What Is PEP for HIV?

Post-exposure prophylaxis (PEP) is a short course of HIV drugs that is commonly taken immediately after engaging in a high-risk event or involuntary exposure. PEP stops HIV seroconversion—the period during which the body starts producing detectable levels of HIV antibodies—by killing the infected cells. Simply put, these drugs can prevent HIV from taking hold of your immune system and wreaking havoc if taken right away. In order for PEP to be effective, it must be started within 72 hours of possible exposure.

man sitting on bed with PEP

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What Is PEP?

PEP is a way to help prevent the transmission of HIV in an HIV-negative person who may have been recently exposed to the virus. PEP consists of taking 3 HIV antiviral drugs for 28 days after exposure to the virus. These drugs include:

  • Tenofovir
  • Emtricitabine
  • Raltegravir or dolutegravir

Ideally, the medication should be started immediately, within one to two hours of exposure.

A PEP supply of three to five days is usually first given for emergency use, followed by the rest of the 28-day dose. PEP should not be confused with PrEP which involves taking two HIV medications on an ongoing basis, before, during, and after possible exposure to HIV.

Who Should Use It?

PEP should be used by those who come into single contact with the HIV virus. The most common high-risk situations are within the occupational context, such as an inadvertent needlestick at the hospital, or the non-occupational context, such as sexual exposure or injection drug use.

PEP is only intended for emergencies and should not be used if you are regularly exposed to HIV.

Other groups that may need PEP are:

  • Those who have been sexually assaulted
  • Those who are unclear if a sexual partner has or had been exposed to HIV
  • Anyone who engages in needle-sharing 

Of note, if you are pregnant and have been exposed to HIV, your doctor will prescribe PEP with raltegravir instead of dolutegravir to limit the risk of birth defects.

When to Call Your Doctor

PEP is highly effective. If side effects last for more than two weeks, contact a health care professional.

If you feel the following symptoms you may be experiencing side effects from PEP:

  • Fatigue
  • Diarrhea
  • Nausea
  • Abdominal cramps
  • Bloating
  • Headache
  • Vivid dreams
  • Insomnia
  • Depression
  • Increased thirst
  • Vomiting

Talk to your doctor or a health care provider if you develop symptoms of fever or rash during or after PEP use, as this may be a sign that the medication has not worked and you are experiencing the first signs of acute HIV infection.

PEP is not 100% effective so there are times when the drug will not prevent the disease.

The following symptoms may signal the acute phase of HIV infection:

  • Fever
  • Chills
  • Rash
  • Night sweats
  • Muscle aches
  • Sore throat
  • Fatigue
  • Swollen lymph nodes
  • Mouth ulcers

If you experience any of these symptoms while on PEP, contact a health care professional immediately. 

How Do You Take PEP?

PEP consists of two pills that you take one to two times per day for 28 days. Ideally, the first dose of PEP should be administered immediately, within two hours, but no later than 72 hours after an exposure because the effectiveness of PEP decreases overtime.

It is important to take all the doses, at the right time and in the right way, to give PEP the best chance of working.

Although PEP does not prevent 100% of HIV infections, it has been shown to decrease the transmission of HIV by more than 80%.

Paying for PEP

PEP is covered by most, if not all insurance plans. If you were exposed to HIV while on the job, workers compensation may cover your drug medication treatment. No matter your method of exposure, PEP should be covered and administered to you by your doctor or another health care professional. 

If you do not have insurance, there are drug company patient assistance programs that may be able to help.

Follow-up Tests

If you are on PEP, a health care professional will ask you to schedule a follow-up appointment within 72 hours. Your appointment will include:

  • HIV testing
  • Lab monitoring for drug toxicity
  • Counseling

Repeat HIV testing will be obtained at 30 and 90 days post-exposure. Testing should be performed using a fourth-generation HIV test. If a fourth-generation test is unavailable, an older generation test may be used but more repeat testing is needed to limit the possibility of a false-negative result.

Repeat HIV testing should be obtained at 6 weeks, 12 weeks, and 6 months minimum. Sometimes these repeat tests are in addition to testing at 30 and 90 days.

If you test positive or develop symptoms of acute retroviral syndrome, an HIV viral load may be obtained.

A Word From Verywell

Although HIV rates have dropped substantially in the past decade, HIV still remains a problem. In order to help prevent the disease, it's important to use condoms, avoid unsafe sexual practices, and avoid the use of non-sterile equipment—including needles.

PEP should not be used as a regular way of preventing HIV and it does not prevent the transmission of other sexually transmitted infections (STIs). Condoms, when used properly, are the most effective way of preventing HIV and most other sexually transmitted infections (STIs).

Having a candid conversation about condom use and STI testing is not only helpful in helping to prevent STIs but is often integral to a happy and healthy sex life. If you or a loved one suspects that you have come into contact with someone who is HIV positive, seek immediate medical attention.

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Article Sources
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  1. Centers for Disease Control and Prevention. Post-exposure prophylaxis (PEP). Updated October 15, 2020.

  2. HIV Prophylaxis Following Occupational Exposure. New York Department of Health AIDS Institute. 2019. Available at: http://www.hivguidelines.org 

  3. Hoenigl M, Green N, Camacho M, et al. Signs or symptoms of acute hiv infection in a cohort undergoing community-based screening - volume 22, number 3—march 2016 - emerging infectious diseases journal - cdc. doi:10.3201/eid2203.151607

  4. DeHaan E. Post-exposure prophylaxis (PEP) to prevent HIV infection. Baltimore (MD): Johns Hopkins University; 2020 Jun.