Is any preexposure prophylaxis against HIV infection available?-N.W., FLA.
Rachel Kerns, PharmD, and Dan Sheridan, MS, RPh, respond: According to the CDC, around 1.2 million Americans are living with HIV, and one out of eight of them hasn't been diagnosed.1,2 In recent years, researchers have made incredible advances in HIV prevention. For HIV-negative patients, preexposure prophylaxis (PrEP) using antiretroviral drugs is an evidence-based way to prevent new infections among those at greatest risk.3
The only FDA-approved PrEP option is an HIV medication containing two nucleoside analogue HIV-1 reverse transcriptase inhibitors, emtricitabine and tenofovir disoproxil fumarate (Truvada).4,5 Truvada is a fixed-dose combination drug for HIV-1 uninfected adults. It's indicated in combination with safer sex practices to reduce the risk of sexually acquired HIV-1 in high-risk adults. (See Who can be helped by PrEP?) If taken consistently every day, PrEP can reduce the risk of HIV by more than 90%.5,6
PrEP isn't a cure or vaccine for HIV, nor is it indicated as monotherapy for HIV-positive patients. It's intended to be only one of a multitude of prevention strategies for at-risk patients.7 Make sure patients understand that PrEP doesn't protect against other sexually transmitted infections nor does it prevent pregnancy. Teach them about other risk reduction strategies such as condom use.5,8
Also teach patients that PrEP isn't immediately protective. To achieve protection from exposure to HIV through cervicovaginal tissues requires 20 days of treatment; protection from infection through rectal tissue takes 7 days.8 Although PrEP is generally well tolerated, some common adverse reactions include weight loss, abdominal pain, and headache.4 Inform patients that these adverse reactions usually resolve within a few weeks.
The tenofovir component of Truvada can increase the risk of renal impairment and shouldn't be started in patients with a creatinine clearance of less than 60 mL per minute.9 Kidney function should be assessed 3 months after beginning therapy and every 6 months thereafter.
Educate patients to take their medication as prescribed, without skipping doses, to reduce the risk of antiretroviral therapy resistance. Also inform them that they must undergo HIV testing every 3 months to verify that PrEP is still protecting them. Because of this, the guidelines for PrEP limit the amount of Truvada that can be dispensed to a 3-month supply so HIV status and renal function can be evaluated appropriately.5
As patient advocates, nurses play an important role in identifying possible candidates for PrEP, encouraging diligent adherence to therapy, and providing patient education to help promote a safer community.
Who can be helped by PrEP?4
Appropriate candidates for PrEP include HIV-negative patients who've met any of the following criteria:
* ongoing sexual relationship with an HIV-positive partner.
* unprotected sex or recent diagnosis of a sexually transmitted infection in men who have sex with men, unless in a mutually monogamous relationship with a partner who recently tested HIV-negative.
* unprotected sex by a heterosexual man or woman with partners known to be at risk for HIV (that is, injectable drug users or bisexual male partners of unknown HIV status), unless in a mutually monogamous relationship with a partner who recently tested HIV-negative.
* injected illicit drugs, using shared injection supplies, within the past 6 months.
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