Pre-exposure prophylaxis (PrEP) for HIV prevention is gaining traction as an important tool in the fight against HIV. Pharmacists are taking a role including and going beyond dispensing emtricitabine/ tenofovir disoproxil fumarate (Truvada, FTC/TDF) for PrEP. Important information for pharmacists about PrEP is discussed here.
Authored By: Ziad Nasr, Pharm.D., BCPS, BCIDP and Timothy P. Gauthier, Pharm.D., BCPS-AQ ID
[Last updated: 7 October 2019]
Human immunodeficiency virus (HIV) can lead to acquired immunodeficiency syndrome (AIDS) if left untreated. HIV typically weakens the immune system where the affected individual becomes prone to acquire other infections or infection-related cancers. HIV was first identified in the United States (US) during the mid to late 1970’s, and even though anti-retroviral therapy (ART) has advanced substantially since the FDA-approval of zidovudine (AZT) in 1987, a cure is still elusive.
Today every tool available is important towards limiting HIV transmission and Pre-Exposure Prophylaxis (PrEP) has emerged as one such tool. By taking PrEP as directed, individuals who are not infected with HIV but at-risk can reduce their chances of becoming HIV positive by 92-99%. Emtricitabine/ tenofovir disoproxil fumarate (Truvada, FTC/TDF) was FDA-approved for treatment of HIV in 2004, then years later in 2012 it was FDA-approved for PrEP. It remains the only FDA-approved medication for PrEP at the time of composing this article.
As medication experts, pharmacists play an important role in public health and can be advocates for safe and appropriate PrEP use. In this article, we identify five important things for pharmacists to know about PrEP. It should be noted that while we make an effort to touch on the main points, this is not meant to be an exhaustive review of PrEP and readers are directed to the links at the end of this article for additional information on the topic.
1. The only FDA-approved medication for PrEP is Truvada, but we expect Descovy to be FDA-approved sometime soon
**UPDATE: As of October 3rd 2019 FTC/TAF (Descovy) has been FDA-approved for PrEP in men**
FTC/ TDF is a combination pill of two anti-retrovirals which belong to the nucleoside reverse transcriptase inhibitor class. The pill can be taken with or without food and some of the more common side effects seen in PrEP trials were headache, abdominal pain, and weight decrease. FTC/TDF carries warnings for decreases in bone mineral density, lactic acidosis/ severe hepatomegaly with steatosis, and new onset or worsening renal impairment. FTC/TDF for PrEP is indicated to be taken once daily continuously while at-risk, but it is not recommended for patients with a creatinine clearance below 30 mL/min. As such, monitoring of serum creatine is indicated prior to therapy initiation and periodically during therapy. Some patients may experience mild side effects initially that subside after a few weeks of therapy.
Descovy (emtricitabine/ tenofovir alafenamide, FTC/ TAF) was FDA-approved in 2016 for the treatment of HIV and is similar to FTC/ TAF, with the formulations of tenofovir being the difference. Comparing TDF to TAF, TDF is a prodrug that gets converted to tenofovir in the plasma and then enters the HIV target cell, while TAF is a prodrug with 91% less circulating tenofovir plasma concentrations. Thus, the use of TAF notably reduces the risk of kidney injury and BMD losses in comparison to TDF.
In April 2019 Gilead submitted a supplemental new drug application to the FDA for once-daily FTC/ TAF for PrEP. It was submitted with a priority review voucher and we expect an FDA decision by late-2019. The application was based upon findings from a phase 3 study entitled DISCOVER, which compared FTC/ TDF versus FTC/TAF in men and transgender women who have sex with men at high-risk for sexually acquired HIV. Results from DISCOVER were presented in March 2019 at the Conference on Retroviruses and Opportunistic Infections (CROI), which was held in Seattle, WA.
2. PrEP is not a set it and forget it scenario
Prior to initiating PrEP CDC recommends an assessment of renal function, HIV status, presence of sexually transmitted infections (symptoms and testing), medication adherence counseling, behavioral risk reduction support, and safety monitoring.
After PrEP is initiated, monitoring frequency varies a bit by item, but most require an assessment at least every 3 months. The CDC provides a list of monitoring recommendations in their PrEP Clinical Practice Guideline here. Having to be screened, counseled or physically assessed so frequently can be a challenge for some patients and providers.
