Post-Exposure Prophylaxis (PEP)

What is Post-Exposure Prophylaxis (PEP)? 

Post-exposure prophylaxis, also known as PEP for short, is a medicine that can prevent people from contracting HIV. It can be used in emergency situations by people who don’t already have human immunodeficiency virus (HIV) but may have recently been exposed to HIV. PEP can prevent HIV from spreading through your body after a possible HIV exposure. PEP should be taken within 72 hours of a potential exposure. The sooner you start PEP, the more effective it is at protecting against an HIV infection.  

How does PEP work? 

PEP prevents HIV from replicating in the body and therefore stops a permanent HIV infection from developing. For HIV to cause a permanent infection, it must enter the body, infect certain immune cells, and replicate within those cells until it has spread throughout the entire body. PEP can get into the bloodstream as well as genital and rectal tissues to block HIV from spreading and replicating. For PEP to be the most effective, it must be taken as soon as possible but within 72 hours of exposure and continued for as long as a health care provider prescribes. Consistently taking PEP pills builds up the medicine in your bloodstream to prevent a permanent HIV infection. 

Can PEP be used to prevent other STIs as well? 

Unfortunately, PEP can only be used to help prevent HIV.  

However, if you’ve recently experienced a potential exposure to a sexually transmitted infection (STI), you may consider asking your health care provider to prescribe you DoxyPEP. DoxyPEP, also known as STI PEP, is another form of PEP with the main ingredient being the antibiotic, doxycycline. Doxy PEP prevents STIs that spread through bacteria, such as syphilis, chlamydia, and gonorrhea, within 72 hours of sex without a condom. 

Who can benefit from PEP? 

You may benefit from PEP if you think you’ve been recently exposed to HIV through: 

• Sex (for instance, if the condom broke) 
• Sharing needles, syringes, and injecting drugs 
• Sexual assault 
• A possible workplace exposure (for example, a needlestick injury) 

PEP is available through prescription only, so consider immediately reaching out to a health care provider, urgent care provider, or emergency room practitioner if you believe you may have been exposed to HIV.  

Can you take PEP daily to prevent HIV? 

PEP is for emergency situations only. If you’re frequently exposed to HIV, you may want to ask a health care provider about a Pre-Exposure Prophylaxis (PrEP) prescription. 

How do you take PEP? 

If you’re prescribed PEP, you must take PEP pills every day for 28 days (about four weeks). Failing to take all the pills or not taking them as prescribed can reduce its effectiveness. After you begin taking PEP, you’ll be asked to follow-up with a health care provider for HIV testing and other lab tests. The initial follow-up appointment typically happens immediately after you have completed the 28-day PEP cycle. Your health care provider may also have you complete a second follow-up appointment three months after the first follow-up appointment for more testing.  

What are the side effects of PEP? 

Some side effects of PEP include nausea, diarrhea, and bloating and may last the entire course of the PEP cycle. Reach out to a health care provider if your side effects bother you or don’t go away. 

To minimize these side effects, consider: 

• Taking PEP with at least eight ounces of water and food.  
• Not laying down within one hour of taking PEP.  
• Not taking PEP within two hours of consuming dairy products, antacids, and mineral supplements.  

What else is there to know about PEP? 

To avoid drug interactions with PEP, you may want to let a health care provider know about other medications you take. This includes over-the-counter or prescription medications, recreational drugs, and alcohol. 

PEP is safe to use during pregnancy and breastfeeding. 

PEP should not be used as HIV prevention and does not protect against pregnancy or other STIs. Because of this, while on PEP, continue other STI and pregnancy prevention practices, such as using a condom during penetrative sex and dental dams during oral sex.  

What forms of insurance coverage are there for PEP and Doxy PEP? 

Most health insurance plans cover PEP. If you’re unsure whether your plan covers PEP, reach out to your health insurance provider.  

If you don’t have insurance or your plan coverage is limited, you may consider using co-pay assistance and patient assistance programs to help pay for it.  

If you’re exposed to HIV through sexual assault, you may receive PEP at a free or reduced cost through the Office for Victims of Crime.