PEP – Post Exposure Prophylaxis

What is PEP?
PEP stands for post-exposure prophylaxis. It means taking antiretroviral medicines (ART) after being potentially exposed to HIV to prevent becoming infected.

PEP must be started within 72 hours after a possible exposure to HIV, but every hour counts so the sooner you start PEP, the better. If you’re prescribed PEP, you’ll need to take it once or twice daily for 28 days. Although not 100% successful, PEP is effective in preventing HIV when administered correctly.

Learn more about how to protect yourself and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool.

Is PEP right for you?
If you’re HIV-negative or don’t know your HIV status, and in the last 72 hours you:

  1. think you may have been exposed to HIV during sex (for example, if the condom broke),
  2. shared needles and preparational tools (for example, cotton, cookers, water), to prepare drugs, or
  3. were sexually assaulted,

If any of the above apply to you, then talk to your health care provider or an emergency room doctor about PEP right away.

PEP should be used only in emergency situations and must be started within 72 hours after a recent possible exposure to HIV. PEP is not a substitute for the regular use of other proven HIV prevention methods, such as pre-exposure prophylaxis* (PrEP); using condoms the correct way every time you have sexual intercourse with your partner; and only using sterile needles and works every time you inject.

*this link will send users to our PrEP page.

Although PEP is very effective,it is not 100% guaranteed. You should continue to use condoms with sexual partners, and practice safe injection practices while taking PEP. These strategies can protect you from being exposed to HIV, and reduce the chances of transmitting HIV to others if you do become infected while you’re on PEP.

Learn more about how to protect yourself and get information tailored to meet your needs from CDC’s HIV Risk Reduction Tool.

Does PEP have any side effects?
PEP is safe but may cause side effects like nausea in some people. These side effects can be treated and aren’t life-threatening.

Where can you get PEP?
If you’re prescribed PEP after a sexual assault, you may qualify for partial or total reimbursement for medicines and clinical care costs through the Office for Victims of Crime, funded by the US Department of Justice (see the contact information for each state).

If you’re prescribed PEP for another reason and you cannot get insurance coverage (Medicaid, Medicare, private, or employer-based), your health care provider can apply for free PEP medicines through the medication assistance programs run by the manufacturers. Online applications can be faxed to the company, or some companies have special phone lines. These can be handled urgently in many cases to avoid a delay in getting medicine.

If you’re a health care worker who was exposed to HIV on the job, your workplace health insurance or workers’ compensation will usually pay for PEP.

Can you take a round of PEP every time you have unprotected sex?
PEP should be used only in emergency situations.

PEP is not the right choice for people who may be exposed to HIV frequently—for example, if you often have sex without a condom with a partner who is HIV-positive. Because PEP is given after a potential exposure to HIV, more drugs and higher doses are needed to block infection than with PrEP, or pre-exposure prophylaxis. PrEP is when people at high risk for HIV take HIV medicines (sold under the brand name Truvada) daily to lower their chances of getting HIV. If you are at ongoing risk for HIV, speak to your doctor about PrEP. Also, read our article on PrEP.

Additional Resources
PEP basics.
Proven HIV prevention methods.