Switch On Your HIV Smarts.

PrEP: Your Burning Questions Answered

, by Megan Canon, MPH


Dr. Albert Liu

We know people have a lot of questions and concerns around PrEP. We enlisted Albert Liu, MD, MPH, from Bridge HIV at the San Francisco Department of Public Health, to answer common PrEP questions we’ve heard and help sort out what we know and what we don’t know about this new HIV prevention strategy.

What are the side effects from Truvada for PrEP?

Truvada is a safe and well-tolerated drug. About 1 in 10 people in PrEP studies reported they had nausea, stomach pain, or weight loss when they first started taking Truvada. In most people, these side effects improved or went away after taking Truvada for a few weeks.

A small number of people had a decrease in kidney function that returned to normal when they stopped taking PrEP. It is important to have regular blood tests to monitor your kidney function while taking PrEP. Small losses of bone density (thickness) have also been seen in people taking Truvada; however, these changes have not been associated with an increase in bone fractures.

With all medications, it’s important to weigh potential side effects with potential benefits from taking the medication. In terms of potential benefits, when PrEP is taken daily, it can significantly reduce your chances of getting HIV infection. We’ve also heard from a number of people taking PrEP that they have less anxiety and worry about HIV. It is helpful to discuss these considerations with a health care provider who can help you decide whether PrEP is right for you.

If I start PrEP, can I stop using condoms?

Condoms have been and continue to be an effective tool in reducing HIV risk. They are also the only tool that protects against both HIV and certain other sexually transmitted infections (STIs) and prevents pregnancy when used correctly and consistently.

For people who do not use condoms every time they have sex, PrEP can provide an effective layer of protection against HIV. In the iPrEx study of gay/bi men and transgender women, PrEP was found to reduce almost half of HIV infections overall, and among those who took PrEP consistently and had Truvada detected in their blood, it is estimated that PrEP was over 90% effective in preventing HIV infections.

Using condoms correctly and consistently while taking PrEP will provide the maximal protection against HIV and STIs. The choice to use condoms, like the choice to use PrEP, is a personal decision. The important thing is to find an HIV prevention strategy that fits yours needs and meets your sexual health goals.

Won’t people start having “riskier sex” when they begin taking PrEP? If more and more people start using PrEP, won’t the rate of STIs go up?

Concerns have been raised that the use of PrEP will lead to increases in sexual risk taking (risk compensation). In the iPrEx study, participants who believed they were taking Truvada for PrEP did not increase their sexual risk behavior, and rates of syphilis infection went down.

It’s important to note that during the study, participants didn’t know whether Truvada as PrEP was effective in preventing HIV or whether they were getting Truvada or a placebo (dummy) pill. PrEP demonstration projects are currently underway to evaluate whether sexual behaviors change in people taking PrEP in the “real-world,” and will also help determine how to best deliver PrEP in different settings. It’s recommended that all men who have sex with men, including those taking PrEP, get screened for STIs every three to six months.

If my HIV-positive partner has an undetectable viral load and I’m HIV-negative on PrEP, can I stop using condoms?

Kudos to your HIV-positive partner for taking HIV medications to stay healthy and to reduce the chances of passing the virus to you by being undetectable. And kudos to you for being proactive about your sexual health and taking PrEP to further reduce your own HIV risk.

Your partner being undetectable significantly reduces your risk for HIV, assuming there are no other sexl partners in your relationship and you and your partner do not have a sexually transmitted infection. Being undetectable or taking PrEP does not protect you against STIs like gonorrhea or syphilis, or prevent pregnancy. Condoms further reduce your HIV risk as well as your risk for other STIs. Medication adherence (taking HIV medications on a daily basis) is important for remaining undetectable for your HIV-positive partner, and adherence to PrEP is important for it to be effective in reducing your risk of getting HIV.

If you are considering adding or removing condoms and/or PrEP from the equation, it is important to be informed about these issues and to discuss them with your partner and your medical provider. Ultimately, the decision to use condoms, as is the decision to use PrEP and take HIV medications, is between you and your partner.

How soon will PrEP become protective after I start taking it?

