Pre-Exposure Prophylaxis (PrEP)

What is Pre-Exposure Prophylaxis (PrEP) and how does it work? 

Pre-exposure prophylaxis, also known as PrEP for short, is a medicine that can prevent people from contracting HIV. This medication is taken by people who don’t have human immunodeficiency virus (HIV) but are at high risk for being exposed, or coming into contact with, the virus.  

PrEP blocks the enzymes, or proteins in the blood, that allow HIV to multiply. To block these enzymes, you must build up enough PrEP in your bloodstream. Once PrEP has reached a certain level in your bloodstream, it can prevent HIV from replicating in your body.  

Who can benefit from PrEP? 

You may benefit from PrEP if you test negative for HIV and meet any of the following conditions:  

• Have had anal or vaginal sex in the past six months, and you: 
  • Have a sexual partner with HIV. 
  • Don’t know your partner’s HIV status. 
  • Have multiple sexual partners. 
  • Engage in casual sex and don’t consistently use a condom. 
  • Have been diagnosed with a sexually transmitted infection (STI) in the past 6 months. 
• You inject drugs and: 
  • Have an injection partner with HIV. 
  • Share needles, syringes, or other injection paraphernalia. 
• You’ve been prescribed PEP (post-exposure prophylaxis) and you: 
  • Engage in behavior that could increase your risk. 
  • Have used multiple courses of PEP. 

List adapted from HIV.gov 

How do you take PrEP? 

PrEP can be taken as a pill form or as a bi-monthly injection. The United States Food and Drug Administration (U.S. FDA) has approved two types of pills to prevent HIV: Descovy and Truvada (sometimes prescribed as Emtricitabine-tenofovir). The FDA approved injectable form of PrEP is called Apretude. 

Daily PrEP in the form of a pill is taken as the name suggests, daily. A health care provider typically provides enough pills for three months, after which you will follow-up with the provider for routine testing and get a prescription refill for another three months. 

Injectable PrEP can be administered by a health care provider every two months. Along with bi-monthly injections, you will also receive follow-up testing.  

Both oral and injectable PrEP are available by prescription only. If you want to be prescribed PrEP, consider reaching out to a health care provider. They’ll work with you to decide which form of medication is best for you. 

What’s on-demand PrEP? 

On-demand PrEP, also known as intermittent-PrEP, or event-driven PrEP, is a non-daily dosing strategy of oral PrEP pills for those interested in HIV protection during a specific sexual interaction. Only Truvada has been approved for on-demand PrEP.  

On-demand PrEP pills are the same as daily PrEP pills just taken using a different schedule. Namely, you take on-demand PrEP for the individual occasions when you plan to engage in high-risk sexual behavior.  

You may consider using on-demand PrEP if you: 

• Only engage in anal sex. It’s important to note that on-demand PrEP has not been approved for vaginal sex and has only been studied among men who have sex with men (MSM) populations.  
• Frequently experience periods of sexual inactivity.  
• Use condoms in most but not all instances of sexual intercourse.  

Additionally, if cost is a barrier to taking on-demand PrEP, you may seek support through local, state, and federal assistance programs.  

How do you take PrEP on-demand? 

When it comes to dosing, on-demand PrEP follows a 2-1-1 schedule: 

• Take two pills 2 to 24 hours before sex. 
• Take one pill 24 hours after your first dose. 
• Take one pill 24 hours after your second dose. 

List adapted from WebMD 

If you’re interested in on-demand PrEP, you may consider speaking with a health care provider about whether this dosing schedule would be effective for you.  

Note: The FDA has only approved PrEP for daily pills or through a monthly injection and has not approved using PrEP for the 2-1-1 schedule. Additionally, the CDC doesn’t recommend the schedule. However, some providers still recommend it due to the efficacy displayed in PrEP studies and because it helps increase access to care. 

How effective is PrEP, and how fast does it work? 

When taken as prescribed, PrEP is highly effective at preventing HIV. Consistent and correct use of PrEP can prevent HIV contracted through sex by about 99 percent and HIV contracted through injection drug-use by at least 74 percent.  

There are certain factors that determine how fast PrEP works in the body, including the type of sex you have and if you’re an injection drug user. After you start PrEP, it may take up to 7 days for full protection in anal tissues and 21 days for protection in the blood stream and vaginal tissues. Consider talking with a health care provider about how long you’ll need to be on PrEP for it to reach full effectiveness and help you to get the most protection.  

Until your PrEP is fully effective at preventing HIV, you should continue to use other protective methods to reduce your risk of HIV, like condoms or knowing the HIV status of your partners.  

What are the side effects of PrEP? 

Side effects of PrEP may include nausea, diarrhea, headache, fatigue, dizziness, minor skin issues and stomach pain. These side effects usually aren’t serious and go away on their own over time. You can also reduce some of these side effects by eating nutrient-dense foods, getting plenty of sleep, staying hydrated, and being physically active. Avoiding things such as alcohol, caffeine, or foods that upset your stomach may also help. If you’re having issues with your skin, you can also avoid harsh ingredients, moisturize regularly, and use cool compresses.  

More serious but rare side effects include mild reductions in kidney function and bone density. Your health care provider should provide regular monitoring for kidney function during routine visits. If you’re at-risk for bone-related conditions, consider asking your health care provider if they recommend you using PrEP. It’s also worth noting that these side effects are reversible after stopping the medication.  

If your side effects don’t go away or inhibit your daily life, consider reaching out to a health care provider. 

PrEP pills are safe to use during pregnancy and breastfeeding; however, The FDA doesn’t recommend using PrEP injections during pregnancy and breastfeeding.  

What else is there to know about PrEP? 

PrEP doesn’t protect against pregnancy or other STIs. Because of this, while on PrEP, it’s important to continue other STI and pregnancy prevention practices. Consider using barrier methods such as condoms and dental dams for pregnancy and STI prevention and DoxyPEP for bacterial STI prevention. 

If you have a partner with HIV and are considering getting pregnant, you may consider reaching out to a health care provider to figure out the right PrEP plan for you. You can start taking PrEP pills one month before you start trying to get pregnant and can continue taking the pills through the first month of your pregnancy.  

If you breastfeed and you’re at high risk for HIV infection, you may consider taking PrEP pills while breastfeeding.   

What forms of insurance coverage are there for PrEP? 

Most health insurance plans cover PrEP free of charge. If you’re unsure about your plan’s PrEP coverage, you can reach out to your health insurance provider.  

If you don’t have health insurance or your plan is limited and you would like help paying for PrEP, there are co-pay and patient assistance programs including: 

• Drug Manufacturers Co-payment Assistance Programs 
• State PrEP Assistance Programs 
• Co-payment Assistance Programs for Accessing PrEP via Telemedicine 
• Patient Advocate Foundation 
• Patient Assistance Programs for Accessing PrEP via Telemedicine