What Is Post-Exposure Prophylaxis?
Post-exposure prophylaxis (PEP) is a medicine you take after you’ve come into contact with HIV, the virus that causes AIDS, to lower your chance of infection.
You must start PEP within 72 hours (3 days) after you were exposed to HIV. The sooner you start it, the better. If you start it 3 days or more after exposure, it has little to no effect.
Who Might Need Post-Exposure Prophylaxis?
PEP may help:
- People who think they might have been exposed to HIV during sex
- People who have been sexually assaulted
- Drug users who recently shared needles or other related items
- Health care workers who think they've been exposed to HIV on the job
If you think you were exposed to HIV, go to the hospital or see your doctor as soon as possible. They can help you figure out whether you need PEP.
Where to Get PEP
If you think you've been exposed to HIV, get medical help right away from:
- An emergency room or urgent care center
- A sexual health clinic
- Your family doctor (they may send you to another doctor or the ER if they're not experienced with PEP)
If you’re seeking care after a sexual assault, see a sexual assault nurse examiner who can collect evidence, offer counseling, and provide follow-up care. Most emergency rooms offer these services.
How Does PEP Work?
The same drugs that treat HIV can fight the virus as it tries to infect you. These medications are called antiretrovirals. They work by stopping HIV from copying itself and settling in your body.
Post-exposure prophylaxis drugs
PEP is a combination of three drugs. You take them once or twice a day for 28 days:
- For adults, the CDC recommends tenofovir, emtricitabine (these two drugs come in one pill), and a third drug, either raltegravir or dolutegravir.
- People who are in early pregnancy, who are sexually active and could become pregnant while taking PEP, or who were sexually assaulted without birth control should take raltegravir rather than dolutegravir because of the risk of birth defects.
- Children aged 2 or older who need PEP usually get the same drugs in different doses.
Your doctor will take a sample of your blood when you start PEP and may want to test for other sexually transmitted diseases. You’ll need HIV tests after you’re through with PEP to make sure you didn’t get the virus.
If you're on PEP, use condoms when you have sex to lower the chances of getting HIV again or spreading it if you are already infected.
If PEP doesn’t work and you get HIV, it might be because the virus resists some of the medications.
Post-Exposure Prophylaxis Side Effects
Side effects of PEP include:
Rarely, the drugs can cause serious health issues, including liver problems.
Can I Take PEP Every Time I Have Unprotected Sex?
PEP is only for emergencies. Don’t use it in place of safe sex or new sterile needles.
If you're exposed to HIV a lot — for example, if you have multiple sex partners or use injected drugs — talk with your doctor about pre-exposure prophylaxis (PrEP). That’s a medicine you take every day to keep HIV from taking hold in your body.
How Effective Is PEP?
It’s hard to measure exactly how well PEP works, but it could lower your risk of getting HIV by over 80%. How well it works depends a lot on whether you take PEP every day for 28 days and avoid any more HIV exposure. If you use PEP correctly and consistently, its effectiveness could be higher than 80%.
Post-Exposure Prophylaxis Cost
Without health insurance, a full course of PEP treatment can cost you between $600 and $1,000, plus other emergency medical costs at a hospital ER. There are ways to lower the cost of post-exposure prophylaxis, including:
Office for Victims of Crime. If your doctor prescribes PEP after you were sexually assaulted, the federal Office for Victims of Crime might cover part or all of your related healthcare costs.
Health insurance or workers' compensation. If you work in health care and have had contact with HIV on the job, your health insurance or workers’ compensation will probably pay for PEP.
Patient assistance programs (PAPs). These programs, sponsored by drug companies, can help you get the medications you need for free or at a low cost.
Copayment assistance programs (CAPs). Drug companies also offer these programs to lower or cover your deductibles, coinsurance, and copayment costs. Your doctor may help you with the forms.
Takeaways
Post-exposure prophylaxis (PEP) is a medicine that helps lower your chances of getting HIV. You take it to stop the virus after you might have been exposed through sex or drug use. It's important to start PEP within 72 hours of possible exposure to HIV for it to work; the sooner you start, the better. For the medicine to be effective, you'll need to take it every day for 28 days.
Continue using condoms while on PEP to avoid coming into contact with HIV again or, if you have the virus, sharing it with others. After a full course of PEP, be sure to take an HIV test to know your status. If you need help paying for PEP, talk to your doctor about patient or copayment assistance programs or other ways to cover the costs.
Post-Exposure Prophylaxis FAQs
Can you take PEP when you are pregnant or breastfeeding/chestfeeding?
Yes. There are no issues with using PEP during pregnancy and breastfeeding. If you are pregnant or breastfeeding, talk to your doctor about PEP and find out which PEP plan is best for you.
Can I have sex when taking PEP?
If possible, wait until you finish taking PEP and get a negative HIV test result before having sex again. If you can't wait, always use condoms correctly to protect others from risk.
When is PEP not recommended?
You don’t need PEP if you already have HIV. Don’t use PEP if more than 72 hours have passed since your exposure, as it probably won’t work. Also, you should not use PEP if you were exposed to nonblood secretions such as urine, saliva, sweat, tears, or nasal fluids, as your risk of getting HIV from these sources is very low.
