They call it the HIV "morning after pill," for those situations when you've been exposed to HIV through a known positive partner, by blood or other at-risk exposure. If you have been exposed to HIV in the last 72 hours, you may be able to take an HIV medication regimen called Post Exposure Prophylaxis (or PEP) to help reduce your risk of infection.

I think I was exposed to HIV. What should I do?

The Center for Disease Control recommends that those exposed to HIV start PEP within 48 to 72 hours after exposure to blood, genital secretions, or other potentially infected body fluids of a persons known to be HIV infected.

Some health agencies and clinics recommend taking PEP in as little as 36 hours after exposure.

If you've been exposed to HIV, go to a health clinic as soon as possible. Remember, you only have a few hours. Be candid about how you were exposed. You may feel more comfortable speaking with a LGBT health care professional, but don't wait to find one.

Not all HIV testing sites administer PEP, so be sure to ask beforehand.

What is Post Exposure Prophylaxis (PEP)?

PEP is a prophylaxis (preventative) medication (or series of medications) administered after suspected HIV exposure. Post Exposure Prophylaxis does not prevent HIV; it helps decrease the likelihood of HIV infection from the exposure.

Post Exposure Prophylaxis regimens (which can be in the form of a two or three pill combination) was originally developed for health care professionals who were exposed to HIV through needle sticks and patient fluids. PEP is now available for non-occupational applications (or for people that are exposed to HIV outside of work).

What are the PEP drugs and how long do I have to take them?

A two or three pill combination (depending on the severity of exposure) is prescribed for 28 days. About.com HIV/AIDS Guide Mark Cichocki, R.N. describes the two and three pill combinations in his article Decrease the Risk with Post-Exposure Prophylaxis.

How much does PEP cost?

PEP costs can be substantial, but this should not deter you from seeking treatment after exposure. Many states offer health grants to clinics if the regimen has been started within a certain time frame. For instance, you can qualify for free or low cost PEP at Callen-Lorde Community Health Center in New York City if you seek treatment within 36 hours of exposure. Call your local clinic as soon as possible and ask how you can get PEP at low or no cost. If they do not offer PEP or cannot provide financial assistance, ask for a referral to a clinic that does. Remember, time is against you once you've been exposed; don't wait or spend an excess of valuable time "shopping" for the right clinic.

What are the side effects of PEP?

PEP medications may include a combination of Retrovir (zidovudine, AZT), Epivir (lamivudine), Combivir (Retrovir + Epivir), Emtriva (emtricitabine, FTC) or Kaletra (lopinavir + ritonavir). Mark Cichocki provides drug descriptions and a list of common side effects for medication.

What about HIV testing?

Your doctor or health clinic will test you for HIV before they prescribe the PEP. They will also test you 4 to 6 weeks, 3 months, and possibly 6 months after exposure just to be sure.

How does exposure to HIV happen?

HIV exposure can happen through blood, genital secretions, or other potentially infected body fluids. Accidents happen (at work and in the bedroom). A condom may break for a serodiscordant couple. A poor decision may have been made to bareback after a night out partying. There are a number of scenarios where you may find yourself exposed to HIV.

Shouldn't they give PEP to everyone just in case?

It's important to understand that PEP is not for continued at-risk behavior, such as repeated unprotected sex. PEP shouldn't be seen as as HIV control or prevention, just as the morning after pill for pregnancy shouldn't be seen as birth control. PEP does not prevent HIV; it only decreases the likelihood of infection after exposure. The best way to prevent HIV is to prevent exposure. PEP is administered on a case-by-case basis and only if exposure was in the determined window, in some cases 36 hours.

The Center for Disease Control warns that "PEP is not 100% effective in preventing transmission and because antiretroviral medications carry a certain risk for adverse effects and serious toxicities, PEP should be used only for infrequent exposures. Persons who engage in behaviors that result in frequent, recurrent exposures that would require sequential or near-continuous courses of antiretroviral medications (e.g., discordant sex partners who rarely use condoms or injection-drug users who often share injection equipment) should not take PEP. In these instances, exposed persons should instead be provided with intensive risk-reduction interventions."

Where can I get more information on PEP?

• In his article Decrease the Risk with Post-Exposure Prophylaxis About.com HIV/AIDS Guide Mark Cichocki describes PEP, including the side effects and the drug combinations.
• Also, read the Center of Disease Control recommendations on Antiretroviral Postexposure Prophylaxis