for Veterans and the Public
Frequently Asked Questions
Q: I am a heterosexual woman. For the last year I have been using PrEP to protect myself against HIV. So far it has been working great, and I like that I'm in control of it. I take PrEP every day but I heard that it still works if you only take it 4 times a week. Is that true?
We're happy to hear that PrEP (pre-exposure prophylaxis using the medication Truvada) has been a successful HIV prevention method for you. Your question is an important one. The best and most effective way to take PrEP is to take it every day, 7 days a week; this is what we always recommend. It is true that results from some recent studies suggest that taking Truvada at least 4 times a week usually produces drug levels that are high enough to prevent HIV infection. But, these data are from studies of men who have sex with men, not from studies of women. And there are reasons to be very concerned that these results will not be true for women. In women, the levels of the Truvada drugs are more variable and in some tissues they are a lot lower than in men. Thus, missing doses of Truvada may seriously lessen the anti-HIV effects of Truvada. Until we have good data from studies of alternative dosing strategies for PrEP in women, we urge to you continue to take your PrEP every day.
(And we want to remind you that although daily PrEP is very effective at preventing HIV, it will not protect you from other sexually transmitted infections or from pregnancy. We recommend you continue to use condoms regularly, and see your clinician every 3 months for STD and pregnancy tests.)