[Question #7746] PEP effectiveness

 
15 days ago
How effective is PEP (Truvada & Isentress) if only taken for 10, 14 or 21 days? It was started within 24 hours of potential exposure. Years ago, I was prescribed Truvada and Prezista. Due to elevated liver and stomach issues it was discontinued after 17 days. Hopefully, Isentress will be better tolerated and I can complete 28 days. If not, I am curious as to effectiveness at a lesser number of days. Thank you.
Edward W. Hook M.D.
Edward W. Hook M.D.
15 days ago
Welcome to our Forum and thanks for  your question.  you ask a good question.  Unfortunately, there are not good answers. The studies which evaluated PEP for HIV prevention were designed to evaluate 30 days of therapy and available data on shorter courses are limited.  We now know that more people who acquire HIV have virus detectable in their blood within 10-12 days of exposure so it is logical that the majority of PEP effect also occurs during that period but as far as being a scientific fact or proven, we just don't know.  We also do know that the earlier PEP is started after an exposure, the more effective it is so that you began treatment about 24 hours after exposure is a good thing.  

From the sound of things you have begun PEP now, a  2nd time.  You do not describe your exposure so I cannot comment on risk but if you have required PEP on multiple occasions, you may want to consider PrEP rather than PEP.  In general, the medications used for PrEP are better tolerated that those given for PEP.  EWH
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14 days ago
Dr. Hook,
In hindsight first course was unnecessary as it involved cut on finger. I had not found your forum then. Recently, I was involved with stranger for brief anal sex encounter. A condom was put on and penetration was minimal if any. We stopped and I noticed condom was not on. I cannot say if unprotected dipping occurred or not. I had been drinking. As abundance of caution I decided to go on PEP. If I see any ill effects from PEP I will likely discontinue. Let me know if you have any thoughts. Also, how is Isentress generally tolerated compared to Prezista?

Thank for your prompt reply and valuable service provided on this web site.
Edward W. Hook M.D.
Edward W. Hook M.D.
14 days ago
Thank you for the additional information on your encounter. I agree that in this situation Papp may be warranted. In general the newer antiretrovirals are better tolerated than earlier drugs.

Please feel free to let me know if there are further questions. EWH
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