Executive summary
PrEP (pre-exposure prophylaxis) prevents HIV acquisition for people at ongoing risk. In the UK it is usually accessed via sexual health services. Primary care can add value by identifying candidates, explaining options, and arranging referral with clean baseline information.
Eligibility (high-yield prompts)
- Condomless sex with partners of unknown HIV status or higher-risk networks.
- Recent bacterial STI, repeated PEP use, chemsex, or high partner turnover.
- People with an HIV-positive partner not consistently virally suppressed (specialist advice).
- Injecting drug use with sharing risk.
Always confirm HIV negative before starting PrEP; do not start if acute HIV is suspected (fever/rash/sore throat after a recent exposure) — urgent specialist assessment instead.
Dosing options (check local protocol)
- Daily PrEP: TDF/FTC 245/200 mg once daily (common default).
- Event-based PrEP (2-1-1): used in some populations (e.g., MSM) per guideline: 2 tablets 2–24 hours before sex, then 1 tablet 24 hours later, and 1 tablet 48 hours after the first dose. If sex continues on subsequent days, continue 1 tablet daily until 2 days after last sex.
Important: event-based dosing is not appropriate for all exposure types (for example vaginal exposure often requires daily dosing for adequate tissue levels). Follow BHIVA/local sexual health guidance.
Baseline tests + monitoring (what matters clinically)
- Baseline: HIV test, renal function/eGFR, hepatitis B status (HBsAg/anti-HBc/anti-HBs), STI screen, pregnancy test where relevant.
- Renal: TDF/FTC is usually used with eGFR ≥60 (thresholds vary); use specialist advice for lower eGFR or renal risk.
- Follow-up: typically every 3 months for HIV testing, STI screening as indicated, adherence/side-effects, and renal monitoring (frequency depends on age/risk).
HBV note: TDF/FTC is active against hepatitis B; stopping PrEP in someone with chronic HBV can precipitate a flare. Ensure HBV status is known and managed with specialist input.