What is the recommended regimen for Truvada (emtricitabine and tenofovir disoproxil fumarate) for Pre-Exposure Prophylaxis (PrEP)?

Truvada for PrEP: Recommended Regimen

The standard regimen for Truvada (emtricitabine 200 mg/tenofovir disoproxil fumarate 300 mg) for HIV pre-exposure prophylaxis is one tablet taken orally once daily, which is the recommended first-line option for all populations at risk of HIV acquisition. 1, 2

Daily Dosing Protocol

Standard Initiation and Maintenance

• Take one tablet of Truvada (FTC 200 mg/TDF 300 mg) orally once daily for continuous protection against HIV acquisition 1
• For men who have sex with men (MSM), start with a double dose (2 tablets) on the first day, followed by once-daily dosing to achieve maximal protection within 24 hours 1, 2
• For all other populations (heterosexual individuals, transgender persons, people who inject drugs), maximal protection is achieved approximately 7 days after initiation 1, 2

Duration After Last Exposure

• For MSM with rectal exposure: Continue Truvada for 2 days (2 doses) after the last at-risk sexual exposure 1, 2
• For vaginal, neovaginal, or "front-hole" exposures: Continue Truvada for 7 days after the last at-risk exposure, as tenofovir concentrates at 10-fold lower levels in vaginal tissue compared to rectal tissue 3, 2, 4

Alternative Dosing: Event-Driven (2-1-1) Regimen

Event-driven PrEP is recommended ONLY for cisgender men who have sex with men and should not be used in other populations. 1, 3

• Take 2 tablets together 2-24 hours before anticipated sexual activity 1
• Take 1 tablet 24 hours after the first dose 1
• Take 1 tablet 24 hours after the second dose (48 hours after last sexual contact) 1
• Continue daily single doses if sexual activity continues until 48 hours after the last sexual contact 1

Critical caveat: This regimen is contraindicated for transgender men, women, and people who inject drugs because efficacy data exist only for MSM with receptive anal intercourse 3

Pre-Initiation Testing Requirements

Before starting Truvada for PrEP, perform the following tests 2, 4:

• Combined HIV antibody and antigen testing (to rule out existing HIV infection)
• Serum creatinine level and estimated creatinine clearance (baseline renal function)
• Hepatitis B surface antigen (HBsAg)
• Hepatitis C IgG antibody
• Genital and nongenital testing for Neisseria gonorrhoeae and Chlamydia trachomatis by nucleic acid amplification test (NAAT)
• Pregnancy testing for individuals of childbearing potential

Ongoing Monitoring Schedule

Quarterly Monitoring (Every 3 Months)

• Combined HIV antibody and antigen testing 2, 4
• STI screening (gonorrhea, chlamydia, syphilis) at genital and nongenital sites 1, 2
• Pregnancy testing for individuals of childbearing potential 4

Annual Monitoring

• Creatinine clearance measurement (after initial check at first quarterly visit) 1, 2

Important prescribing limitation: PrEP prescriptions should not exceed 90 days without interval HIV testing to avoid inadvertent treatment of undiagnosed HIV infection with suboptimal therapy 2, 4

Special Population Considerations

Pregnancy and Breastfeeding

• Daily Truvada is safe and recommended during pregnancy and breastfeeding 1, 2
• Continue daily dosing without interruption throughout pregnancy 1

Renal or Bone Health Concerns

• For MSM with creatinine clearance between 30-60 mL/min, or those with osteopenia, osteoporosis, or high risk for these complications, consider switching to tenofovir alafenamide/emtricitabine (TAF/FTC) instead of TDF/FTC 1, 2

Transgender Individuals

• Transgender men require the full 7-day protective window after initiation or interruption if they have vaginal tissue, not the 2-day window applicable to rectal tissue 3
• Event-driven dosing is inappropriate for transgender individuals 3

Common Pitfalls to Avoid

• Never reduce dosing frequency to every other day, as daily dosing is required for optimal protection, particularly for individuals with vaginal tissue exposure 3
• Do not use event-driven dosing in women or transgender individuals, as efficacy is only established for cisgender MSM 1, 3
• Do not prescribe beyond 90 days without HIV testing, as this risks treating undiagnosed HIV with dual therapy instead of triple therapy 2
• Monitor adherence closely, as protection is highly dependent on consistent daily use—studies show 44-75% efficacy with variable adherence 5, 6

Safety Profile

• Most common adverse effects are mild to moderate gastrointestinal symptoms (nausea, vomiting, diarrhea) 7
• Long-term monitoring should include renal function and bone mineral density 5, 7
• No unexpected serious adverse events have been reported in major clinical trials 5, 6
• Truvada maintains prophylactic efficacy even against some drug-resistant HIV strains 8