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Educational draft · awaiting clinical reviewUse Rapid for revision, not patient-care decisions. Check current national and local guidance and the BNF or BNFC before acting.

HIV post-exposure and pre-exposure prophylaxis

Infectious diseases, microbiology and sexual health · UK scope · Sources checked 27 Aug 2026 · Clinical review pending

RapidFull
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Time-critical HIV exposure

A substantial sexual, needlestick or blood exposure within 72 hours requires immediate risk assessment because PEP effectiveness falls with every delay.

Action: Start PEP as soon as possible, ideally within 24 hours and no later than 72 hours, after rapid baseline specimens; do not wait for source results, specialist appointments or full renal and hepatitis results when the exposure is clearly eligible.

Synopsis

Assess HIV exposure urgently, start and complete indicated 28-day PEP within the effective window, and deliver PrEP with reliable HIV, renal, hepatitis B and STI monitoring.

  • PEP is an emergency: start ideally within 24 hours and no later than 72 hours after a substantial exposure.
  • Assess fluid, route, mucosal or percutaneous injury, source viral load and treatment, prevalence and modifying factors without using stigmatizing identity assumptions.
  • Take baseline fourth-generation HIV, renal, liver, hepatitis B and C, pregnancy and STI tests, but do not delay the first PEP dose.
  • A standard UK PEP course is tenofovir disoproxil 245 mg plus emtricitabine 200 mg once daily with raltegravir 1200 mg once daily for 28 days.
  • Provide the complete 28-day supply or a reliable rapid completion route, interaction advice and an early adherence check.
  • PrEP is started only after HIV-negative status and acute infection have been adequately excluded.
  • The 2025 UK guidance offers event-based dosing to all PrEP users: use a two-day post-risk tail for anal or insertive sex and seven days for receptive vaginal, neovaginal or injecting exposure.
  • PrEP care includes repeat HIV and STI testing, renal monitoring, hepatitis B continuity, adherence and vaccination review.

Key red flags

Exposure approaching 72 hours needs immediate prescribing rather than referral delay.

Fever, rash, pharyngitis or lymphadenopathy before PEP or PrEP raises acute HIV and requires HIV RNA assessment.

A reactive or indeterminate baseline HIV test means PrEP must not be used as an incomplete treatment regimen.

Known hepatitis B complicates stopping tenofovir and emtricitabine and requires liver and HBV planning.

Pregnancy or breastfeeding never justifies automatic denial of indicated PEP, but needs urgent specialist prescribing review.

Sexual assault requires trauma-informed care, emergency contraception, hepatitis B prevention, STI prophylaxis decisions, safeguarding and forensic options alongside HIV care.

Sexual mucosal exposure

Condomless receptive anal or vaginal exposure to a source with transmissible HIV may warrant PEP according to viral load and context.

Occupational sharps injury

A hollow-bore injury contaminated with blood carries greater risk than intact-skin contact and triggers immediate occupational assessment.

Needle-sharing exposure

Shared injection equipment containing fresh blood can transmit HIV and requires PEP, hepatitis and harm-reduction review.

Possible acute HIV

Fever, rash, sore throat, nodes or diarrhoea after recent risk requires RNA testing before a PrEP-only regimen.

Investigation priorities

01
Baseline fourth-generation HIV testFirst step

Exclude established infection before PEP or PrEP and provide a comparison for follow-up.

Management branches

NOWStart eligible PEP immediately

A substantial exposure occurred within the preceding 72 hours.

  1. Establish exact time, fluid, route, injury, source HIV status and viral suppression and whether the exposure was consensual.
  2. Take baseline HIV, renal, liver, hepatitis, pregnancy and site-specific STI specimens without delaying the first dose.
  3. Give tenofovir disoproxil and emtricitabine plus raltegravir immediately and provide access to the full 28-day course.
  4. Arrange early specialist or sexual-health review for adherence, results, side effects, safeguarding and ongoing prevention.

Key medicines

Tenofovir disoproxil and emtricitabine for PEPGive one tablet containing tenofovir disoproxil 245 mg and emtricitabine 200 mg orally once daily for 28 days as the PEP backbone.Check renal and hepatitis B status, avoid unreviewed nephrotoxins and do not stop chronic HBV-active therapy without a liver plan.
Raltegravir for PEPGive 1200 mg orally once daily for 28 days with tenofovir disoproxil and emtricitabine under the current UK PEP regimen.Check formulation, separate from polyvalent cation antacids as advised, review pregnancy and interactions, and avoid missed doses.
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Sources and review status4 sources · checked 27 Aug 2026 · clinical review pending+
Sources

Sources and review status

National guidance is shown before implementation-dependent detail. Typical adult dose examples remain subject to patient factors, contraindications and the live BNF or specialist protocol. Source check completed 27 Aug 2026; clinical approval remains outstanding.

  • BHIVA and BASHH UK Guideline for the use of HIV Post-Exposure Prophylaxis
  • BHIVA and BASHH PrEP guidelines
  • NHS Pre-exposure prophylaxis information
  • University of Liverpool HIV Drug Interactions

Editorial contact: Doctor’s Passport editorial team. Source-check date is separate from clinical approval. Report a content problem · Content changes

Authoring stateRapid draftClinical stateAwaiting reviewJurisdictionUnited Kingdom