Preliminary studies suggest that when starting PrEP, it may take at least seven days of taking daily Truvada for PrEP to reach substantial levels of protection. However, further studies are needed to confirm these findings. Also, only daily PrEP has been shown to be effective; at this point, there’s no evidence in humans that taking PrEP just before sex or just before and after sex will be protective, and there’s some evidence that it may not be effective.

It is important to take Truvada consistently every day because your level of HIV protection from PrEP may decrease with missed doses of the medication. However, we know people aren’t perfect, and if you accidentally miss a dose, it’s not the end of the world, as PrEP affords some wiggle room. If this happens, it is recommended to resume your regular pill-taking schedule. If you stop taking PrEP for more than seven days and want to restart taking PrEP, it’s important to see your provider and get an HIV test before restarting PrEP to minimize the risk of developing drug resistance. If you became HIV infected during this period and then restarted PrEP, there is a risk of HIV developing resistance to Truvada.

What are the chances of developing drug resistance?

If you are already infected with HIV while starting or taking PrEP, there is a risk of the HIV in your body developing resistance to Truvada. This means that certain medications may no longer work when used as HIV treatment. Truvada contains two anti-HIV drugs (tenofovir and emtricitabine) and is effective in preventing HIV in HIV-negative people as PrEP but is not sufficient for treating HIV infection in HIV-positive people (this requires three or more anti-HIV drugs used in combination).

Therefore, it is important to see your provider and have testing done to make sure you are HIV-negative before you start using this HIV prevention strategy, and to be re-tested before re-starting PrEP if you’ve been only taking PrEP off and on. It’s also important to take PrEP consistently and correctly to minimize the chances of becoming infected and subsequently developing resistance to Truvada.

What if I decide that I don’t want to take PrEP anymore? How can I stop it safely?

We recognize PrEP is not meant to be taken for the rest of your life. If you decide PrEP is no longer a useful HIV prevention strategy for you, we recommend you discuss this with your medical provider before stopping PrEP. It is helpful to discuss how your sexual behaviors or relationships may have changed, and also the last time you had sex.

You may be advised to continue taking PrEP for four weeks after your last potential exposure to HIV, as this is the recommendation for post-exposure prophylaxis (PEP), where individuals take anti-HIV medications for 28 days after a significant HIV exposure. This period also provides some planning time to transition to other HIV prevention strategies.

If I’m taking PrEP and have condomless sex with an HIV-positive partner, can I potentially expose my next HIV-negative partner to the virus from the previous HIV-positive partner?

You cannot serve as a type of “pass-through,” where you carry HIV from one partner to another while staying uninfected yourself. However, if you were to become HIV infected while on PrEP (either because you weren’t taking it consistently, or if PrEP were not 100% protective), then you could potentially pass HIV on to HIV-negative partners. Getting tested regularly for HIV is an important part of taking PrEP to ensure that you remain HIV-negative, and as described above, to minimize the risk of developing HIV resistance if you become infected.

If an HIV-negative person taking PrEP has condomless sex with an HIV-positive person who doesn’t have an undetectable viral load, where does the virus go?

Truvada for PrEP works by blocking an enzyme called HIV reverse transcriptase. By blocking this enzyme, it prevents HIV from making more copies of itself in the body. Without the ability to replicate, the virus is unable to take hold and is cleared from the body. It’s important to remember, though, that PrEP may not be 100% effective in preventing HIV.

Am I protected by PrEP if my HIV-positive partner is resistant to Truvada?

As Truvada contains two medications (emtricitabine and tenofovir), it is important to consider whether your HIV-positive partner has resistance to one or both medications in Truvada. In animal studies, Truvada was effective in preventing infections with a virus that was resistant to emtricitabine alone. However, there was reduced protection with Truvada PrEP in cases of tenofovir resistance. Fortunately, resistance to tenofovir is still relatively uncommon in the community. As we don’t know whether results seen in monkey studies will apply to people, additional studies in humans are needed to address this important question.

I talked to my doctor about PrEP and they won’t prescribe it to me because they don’t know what it is. What can I do?

