Answer
HIV PEP should be initiated as soon as possible, preferably within hours of exposure. Considerations include the following:
-
Although animal studies demonstrate that PEP is likely to be less effective when started more than 72 hours after exposure, the interval after which no benefit is gained from PEP in humans is undefined.
-
If PEP initiation is delayed, the likelihood increases that benefits might not outweigh the risks inherent in taking antiretroviral medications.
-
Initiating therapy after a longer interval (eg, 1 week) might still be considered for exposures that represent an extremely high risk of transmission.
Because 4 weeks of PEP appeared protective in in vitro, animal, and occupational studies, PEP should be administered for 4 weeks, if tolerated.
