Post-exposure prophylaxis (PEP) for HIV must be initiated as soon as possible, ideally within 2 hours, and preferably within 24 hours of exposure. However, the period during which PEP is most efficacious is often said to be within 72 hours of exposure.
Most exposures have only a low risk of HIV transmission even in the absence of PEP.
PEP given to HIV-negative people reduces likelihood of HIV seroconversion by approximately 80%.
Duration of treatment is 28 days.
New antiretroviral treatment regimens for PEP offer low risk of toxicity.
There is an absence of randomized controlled studies evaluating PEP.
Post-exposure prophylaxis (PEP) is the administration of antiretroviral therapy (ART) to HIV-negative people who may have been occupationally or sexually exposed to HIV. Once exposed to HIV, there may be a brief period before the infection is established, during which ART may successfully prevent viral replication. PEP should be given as soon as possible following exposure; a 28-day course of treatment is recommended.
History and exam
Key diagnostic factors
- exposure to HIV within past 72 hours
- breakage, slippage, or nonusage of a condom
- history of ejaculation from source
- trauma or skin break
- genital ulcers
- source from high-risk group for HIV viremia
- source from geographic area with high HIV prevalence
- high-risk sexual history in exposed person
- detectable HIV viral load in source
Other diagnostic factors
- history of negative HIV test in source
- source with hepatitis coinfection
- antiviral HIV resistance in source
- current prescription or nonprescription medications
- history of drug allergies
- flu-like illness
- blood transfusion from HIV-positive donor
- sharing injecting equipment
- needlestick injury
- receptive anal intercourse
- receptive vaginal intercourse
- mucus membrane exposure
- insertive anal intercourse
- insertive vaginal intercourse
- receptive oral sex (fellatio)
1st investigations to order
- HIV antigen/antibody blood test (blood ELISA or EIA)
- rapid HIV point of care test (POCT)
- renal function tests
- liver function tests (LFTs)
- hepatitis B serology
- hepatitis C antibody
- syphilis serology
- pregnancy test
- screening for other STIs
Investigations to consider
- HIV viral load if symptoms of HIV seroconversion
adults or adolescents ≥13 years: nonpregnant
pregnant or breastfeeding
- UK guideline for the use of HIV post-exposure prophylaxis
- PEP to prevent HIV infection
Hepatitis C: what is it?
HIV: prevention treatment (PrEP) for people at high riskMore Patient leaflets
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