What are the indications for PrEP?
Patients in whom PrEP is indicated include sexually active adults and adolescents (> 35 kg)19 whose use of a condom is inconsistent or who have had multiple recent sex partners; those with a recent bacterial STI; and men or women with a sexual or injection partner known to be HIV-infected (TABLE 2).15
What steps should be taken before and after initiating PrEP?
Providing PrEP is a harm-reduction strategy similar to prescribing other common preventive medications, such as statins to reduce hyperlipidemia and prevent myocardial infarction; oral contraceptives to prevent unwanted pregnancy; and metformin to prevent complications of diabetes. There are a few screening criteria prior to initiating PrEP (TABLE 3)10:
- A patient starting PrEP should be (1) HIV-negative, ideally screened by a laboratory-based antigen–antibody (ie, fourth-generation) HIV test or HIV RNA test, and (2) without symptoms of acute HIV infection.20 (Note: Do not hold off PrEP and HIV testing until the patient has achieved a period of sexual abstinence.)
- A patient starting PrEP should have normal renal function and should not be taking contraindicated medications, such as long-term high-dose nonsteroidal anti-inflammatory agents.
- Hepatitis B virus (HBV) surface antigen, surface antibody, and core antibody should be tested because both emtricitabine and tenofovir are active against HBV. For a patient who has active HBV infection, particularly with cirrhosis, there is a theoretical concern that starting and stopping PrEP can lead to flares of HBV infection. Patients who are not HBV-immune should be vaccinated.
- Baseline hepatitis C virus testing is recommended for patients who inject drugs, MSM, or those who were born between 1945 and 1965; annual hepatitis C virus testing is recommended for patients who inject drugs.15
When it has been determined that a patient is eligible for PrEP, a prescription is written for no longer than 90 days to ensure regular monitoring for HIV infection, STIs, and renal function.
Adherence counseling is a key component of PrEP delivery—as it is with oral contraception, antihypertensive medical therapy, and other medications. As noted, HIV acquisition in PrEP users is most often reported in patients with poor adherence,8 especially among adolescents.21 PrEP is part of comprehensive sexual health care, and safer sex behaviors, such as condom use, should be encouraged to reduce the risk of acquiring other STIs. Condom use should not, however, be a requirement for continuing to receive PrEP.
Is PrEP safe?
Although PrEP might be new to many family physicians and their patients, trials and observational studies have repeatedly shown that for people without HIV infection, taking daily emtricitabine and tenofovir for prevention of HIV infection is safe. No clinically significant renal, bone, or other toxicity has been reported, although there is concern about potential toxicity after decades of use.22,23 A recent narrative review from the David Geffen School of Medicine at the University of California Los Angeles compared safety findings from 5 major studies on PrEP with 2 major studies on aspirin safety and found that PrEP is as safe as aspirin, although the authors cautioned that more study on long-term use is needed.24
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