This July, the Food and Drug Administration approved a pre-exposure prophylaxis (PrEP) to help keep folks HIV negative. PrEP involves taking a daily dose of HIV meds—in this case, Truvada—to lower the risk of contracting the virus. The approval was met with both optimism and caution.

Truvada is a combination pill of two drugs (tenofovir and emtricitabine) commonly used for HIV treatment. “When taken as PrEP, Truvada can block HIV replication from occurring and prevent HIV from establishing infection in the body,” explains Albert Liu, MD, MPH, the director of prevention interventions at the San Francisco Department of Public Health.

The other good news about PrEP is that Truvada boasts few side effects beyond the annoying gastro-intestinal discomfort some people experience. And even then, “there are things people can do to reduce these symptoms, such as taking the medication with food at night before going to bed,” Liu says.
But here’s the biggest problem: For best results, people must take the pill each and every day. That’s because the meds must build up in your system in order to work, and researchers aren’t sure how many doses you can miss and still have protection.

Still, if life happens and you miss a dose, get back on track by taking a pill a day. But, Liu warns, “If you miss doses frequently, it can be helpful to talk with your clinician who can discuss strategies to help with pill taking.”

But docs have other concerns about Truvada as PrEP. One is how the drug will affect people’s kidneys and bone density long-term. Another is the possibility that people who skip doses might contract HIV that is resistant to the meds. And then there’s the worry that folks might engage in risky behaviors because they’ve popped a pill and think they’re protected. (PrEP is supposed to be used in addition to condoms, not as a substitute for them.)

On the consumer side, advocates point out that the $1,200 per month price tag makes it out of reach for many at risk—especially those without health insurance benefits.

Still, many doctors feel PrEP is a great option for people who have ongoing potential HIV risk. Specifically, it might be appropriate for men who have sex with men, transgender women and HIV-negative heterosexuals who have positive partners not yet on a drug treatment regimen.