Some physicians have expressed concern that prescribing PrEP may promote high-risk sexual behavior.35 However, because PrEP is most beneficial in individuals who already engage in high-risk sexual behavior, strategic delivery of PrEP remains an effective risk-reducing strategy.17,18,21,26,36,37 Even in instances where PrEP has been associated with higher-risk sexual behavior and higher rates of sexually transmitted infections, it still prevents as much as 100% of new HIV infections.38
Fear of drug resistance also contributes to slow implementation of PrEP. Drug resistance has been observed in clinical trials of PrEP, but it has been exceedingly rare and predominantly limited to patients who had unrecognized AHI when they started PrEP.39 Furthermore, the few cases of drug resistance attributable to PrEP pale in comparison to the large number of estimated HIV infections averted—infections that would require lifelong ART with its own associated risks of drug resistance. By decreasing HIV transmission, PrEP is expected to decrease total drug resistance.40
Cost is another obstacle. Truvada costs approximately $1,540 per month.41 However, analysis has demonstrated that PrEP is cost-effective when targeted to high-risk patients.42 Most insurance plans cover PrEP, but often require high deductibles and copays; fortunately, this financial burden for patients can be mitigated or eliminated by co-pay assistance programs. The manufacturer of Truvada offers assistance programs for both insured and uninsured patients who are candidates for PrEP; details are available at http://www.truvada.com/truvada-patient-assistance.
Stigma has historically burdened individuals who seek to protect their sexual health, including HIV-negative individuals who are candidates for PrEP. Stigma surrounding HIV may decrease ART-based HIV prevention in men who have sex with men,43 while increasing high-risk behaviors44 and all-cause mortality.45
The resources listed in TABLE 2 can help physicians overcome some of the barriers to implementing PrEP.
How to deliver PrEP
Whether HIV specialists or primary care clinicians are best suited to provide PrEP is a subject of debate. HIV specialists are most familiar with ART and routine monitoring of adherence; however, they have less access to HIV-negative patients, who are the target group for PrEP.35 Family physicians tend to work in closer proximity and maintain longitudinal relationships with PrEP target groups, but in general have less experience with ART and evaluating AHI. Some may argue that competing demands may make it impractical to take a detailed sexual history during a primary care visit.46 In truth, both HIV specialists and family physicians can be appropriately equipped to provide PrEP.
TABLE 3 outlines the steps necessary to provide a patient with PrEP.47 Assessing risk is the initial step; PrEP is beneficial for patients who have one or more risk factors for HIV infection. To be eligible for TDF/FTC, a patient must be HIV-negative, and should be tested for hepatitis B virus (HBV) infection and kidney disease. Because TDF/FTC treats HBV infection, candidates for PrEP who test positive for HBV should be evaluated for treatment of HBV before initiating PrEP.Candidates for PrEP who test negative for HBV infection and immunity should be vaccinated.
Candidates for PrEP should also be screened and monitored for kidney disease. TDF can cause increased serum creatinine due to tubular toxicity. A patient who has an estimated creatinine clearance <60 mL/min should not receive TDF/FTC for PrEP. If a patient’s estimated creatinine clearance falls below 60 mL/min or serum creatinine increases by 0.3 mg/dL above baseline after PrEP is started, TDF/FTC should be discontinued, and the patient should be evaluated for the underlying cause of the kidney disease.27
Before starting PrEP, candidates should be screened for HIV infection and symptoms of AHI. Strongly consider testing for sexually transmitted infections that may increase the risk of HIV transmission, such as syphilis, gonorrhea, or chlamydia.
Strong adherence to pre-exposure prophylaxis for HIV is associated with a risk reduction of 90% to 100%.
Candidates who are eligible for PrEP must be counseled on medication adverse effects, adherence strategies, and symptoms of sexually transmitted infections. To initiate PrEP, candidates may be given a one-month supply of TDF/FTC;adherence, adverse effects, and other risk-reduction strategies are assessed at an office visit 3 to 4 weeks later. Subsequent prescriptions are then dispensed as a 3-month supply, with office visits to monitor PrEP scheduled for at least once every 3 months. During these monitoring visits, evaluate the patient’s HIV status, pregnancy status, adherence, adverse effects, risk-reduction behaviors, and indications for continued PrEP. Every 6 months, renal function and sexually transmitted infection status should be reassessed.
Reducing risk of harm among patients who inject drugs
Nonsexual transmission of HIV is a route of high infectivity.48 It includes transfusion of infected blood, sharing of equipment during injection drug use, and percutaneous needle sticks. Sharing of equipment during injection drug use is estimated to account for 8% of new infections in the United States.4