If a patient becomes HIV positive while on therapy then PrEP should be discontinued, since prevention is no longer the goal. If a patient on PrEP ceases their at-risk behavior (e.g., stops being sexually active), PrEP should be discontinued since it will not provide any benefit. It can be re-started at a later date should the at-risk behavior resume.
Other follow up tests recommended include: oral/rectal STIs assessment for men who have sex with men; pregnancy intent assessment and pregnancy testing every 3 months for heterosexuals, and access to clean needles/ syringes plus drug treatment services for people who inject drugs.
Pharmacists can play an important role in encouraging and assisting patients to comply with monitoring for PrEP.
3. Adherence and safety counseling for patients on PrEP is very important
PrEP is much less effective if not taken consistently. It has to be taken as prescribed. Also, combining PrEP with safer sex practices (e.g., condom use or other preventative methods) lowers the risk for acquiring HIV even more. In fact, the estimated annual incidence of new HIV infections in the US has significantly declined from 2008 until 2014 (18%) among whites, young gays and bisexual men. However, this progress has been uneven and offset by increased infections in other age groups (e.g., 25-34 years old) and ethnicities (e.g., latinos).
As medication experts and trusted healthcare professionals, pharmacists are known to be able to develop good rapport with HIV patients, enhance patient understanding, support medication adherence, promote risk reduction counseling, and are well positioned to play a key role in addressing current opportunities in PrEP prescribing patterns while working closely with other members of the multidisciplinary healthcare team. Moreover, pharmacists are well equipped to properly manage PrEP utilization, side effects and drug-drug interactions. Pharmacists should also educate themselves about PrEP and be proactive about medication therapy management. Pharmacist roles continue to evolve and expand in public health, and continuing education for pharmacists remains crucial to further improve their knowledge, competencies, and advocacy for both disease prevention and management.
In recent years there has been more literature on the role of pharmacists and PrEP. Pharmacists are now prescribing PrEP, monitoring PrEP, and overseeing PrEP programs. Pharmacists have the potential to extend the workload capacity of our physician counterparts through collaborative practice and it is happening to help PrEP become more available. For more on this topic we recommend this article which explores the pharmacist’s expanding role in PrEP.
Related to adherence it should be noted that PrEP on-demand has been studied, in which a patient takes two pills 2-24 hours before sex, a third pill 24 hours after the first drug intake, and then a fourth pill 24 hours later. This PrEP strategy has yet to gain support seen with continuous PrEP and data from a trial exploring PrEP on-demand are available here.
4. There are stigma associated with HIV and PrEP
For many years there has been stigma and discrimination impacting the lives of those living with HIV. For example, in a recent study published in 2015 it was found that these two factors can hinder patients from receiving treatment. There may be some parallels with PrEP.
Pharmacists should be aware the PrEP is not synonymous with a license to have unprotected sex or participate in risky behaviors. To ensure patients understand that PrEP must be used responsibly to be most effective, pharmacist counseling is important. Patients on PrEP should be informed that it will not prevent sexually transmitted infections and that PrEP is not a replacement for condoms.
Regardless of how homosexuality is viewed by an individual, it is undeniable that PrEP can prevent the spread of HIV when used appropriately in at-risk individuals, which can be very important for public health. Some providers even feel that regardless of condom use, for the sake of public health, PrEP should be provided to those at risk if the patient is willing to be take it consistently. Ultimately a combination of factors including input from policy makers, providers, and patients will direct the availability of PrEP.
Note too that PrEP is not just for sexually active homosexual men. Here are two tables from the CDC guidelines regarding who qualifies for PrEP, see the guidelines for a complete description…
5. PrEP can be very expensive
Some insurance plans or state health department initiatives may provide coverage for FTC/ TDF, but without such support PrEP may be beyond reach for those without the resources to procure it.
Consistent with many other resources, GoodRx.com reports it is $1,748.72 for a 30 day supply of FTC/ TDF. That comes out to $58.29 per pill!
Closing comments
Pharmacists have a clear opportunity to play an important role in promoting the safe and effective use of PrEP, which can support important public health efforts to reduce HIV transmission. While the fight against HIV continues, PrEP remains an important tool to be aware of.
SUGGESTED READINGS
RECOMMENDED RESOURCES
- CDC PrEP Website
- AETC PrEP Pocket Guide for providers
- AETC PrEP Webinar
- UCSF PrEP Guidelines and Resources
- Florida Department of Health PrEP Page
- PrEPfacts.org
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