Is emtricitabine (Emtriva)/tenofovir (Viread) a Pre-Exposure Prophylaxis (PrEP) medication?

Yes, Emtricitabine/Tenofovir is a Pre-Exposure Prophylaxis (PrEP) Medication

Emtricitabine/tenofovir is the recommended first-line oral PrEP regimen for preventing HIV infection in all at-risk populations. 1

Approved Formulations for PrEP

Two formulations of emtricitabine/tenofovir are approved for PrEP, each with specific indications:

Tenofovir Disoproxil Fumarate/Emtricitabine (TDF/FTC, Truvada)

• This is the primary recommended oral PrEP regimen for all populations at risk of HIV through sexual exposure or injection drug use 1, 2
• Approved for men who have sex with men (MSM), heterosexual men and women, transgender individuals, and people who inject drugs 1, 2
• Can be used as daily dosing or on-demand (2-1-1) dosing for MSM only 1

Tenofovir Alafenamide/Emtricitabine (TAF/FTC, Descovy)

• Recommended only for the specific subset of MSM with creatinine clearance between 30-60 mL/min who have osteopenia, osteoporosis, or are at high risk for these complications 1, 3
• TAF/FTC is NOT recommended for cisgender women or prevention from receptive vaginal sex 3, 2
• TAF/FTC is NOT recommended for on-demand (2-1-1) dosing 3, 2
• While TAF/FTC shows superior bone and renal safety biomarkers compared to TDF/FTC, its HIV prevention efficacy is non-inferior but not superior 1, 4

Dosing Strategies

Daily Dosing (All Populations)

• For MSM: Start with a double dose (2 tablets) on day 1, then once daily; continue for 2 days after last at-risk exposure 1
• For all other populations (women, people who inject drugs): Once daily; continue for 7 days after last at-risk exposure 1
• Maximum protection achieved within 24 hours for MSM after double dose, but approximately 7 days for others 1

On-Demand (2-1-1) Dosing (MSM Only)

• Only validated and recommended for MSM using TDF/FTC, not TAF/FTC 1, 2
• Take 2 tablets 2-24 hours before sexual activity, 1 tablet 24 hours later, and 1 tablet 24 hours after that 1, 2
• Continue daily doses until 48 hours after last sexual contact 1
• Demonstrated 86% risk reduction in the IPERGAY study 2

Critical Population-Specific Considerations

Women

• Daily TDF/FTC is the only recommended option for women 2, 5
• Daily dosing is especially critical because tenofovir concentrates at 10-fold lower levels in vaginal tissue compared to rectal tissue, with faster clearance 2, 5
• Women must take PrEP 6-7 days per week to maximize efficacy, whereas MSM may achieve protection with at least 4 days per week 6
• On-demand dosing is NOT recommended for women 2

People Who Inject Drugs

• Daily TDF/FTC is the only recommended regimen 2
• On-demand PrEP is not appropriate for this population 2

Pregnant and Breastfeeding Individuals

• Daily TDF/FTC is recommended 1

Baseline Testing Requirements Before Initiation

PrEP must not be started in anyone with undiagnosed HIV infection 1

Required baseline tests include:

• Combined HIV antibody and antigen test (within 7 days of first visit) 1, 5
• If acute HIV infection is suspected clinically, perform HIV RNA testing and withhold PrEP pending results 1
• Serum creatinine and estimated creatinine clearance 3, 5
• Hepatitis B surface antigen 3, 5
• Hepatitis C antibody 3, 5
• STI testing: gonorrhea, chlamydia (genital and nongenital by NAAT), syphilis 3, 5
• Pregnancy test for individuals of childbearing potential 5

Ongoing Monitoring

• HIV testing at 1 month after initiation, then quarterly 1, 3
• Creatinine clearance at first quarterly visit, then annually 3
• STI testing quarterly 3, 2
• Pregnancy testing quarterly for individuals of childbearing potential 5
• PrEP prescriptions should not exceed 90 days without interval HIV testing 2, 5

Common Pitfalls to Avoid

• Do not use TAF/FTC for women or people who inject drugs - it lacks efficacy data in these populations 3, 2
• Do not use on-demand dosing for anyone except MSM, and only with TDF/FTC 1, 2
• Do not prescribe TDF-based PrEP for patients with creatinine clearance below 60 mL/min (consider TAF/FTC for MSM with CrCl 30-60 mL/min if bone/renal concerns) 1, 2
• Do not use on-demand PrEP in individuals with active hepatitis B due to risk of hepatitis flare and hepatic decompensation 2
• Do not assume PrEP prevents other STIs - it only prevents HIV 5

Efficacy and Safety

• When adherence is high, TDF/FTC demonstrates excellent HIV prevention efficacy 4, 6
• Drug resistance with PrEP use is infrequent and most likely occurs when PrEP is initiated during undiagnosed acute HIV infection 7
• Both TDF/FTC and TAF/FTC are well tolerated, with low discontinuation rates due to adverse events (1-2%) 4
• Most adverse events are gastrointestinal and typically do not lead to discontinuation 4, 8