PrEP Facts: Introduction & FAQ

Learn more about Pre-Exposure Prophylaxis (PrEP) and how this HIV prevention strategy may be useful for you or someone you know.

PrEP Facts: Introducción y Preguntas frecuentes [Spanish]

PrEP, or pre-exposure prophylaxis, is a prescription medicine that you take before you come in contact with HIV that will prevent HIV infection. There are a few medications approved for PrEP: Truvada, Descovy, a generic version of Truvada, and an injectable medication named Apretude. These medications are highly effective when taken as prescribed, and are very safe and generally well-tolerated by most people.

Anyone can use PrEP to prevent HIV infection. If condoms aren’t or can’t be used during sex, or if using clean syringes is not possible, then taking PrEP is an effective way to help prevent HIV. PrEP does not prevent other sexually transmitted infections (STIs) or pregnancy.

In this series of articles we’ll introduce you to the basic facts about PrEP:


Frequently asked questions about PrEP

Is it safe to drink alcohol while taking PrEP?

There are no known interactions between the two. Taking PrEP outside the times you drink can help you avoid missing doses.

Can I use drugs when taking PrEP?

Recreational drugs are not known to interact with either Truvada PrEP or Descovy PrEP. Both medicines belong to a class of HIV meds called NRTIs that generally do not interact with drugs such as marijuana, cocaine, or MDMA. Search the HIV Drug Interaction website for more information.

My partner is on PrEP. Can they be a “bridge” to HIV infection if they have sex with someone who is HIV-positive?

No cases of this kind of transmission have been reported. PrEP stops HIV from reproducing in the body, so it can’t establish an infection and eventually dies. If your partner has sex with someone living with HIV with a detectable viral load, they will not pass on HIV to you.

Should I tell people in my life that I’m taking PrEP?

One thing you may want to think about before starting PrEP is what might happen if your friends, family, or sex partners find out you’re taking it. Hopefully, their response is supportive. After all, you’re taking proactive care of your sexual health and helping stop HIV!

Still, some may assume you have HIV because they don’t know Truvada or Descovy can be used as PrEP. Even if they know about PrEP, they still may not approve of it. These judgments can strain personal relationships, especially if a sex partner shames people who take PrEP.

Take some time to think about who you trust and feel safe (emotionally and/or physically) telling that you use PrEP. Think about who might see you taking PrEP, see your pill bottle, or notice your medical visits. Consider the range of reactions you might get and how you might respond. Taking PrEP is nothing to be ashamed of, but neither is keeping it private.

What should I do if my healthcare provider doesn’t want to prescribe PrEP?

Some clinicians are not aware of PrEP, may be unwilling to prescribe it, or may not be comfortable discussing sexual health. You may need to find another provider to prescribe PrEP and work with you on your sexual health goals. If your provider is willing to prescribe PrEP but needs guidance about how to support you, they can contact the Clinicians Consultation Center or consult the federal PrEP guidelines.

Is PrEP safe?

Yes. Both Truvada and Descovy have been prescribed and used globally for many years. Not only is PrEP safe for most people to use, we also know how to screen for health issues that may occur in some people while they use either medicine.

Can young people take PrEP?

Young people under age 18 can take PrEP. However, there are some things that healthcare providers look out for if a young person is taking PrEP.

Significant bone growth happens during teen years and young adulthood. Truvada can cause minor decreases in bone tissue in some people (around 1% in youth). This change is not clinically significant, and there is no indication that Truvada use will impact bone health over time.

Younger people may need additional support around adherence. You may want to try more than one kind of reminder to help you take your PrEP as prescribed while also juggling school activities, working, coping with stigma, and dealing with pressures from peers and family. For more information, read PleasePrEPMe’s youth page.

If I’m on someone else’s insurance, will they know I’m taking PrEP?

If you live in California and are on someone else’s health plan, such as a parent’s or guardian’s, you can request that your health plan keep your medical care reports private. Go to My Health Info and follow the easy steps. Similar protections may be available in other states.

The details of any medical services you receive (such as PrEP or HIV testing) will not appear on the plan’s statements. However, other details (like the deductible cost for those services) may reflect a change if you paid a copay. This may get the policy holder’s attention, especially if you’re seeing your doctor quarterly for PrEP. Consider how this may affect your relationship with the policy holder.

In California, minors can legally seek sexual health services, including PrEP care, without a parent’s consent or notice. This includes not disclosing sensitive information to parents or guardians without the minor’s consent. However, laws vary widely in other states around minors, confidentiality, parental consent, and insurance plan billing, so make sure you know the laws in your state.

I’m traveling and I am running out of PrEP. What can I do?

First, you need to find a clinician who can prescribe it; and second, you’ll need to figure out how to pay the related costs.

The best bet would be to seek a local sexual health clinic that provides PrEP. Find out more info about the walk-in PrEP services offered at Strut, or email for help. A second option would be to contact a telehealth service.

Travel insurance probably won’t cover the costs, although international work insurance or insurance from a US-based employer may. If you don’t have those, you may have to cover the costs out of your own pocket.

What’s the difference between PrEP and PEP?

PrEP is taking two HIV medicines before exposure to HIV. PEP (or post-exposure prophylaxis) is taking three HIV medicines after an exposure to HIV.

If you are not taking PrEP and you think you were exposed to HIV, then you may want to consider taking a course of PEP. PEP involves starting HIV medicines within 72 hours of the exposure and taking them for 28 days to reduce the risk of infection. The sooner PEP is started, the more effective it is likely to be.

