Synopsis
Make an exposure-specific PEP decision under time pressure, begin a complete course safely, and connect follow-up testing with longer-term sexual-health prevention.
- Treat PEP assessment as urgent: an indicated course should start as soon as possible, preferably within 24 hours and no later than 72 hours from exposure.
- Base the decision on fluid, anatomical route, mucosal or percutaneous injury, source HIV information and documented viral suppression; demographic labels cannot substitute for this history.
- Draw baseline laboratory HIV, kidney, liver, hepatitis B and C, pregnancy and exposure-site STI samples promptly, while ensuring that testing does not delay the first dose.
Key red flags
A person close to the 72-hour boundary needs a prescribing decision now, with referral arranged after the first dose if PEP is indicated.
Fever, rash, sore throat or lymph-node enlargement that started before this presentation may represent HIV acquired earlier and calls for urgent antigen–antibody and RNA testing.
A reactive or unresolved baseline HIV result changes the task from prevention to diagnostic assessment; a two-drug PrEP regimen must not be used to cover uncertainty.
Renal disease or chronic hepatitis B affects tenofovir and emtricitabine management, but a clearly eligible exposure still needs immediate specialist-supported action.
Pregnancy and breastfeeding require an informed urgent regimen review and are not reasons to refuse otherwise indicated prophylaxis.
After sexual assault, address injuries, emergency contraception, hepatitis B prevention, other STI care, safeguarding and forensic choices in the same trauma-informed pathway.
Condomless receptive anal or vaginal contact can warrant PEP when source virus may be transmissible; timing and reliable suppression determine the decision.
A blood-filled hollow-bore needle injury or shared injecting equipment offers direct access through the skin and needs immediate assessment.
Blood reaching an eye, mouth or damaged skin differs clinically from blood resting on intact skin, which does not transmit HIV.
A compatible systemic illness already underway may signal earlier acquisition, so RNA testing and specialist review accompany any prevention decision.
Investigation priorities
Identify established infection and create the serological starting point for post-course testing.
Management branches
An adult attends 18 hours after receptive anal sex with a source known to have untreated HIV.
- Confirm timing, route, fluid, source treatment information, consent circumstances and medicines while checking for injury or other urgent needs.
- Collect HIV, renal, liver, hepatitis, pregnancy and site-directed STI samples as applicable without waiting for their results.