgender men and transgender women who have sex with men 1, 3
Considerations for Specific Populations
For MSM and Transgender Women
- TDF/FTC daily is effective and well-established 1, 2
- TAF/FTC is an alternative with better bone and renal safety profiles 1, 2, 4
- 2-1-1 dosing of TDF/FTC can be considered for planned sexual encounters 1
For Cisgender Women
- Only daily TDF/FTC is recommended due to pharmacokinetic differences in drug concentration in vaginal tissues 5, 6
- TAF/FTC is not currently recommended for cisgender women due to insufficient data 2
- On-demand dosing is NOT recommended for women 2, 5
For People with Renal Concerns
- TAF/FTC is preferred for individuals with or at risk for kidney dysfunction (creatinine clearance <60 mL/min) 1, 7, 4
- Regular monitoring of renal function is essential for all PrEP users, especially those on TDF/FTC 1
For People with Bone Health Concerns
- TAF/FTC is preferred for individuals with or at risk for osteopenia or osteoporosis 1, 7, 4
- TDF has been associated with decreased bone mineral density 4
Monitoring Requirements
Pre-Initiation Testing
- Combined HIV antibody and antigen testing (with HIV RNA testing if acute infection is suspected) 1, 2
- Serum creatinine level and estimated creatinine clearance 1, 2
- Hepatitis B surface antigen 1, 2
- Hepatitis C IgG antibody 1, 2
- Genital and non-genital STI testing 1, 2
- Pregnancy testing for individuals of childbearing potential 1
Follow-Up Monitoring
- HIV testing at 1 month and quarterly thereafter 1, 2
- Creatinine assessment at least every 6 months 1
- STI testing quarterly 1, 2
- PrEP prescriptions should not exceed 90 days without interval HIV testing 1, 3
Important Clinical Considerations
- Rule out acute HIV infection before initiating PrEP to avoid development of resistance 1, 8
- For patients with suspected HIV infection while on PrEP, additional antiretroviral agents should be added pending resistance testing results 1, 8
- Lamivudine (3TC)/TDF may be an appropriate alternative to FTC/TDF in resource-limited settings due to comparable pharmacologic profiles and lower cost 9
- PrEP does not protect against other sexually transmitted infections, so regular STI screening is essential 1, 2
Potential Pitfalls
- Initiating PrEP during undiagnosed acute HIV infection can lead to resistance development 8
- Inadequate adherence significantly reduces PrEP effectiveness 1, 2
- Discontinuing PrEP in patients with chronic hepatitis B can cause hepatitis flares 2
- Underestimating the importance of daily dosing for women can lead to inadequate protection 5, 6