HIV Post-Exposure Prophylaxis (PEP)

What is HIV PEP?

“Prophylaxis” is the prevention of disease. “HIV PostExposure Prophylaxis” (PEP) is taking specific medication after potential exposure to HIV for 28 days to help prevent HIV infection.  HIV PEP is different from HIV PreExposure Prophylaxis (PrEP), which is medication taken regularly before exposure to HIV to prevent infection

How effective is it?

PEP was originally designed for use with medical providers who were exposed to HIV in healthcare settings through needle sticks and has been associated with a decreased risk of infection if administered immediately after exposure.

The US Centers for Disease Control and Prevention (CDC) later devised guidelines for the administration of PEP in non-occupational settings, such as exposure via sexual contact or injection drug use. While definitive evidence is not available to support the effectiveness of PEP administered after exposure to HIV through sex or injection drug use, data does support the view that PEP may reduce the risk for acquiring HIV.

How do you decide if you should take it?

Two important factors to consider are: 1) the likelihood of infection from a specific act and 2) the HIV status of the source (a sexual partner or someone you shared needles with). Activities at highest risk for transmission of HIV are unprotected anal sex as the bottom, sharing needles or blood transfusions. Activities such as unprotected anal sex as a top, vaginal sex and oral sex represent more moderate risk.


Another important factor is the HIV status of the source. If this person is known to be HIV+ and you engaged in a behavior at high risk for transmission of HIV, PEP may be warranted. Even if you do not know the HIV status of the source, PEP still may be prescribed by a provider. This is up to an individual provider.


If you are interested in HIV PEP, talk to your health care provider. Because PEP must be taken within 72 hours after exposure you may need to visit an urgent care or emergency room facility to be seen more promptly, although standards of care and familiarity with PEP vary widely across emergency rooms in the Portland-Metro area. Some facilities offer starter packs of medication which allow you to begin taking PEP immediately. If you visit a healthcare facility and inquire about PEP but encounter difficulties, you can suggest the provider call the National Physician’s PEP Hotline which offers advice for providers on administering PEP (1-888-448-4911). If you are uninsured or worried you may not be able to afford the medication insurance co-pays, you may be able to receive some PEP medication for free. Have your healthcare provider call the Gilead Advancing Access hotline at 1-800-226-2056.


If you are in relationship with someone who is HIV+ and have a high-risk exposure, you may find it easier to contact his/her HIV provider for access to PEP. Pivot/Cascade AIDS Project and the Multnomah County STD HIV Hepatitis C Program do not offer access to PEP.


Other factors to consider:

  • The medication is strong, has potential for side effects, and requires ongoing monitoring by a health care provider.
  • You must complete the full 28-day cycle of medication for it to be effective against acquisition of HIV.
  • The medication is expensive and HIV PEP may not be covered by your health insurance carrier.
  • PEP is not recommended for those who have had or plan to have repeated high-risk HIV exposures.
  • PEP does not protect against any other sexually transmitted infections (STIs).

Whether you consider HIV PEP or not, it is important to understand other ways to protect yourself including:

  • Using condoms correctly and consistently.
  • Getting tested to know your status and your partner(s) status for certain, and getting tested every three months if you have multiple partners with whom you share any risk for HIV.
  • Getting tested regularly  – and treated if needed – for other STIs, such as syphilis and gonorrhea, which increase your risk of acquiring HIV through unprotected anal, vaginal or oral sex.
  • Getting information and support to reduce drug use and sexual risk behavior.
  • Reducing your number of sexual partners.