Sometimes people think they should take PEP while they’re on PrEP. This isn’t necessary if you’ve been taking PrEP as prescribed and have not missed doses. If you have missed doses—especially if you’re taking PrEP 2-1-1—and you think you’ve been exposed to HIV, then consult with your provider immediately about PEP.

If you have completed a course of PEP and a 4th-generation HIV test comes back negative, you can transition from PEP to PrEP without interruption, if you want.

What happens if I forget to take a dose of daily PrEP?

If you forget to take a dose of daily PrEP, take it as soon as possible if it’s within the first 12 hours. If it’s beyond that, wait and take the next dose as usual. There’s no need to double-dose.

Further, if you only have anal sex while using daily PrEP, it’s OK to miss a dose here or there. PrEP drugs stay in rectal tissue longer than in vaginal and front hole tissue. If you have vaginal or front hole sex, it’s more important not to miss doses to keep optimal protective drug levels in those tissues.

If you had sex while using PrEP 2-1-1 and missed a dose, contact your healthcare provider promptly for advice and next steps.

Also, make sure you keep going to your quarterly visits and refill your PrEP supply on time. If you change insurance, check your health plan’s coverage ahead of time so you can troubleshoot any issues before going to your next PrEP visit or pharmacy pick-up.

Can I take PrEP with erectile dysfunction drugs like Viagra or Cialis?

There are no known interactions between PrEP drugs and erectile dysfunction drugs such as sildenafil (Viagra) or tadalafil (Cialis).

Can I take PrEP if I'm using nutritional supplements or protein/creatine powders?

Tell your PrEP provider if you use protein or creatine powders for weight training or as nutritional supplement. These can impact the results of blood tests that check your kidney health.

Does PrEP interact with other medications?

The good news is that PrEP meds generally have few interactions with other drugs. Consult your provider, a pharmacist, or the HIV Drug Interactions website for more information on possible interactions between your PrEP medicine and any prescription and non-prescription medicines and nutritional supplements you take.

Some drugs that move through the kidneys may increase the blood levels of PrEP drugs. These include high-dose or multiple NSAIDs (aspirin, ibuprofen, naproxen, etc.); acyclovir and valacyclovir; and certain antibiotics (amikacin, gentamicin, neomycin, streptomycin, tobramycin). If you’re treating symptoms of a cold or the flu, check the ingredients of any over-the-counter medicine you take.

Does PrEP ever fail at preventing HIV transmission?

PrEP is very effective at preventing HIV, but it’s not 100% protective. A handful of HIV transmissions have been reported worldwide since 2012 in people who were taking PrEP consistently and as prescribed. All were in men who have sex with men.

In most of these cases, a resistant form of HIV was transmitted that dodged the protective effects of the two drugs in PrEP. In another case, a virus that was sensitive to both drugs was transmitted. All of the men were quickly connected to HIV care and are doing well with suppressed viral load.

It’s important to understand the decisions you make to use various prevention tools. Oral contraceptives do not prevent all pregnancies, and flu vaccines don’t prevent every case of influenza each winter. Similarly, using condoms doesn’t prevent every HIV transmission. Although rare infections are possible, PrEP is still highly effective at preventing HIV when taken correctly.

Is PrEP safe to take if I have hepatitis?

Before starting or restarting PrEP, your healthcare provider will want to know if you have hepatitis A, B, or C. You can get vaccinated to prevent two of them (A & B), and you can be treated for two of them (B & C). Hepatitis B screening is included in PrEP care. It’s important to get screened for these depending on your likelihood of exposure.

HEPATITIS A: This virus is usually transmitted by consuming food or water that’s contaminated with feces. Uncooked shellfish can also be the cause. Although it rarely causes liver failure, hepatitis A can cause severe disease. Consider getting the vaccine if you haven’t already had hepatitis A.

HEPATITIS B: This virus is usually transmitted through sex or exposure to infected blood, such as sharing needles, unsterilized tattoo tools, or during childbirth. Most people clear the infection on their own but some have lifelong (chronic) disease. Consider getting the vaccine if you haven’t already had hepatitis B.

If you have chronic hepatitis B, stopping PrEP medicines can impact it. That’s because PrEP drugs are also used to treat hepatitis B: If you stop PrEP, it can cause the virus to flare up in the liver. It is safe to take PrEP with chronic hepatitis B, but make sure your doctor monitors your health more closely if/when you decide to stop PrEP. People with chronic hepatitis B should only use daily PrEP, not 2-1-1.

HEPATITIS C: This virus is spread by blood-to-blood contact, mostly through sharing needles, unsterilized medical or tattoo equipment, and needle stick accidents. Sexual transmissions have occurred among gay men, likely due to micro-tears during anal sex. Emerging data suggest that PrEP users may be at higher risk for contracting hepatitis C through sexual transmission. Hepatitis C testing is recommended when starting PrEP, and your provider may suggest regular testing.

There is no vaccine for hepatitis C, but several different treatments can cure it. Some hepatitis C medicines may increase the blood level of tenofovir in PrEP, so be sure to discuss this with your provider if you are considering hepatitis C treatment. Lastly, be aware that you can get hepatitis C again after being treated for it.

What new forms of PrEP are being studied?

An exciting field of clinical research is looking at different ways that people can take PrEP. These include oral pills, injections, vaginal rings and films, vaginal and rectal gels, enemas, skin patches, and implants.

Some studies are combining HIV with STI prevention, while others are including contraception options. For more information, go to AVAC’s website.

PrEP Facts content written by Alan McCord and Reilly O’Neal. Medical review by Janessa Broussard, RN, MSN, AGNP-C, vice president of medical affairs at San Francisco AIDS Foundation.