Not Taking PrEP Correctly?


A friend of mine did not follow guidelines before having unprotected sex. He took two tablets 30 hours before sex and then again 1 hour before having sex. what are the risk of catching HIv. What treatment should he follow. He has taken one more tablet 12 hours after.


HI there - Your friend is fortunate to have you looking out for him. The approved regimen for taking PrEP varies a bit by geographical regions. In the United States, daily use is the recommended protocol by the CDC. (

However, in other parts of the world, the intermittent dosage strategy tested in the "Ipergay" trial is often recommended. This is a regimen that involves taking 2 doses of Truvada anywhere from 2 to 24 hours prior to any potential HIV exposure, than 1 dose 24 hours later, and another dose 48 hours later, and then daily if potential exposures are ongoing. (

In the case of your friend, it sounds like he is loosely following the Ipergay protocol, but not exactly. It is quite possible that 2 tablets 30 hours before sex, and then one hour before sex may protect, but that wasn't measured in these trials. Also, taking only one dose following a potential exposure may provide protection, but whether or not it is sufficient enough wasn't studied.

I'd highly encourage your friend to sit down with his provider and figure out a proven workable plan to take PrEP that will maximize his protection. What he is doing now is not a proven strategy, and could result in acquiring HIV if exposed to a detectable viral load. If either you, or him, want to learn more about PrEP and dosing regimens, feel free to check out the international Facebook group page at "PrEP Facts: Rethinking HIV Prevention and Sex" (