We’ve unfortunately heard many stories from the community where providers are resistant to providing PrEP for a number of reasons. If you’re having trouble with your doctor being “PrEP-friendly,” then we recommend taking these steps to become an informed consumer and go back to your doctor:

  1. Print and review the CDC brochure “How to talk to your doctor about PrEP.”
  2. Print and bring with you the CDC interim PrEP guidelines to show your doctor.
  3. Gilead has medication assistance programs available to help make Truvada more accessible. If you don’t have health insurance, you can bring this enrollment form with you to your provider to talk about costs and see if you are eligible. If you already have health insurance, you can take sign up for a Gilead Co-Pay Coupon Card at your pharmacy to save up to $200 on your drug copay.
  4. Do your homework and check out PrEPfacts.org, My PrEP Experience blog and Project Inform, and even the PrEP Facts Facebook group for information and support. For PrEP Facts, we’ve developed many print materials including a new brochure featuring billing codes and PrEP protocols that may be helpful for your provider.

I want to go on PrEP but I don’t have health insurance or a doctor. What’s the first step I should take?

To get Truvada for PrEP, you will need a prescription from a medical provider, so your first step is to make an appointment at a health center or clinic that has primary care and/or sexual health services and accepts patients without insurance. In selecting a clinic, you may want to ask whether they have providers who are able to prescribe PrEP and are open to discussing PrEP with their patients. Doctors, nurse practitioners, and physician assistants are all qualified to write PrEP prescriptions.

If you are uninsured, now is a great time to get coverage. The Affordable Care Act (AKA “Obamacare”) requires that all US citizens have insurance. Depending on your income, you may be eligible for Medicaid, or you may be able to purchase insurance through an online marketplace. (In California, this marketplace is called Covered California; if you live outside of California, visit Healthcare.gov.) Depending on your individual circumstances, you may be able to get insurance now, or may need to wait for the next enrollment period to open. When choosing a plan, you’ll want to consider whether Truvada for PrEP is covered by the plan and at what cost (i.e., what the co-pay is for Truvada).

Here is a step-by-step checklist of what you need to make your appointment.

  1. If you are uninsured, visit CoveredCA.com (if you live in California) or Healthcare.gov (if you live outside of California) to learn more about getting coverage.
  2. Make an appointment to get PrEP at a health center that has primary care/sexual health services and accepts patients without insurance (or accepts your insurance if you are insured).
  3. Ask for a sexual health check-up and an evaluation for PrEP. Set up a reminder so you don’t miss the appointment.
  4. Do your homework: Check out the CDC’s brochure “How to talk to your doctor about PrEP,” PrEPfacts.org, My PrEP Experience blog, and Project Inform, and even the PrEP Facts Facebook group for information and support.

Accessing PrEP is a process. It may take a few weeks to months to process any required paperwork and have baseline lab tests performed prior to getting a prescription for PrEP.

My HIV-positive partner is taking HIV medications to treat his/her HIV. Will my Truvada for PrEP interact with the HIV medications he/she is taking?

No, your PrEP medication will not interact with the HIV medications that your HIV-positive partner is taking. The anti-HIV medications you are taking work to help prevent HIV infection in your body and nobody else’s, and vice versa. Even if your HIV-positive partner is taking Truvada, it is important not to share your PrEP with your HIV-positive partner or to take your partner’s HIV medications as PrEP.  It’s easy to mix up pills, and this could lead to unexpected allergic reactions or side effects, or you or your partner might run out of medications when you need them.

Is it safe to take PrEP after I’ve been drinking?

Yes, it is safe to take Truvada after a night on the town. Truvada is not known to interact with alcohol or other recreational drugs in harmful ways. Continuing to take PrEP daily while drinking or using recreational drugs and having sex may help provide protection from HIV during these periods.

How do I know if the pill I’m taking is working?

Many people don’t feel any different while taking PrEP. It doesn’t mean that the medication isn’t working. If you’re taking PrEP correctly and consistently, you can be confident that the drug is working to help protect your body from HIV infection.

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Megan Canon, MPH, is the social marketing manager for San Francisco AIDS Foundation and the founder of PrEPfacts.org.


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