How to Prescribe PrEP in Primary Care

Neil Skolnik, MD; Christopher M. Bositis, MD


July 19, 2022

This transcript has been edited for clarity.

Neil Skolnik, MD: I'm Dr Neil Skolnik. Today, we're going to talk about the 2021 update on preexposure prophylaxis for the prevention of HIV (PrEP). It's a critically important topic for all of us to understand. Joining me today to discuss this is Dr Chris Bositis, who is a family physician and HIV specialist and the clinical director of the National Clinician Consultation Center at University of California, San Francisco, which runs the PrEP warmline. His clinical practice is currently in Greater Lawrence Family Health Center in Lawrence, Massachusetts. Chris, welcome to Medscape.

Christopher M. Bositis, MD: Thanks, Neil. Glad to be here.

Skolnik: Can we start by just defining what PrEP is and how well it works?

Bositis: Sure. PrEP, quite simply, is an HIV prevention method whereby somebody who does not have HIV takes a medication to reduce their risk of acquiring it if they're exposed to the virus. It's highly effective with estimates for reducing the risk for sexual transmission of HIV as high as 99% and around 75% for reducing the risk for HIV transmission through injection drug use.

Skolnik: That degree of effectiveness is fantastic. Is it something that most of us in primary care should be able to prescribe?

Bositis: Absolutely. The newest prep guidelines are really straightforward, and I think that PrEP prescribing is well within the scope of practice for all primary care clinicians.

Skolnik: If we're going to prescribe it, we need to think of it. Who is eligible?

Bositis: A lot more people than we realize, with current estimates by the CDC indicating that as many as 1.2 million people in the United States have some indication for PrEP use. Unfortunately, not everybody who could benefit is actually taking it. The rates of PrEP uptake are lowest for people of color, women, and those who inject drugs. So to try to address some of these inequities, the CDC recommends that clinicians talk to all sexually active adolescents and adults about PrEP and that they prescribe it to anyone who requests it, even if no specific risk factors for HIV acquisition are identified. For people who report having vaginal or anal sex, PrEP should be offered if:

  • They report having a sexual partner with HIV, particularly if that partner has a detectable HIV viral load;

  • If their viral load is not known or if the person has been diagnosed with a bacterial sexually transmitted infection (STI) in the past 6 months; or

  • If they report having one or more sexual partners whose HIV status is unknown and they also report inconsistent or no condom use. This third indication is really the broadest, and it's the one that's most underappreciated by most clinicians.

For people who inject drugs, PrEP should be offered if they report an injection partner with HIV, sharing injection equipment, or any sexual risk factors for HIV acquisition as well.

Skolnik: This is something that we should be thinking about pretty frequently. Can you go over the FDA approved medications for PrEP?

Bositis: Sure. There are three. The first is commonly referred to as F/TDF [emtricitabine/tenofovir disoproxil fumarate], or brand-name Truvada. This is an oral medication that is FDA approved for all adults and adolescents with any risk for HIV acquisition. It should not be used in people whose creatinine clearance is < 60 mL/min, and it also has a small and reversible risk for a decrease in bone mineral density. The second is commonly called F/TAF [emtricitabine/tenofovir alafenamide], or brand-name Descovy. This is basically a newer form of TDF, which has a lower risk of bone and renal toxicity but does have a slightly higher risk of weight gain and lipid abnormalities. It is FDA approved for men and transgender women with sexual risk for HIV acquisition. Lastly is cabotegravir, which is the newest FDA approved medication for PrEP. It's injectable and it is approved for all adults and adolescents with any sexual risk for HIV acquisition.

Skolnik: How are the medicines dosed?

Bositis: The oral forms of PrEP (F/TDF and F/TAF) are typically taken as one pill once a day. Truvada is also approved for intermittent dosing in people who report less frequent sexual risk or sexual exposure to HIV. For those folks, the dosing is called 2-1-1, where two pills are taken between 2 and 24 hours before the planned sexual activity and one pill taken 24 hours after the first dose and then one pill taken 24 hours after the second dose. For the injectable cabotegravir, the injections are monthly for the first 2 months and then every 2 months thereafter.

Skolnik: So we have a discussion with the patient. We decide with them that they want to start PrEP. Are there any labs we need to check before prescribing the medicines?

Bositis: Yes, absolutely. All people need to have baseline HIV testing before starting PrEP. In addition to that, hepatitis B testing and screening for syphilis should be done. Site-specific screening for gonorrhea and chlamydia is also recommended, and for people who will be taking oral PrEP, baseline renal function should be assessed with the creatinine level.

Skolnik: So now we've prescribed the medicine. What is the recommended follow-up?

Bositis: For people who are taking oral PrEP, it's recommended that HIV testing be repeated every 3 months and that STI screening be repeated every 3-6 months. Renal function monitoring should be done with serum creatinine at least yearly and more often for people who are older or who have risk factors for progression to chronic kidney disease (CKD). For people who are using the injectable form of PrEP, HIV testing should be done at the time of each injection and STI screening should be repeated every 2-4 months according to the most recent guidelines.

Skolnik: Chris, this is incredibly helpful, and you've made it something that we can implement in primary care. If our listeners have additional questions as they're thinking about this and seeing patients, what resources are available for us?

Bositis: The first resource that I would recommend is the CDC website. The PrEP guidelines are readily available there. For folks who have questions about patients they're seeing in their clinical practice, I would also recommend calling us at the National Clinical Consultation Center (NCCC) on the PrEP warmline: (855) 448-7737. Our website is We'd be happy to help you with any clinical questions that might arise.

Skolnik: Chris, I appreciate your joining us today.

Bositis: Thanks so much, Neil. It's been my pleasure to be here.

Skolnik, MD This is important information on a critically important topic. I'm Dr Neil Skolnik, and this is Medscape.

Neil Skolnik, MD, is a professor of family and community medicine at the Sidney Kimmel Medical College of Thomas Jefferson University and associate director of the Family Medicine Residency Program at Abington – Jefferson Health. He has published over 350 articles, essays, poems, and op-eds in the medical and nonmedical literature, as well as four medical textbooks and a book of short stories. In addition, he is the host of the American Diabetes Association's monthly Diabetes Core Update podcast. Follow him or direct-message on Twitter: @NeilSkolnik

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