Jennifer Bofah, PharmD, RPh

Pre-exposure prophylaxis (PrEP) is an essential practice for HIV-negative patients who are considered high risk for the virus.

The high-risk group includes individuals who share needles or other drug injection equipment; have anal or vaginal intercourse with an infected partner, multiple partners, or a partner with multiple partners; have unprotected anal or vaginal intercourse; or have been diagnosed with a sexually transmitted disease in the past 6 months. PrEP is also safe and effective for women who are considering getting pregnant by a partner with HIV or who are breastfeeding.

PrEP is highly effective when taken as prescribed. The CDC reports efficacy of more than 99% in patients who engage in sexual intercourse and more than 74% in patients who inject drugs. Risk of contracting HIV can be even lower when combined with other prevention methods.

Prior to initiating any PrEP regimen, patients must undergo diagnostic testing to determine their current HIV status and other laboratory tests to identify health risks that may require close monitoring while on PrEP.

HIV status can be checked with an antigen/antibody test with a blood sample or an FDA-approved point-of-care fingerstick blood test. Laboratory antigen/antibody tests are preferred to the latter because of their sensitivity in detecting acute HIV infections. Patients must have HIV-negative results to initiate therapy.

Other clinical tests include a renal function test, hepatitis B virus (HBV) and hepatitis C virus screening, and a pregnancy test for women. Results from these tests can affect the use of PrEP medications.

The current standard practice for PrEP consists of two FDA-approved medications: Truvada and Descovy.

Truvada is recommended for all adults and adolescents at risk for HIV through sexual intercourse or injection drug use. Descovy, approved in October 2019, is also recommended for adults and adolescents at risk for HIV through sex, but excludes individuals at risk through vaginal intercourse.

Currently, Descovy has not yet been studied for HIV prevention in patients who engage in receptive vaginal sex. Some experts recommend Descovy only for men who have sex with men or who are at risk of renal dysfunction (CrCl 30 to <60mL/minute), osteopenia, or osteoporosis. Patients who test positive for HBV are also warned of the risk of having severe acute exacerbation of HBV once treatment of either medication is stopped.

Truvada and Descovy are each dosed as 1 tablet once daily. The most common adverse effects (AEs) include diarrhea, nausea, headache, and fatigue. These AEs typically go away with time and continual use.

It is important to note that participating in a PrEP regimen should be in conjunction with safe sex practices. This includes the use of condoms to reduce the risk of sexually acquired infections. Patients who participate in drug injections should also abstain from sharing needles and other injectable devices.

An initial visit between patients and their health care provider should include counseling on what PrEP medication is and how it works, the importance of adherence, potential AEs and management, safe sex, and sterile injection practices, as well as drug coverage through insurance or medication assistance programs such as “Ready, Set, PrEP.” Programs such as this offer coverage to individuals with a PrEP prescription who do not have health insurance for prescription drugs.

According to the CDC, PrEP is most effective after 7 days of continual use for receptive anal sex. For receptive vaginal sex and injection drug use, maximum protection is expected post 21 days of daily use. There are currently no data for insertive anal or vaginal sex.

Once PrEP is initiated patients are to follow up with their healthcare provider at least once every 3 months to repeat diagnostic tests (such as HIV, pregnancy test, STI in symptomatic patients). Patients should also receive continual counseling on possible AEs to encourage adherence to medications as well as safe sex and/or sterile injection practices. Other follow-up tests include kidney function tests in all patients and STI screening in symptomatic patients.

Individuals who may need to stop taking PrEP include those with reduced quality of life as a result of having severe AEs to the medications. Discontinuation is also recommended in cases of non-adherence or if patients’ HIV risk becomes low due to lifestyle changes. Patients may always reinitiate therapy if needed.

Although PrEP is highly effective when taken daily as prescribed, some health departments in the United States and health organizations in Europe and Canada are offering “on-demand” PrEP as an alternative. Also known as an “off-label” or “event-driven non-daily” use, studies have shown that the 2-1-1 schedule provides adequate protection for men who have anal sex with other men without use of a condom.

A “2-1-1” schedule is dosed 2 pills 2-24 hours before sex, 1 pill 24 hours after the first dose, and 1 pill 24 hours after the second dose. There are currently no data for “on-demand” PrEP for heterosexual men and women, transgender individuals, or individuals active with injection drug use. It is important to note that taking PrEP once daily is currently the only FDA-approved regimen for taking PrEP to prevent HIV in the United States.

It is recommended that women who are trying to conceive or are pregnant, postpartum, or breastfeeding begin PrEP therapy following an initial blood test for HIV as well as other diagnostic tests as mentioned previously. The drug of choice in this patient population is Truvada once daily.

According to CDC guidelines, patients of this population should continue therapy for at least 20 days to maximize prevention with PrEP therapy.

 Therapy should also be continuous thereafter.

Patients who become pregnant while on Truvada as PrEP should continue therapy throughout pregnancy. Risk and benefits of PrEP use should be discussed with the individual.

Individuals in each high-risk group must maintain medication adherence for optimal results in HIV prevention. Pharmacists play a vital role in this regard. They are known to increase the rate of adherence through patient counseling of medications, financial assistance in co-payment programs or medication assistance programs, and accountability through refill reminders for medications.

Thus, collaborative efforts between patients, physicians, pharmacists, and other essential personnel can further promote the effectiveness of PrEP regimens.

 is a supervising pharmacist for Community Care Specialty Pharmacy, which has offices in Hempstead, NY, and Totowa, NJ.

CDC. Pre-Exposure Prophylaxis (PrEP). Updated June 11, 2021. Accessed August 6, 2021. 

https://www.cdc.gov/hiv/basics/prep/prep-effectiveness.html

FDA. FDA approves second drug to prevent HIV infection as part of ongoing efforts to end the HIV epidemic. Accessed August 6, 2021. 

https://www.fda.gov/news-events/press-announcements/fda-approves-second-drug-prevent-hiv-infection-part-ongoing-efforts-end-hiv-epidemic

ClinicalInfoHIV. Recommendations for the use of Antiretroviral Drugs in Pregnant Women with HIV Infection and Interventions to Reduce Perinatal HIV Transmission in the United States. Updated December 29, 2020. Accessed August 6, 2021. 

https://clinicalinfo.hiv.gov/en/guidelines/perinatal/prep

Articles

Collaborative efforts between patients, physicians, pharmacists, and other essential personnel can further promote the effectiveness of PrEP regimens. 