Fast Five Quiz: How Much Do You Know About HIV Pre- and Postexposure Prophylaxis?

Jason F. Okulicz, MD


July 15, 2019

Although all the drugs listed are used to treat HIV-1, FTC/TDF is the only medication approved by the US Food and Drug Administration for HIV PrEP. FTC/TDF for PrEP is indicated in combination with safer sexual practices to reduce the risk for sexually acquired HIV-1 in adolescents and adults at high risk for infection. In addition to having a long half-life and high barrier to genetic resistance, FTC/TDF has been shown to achieve high concentrations in genital secretions and macrophages. Moreover, clinical trials have shown FTC/TDF to be safe and well-tolerated in patients.

One concern some researchers and clinicians have regarding the use of PrEP is the potential for drug resistance. Cases of drug resistance have been reported in patients who failed PrEP and were subsequently diagnosed with HIV infection. However, this has mostly been observed in patients whose HIV-positive status was unknown at the time of PrEP initiation or in patients who were nonadherent to PrEP. Because nonadherence is strongly correlated with PrEP failure, it is important that clinicians communicate and reinforce the importance of adherence.

In addition to concerns over resistance, data are also being collected on women who become pregnant while receiving PrEP agents, as risks to the fetus have not been studied. To date, data collected from the antiretroviral pregnancy registry, as well as data from observational studies, demonstrate no increased rate of major birth defects in infants whose mothers took FTC/TDF during pregnancy.

Before prescribing PrEP, clinicians should counsel patients on safer sex practices to further reduce the risk for sexually transmitted infections (STIs). Despite concerns that PrEP encourages high-risk behavior, this has not been demonstrated in clinical trials, and data from observational studies have varied.

For more on FTC/TDF for PrEP, read here.


Comments on Medscape are moderated and should be professional in tone and on topic. You must declare any conflicts of interest related to your comments and responses. Please see our Commenting Guide for further information. We reserve the right to remove posts at our sole discretion.
Post as: