PEP

PEP

After exposure (“Morning after Pill for HIV”)

Taking antiretroviral medications within 72 hours after an HIV exposure may reduce the risk of HIV infection by >80%
Source:
Antiretroviral Postexposure Prophylaxis After Sexual, Injection-Drug Use, or Other Nonoccupational Exposure to HIV in the United States.
Recommendations from the U.S. Department of Health and Human Services 2005

Post-exposure prophylaxis (PEP) is a medication you take within 72 hours after you may have been exposed to HIV and which helps to prevent infection. An exposure may mean having unprotected sex with someone who has HIV or someone you are concerned may have HIV. Sex may include oral, vaginal, or anal. The sooner you start PEP the better. You need to take the medication for 28 days after your exposure. If you are exposed, you should immediately go to an emergency room or urgent care center or in Rhode Island, you may also page 1-401-460-AIDS(2437).

Resources:

PL AIDS Project: HIV Exposure
AIDS.gov Post Exposure Prophylaxis