I am in a long term relationship in which there was a "break" over a year ago, on this break my partner was infected with hiv. We are still together and he has been on antiretroviral therapy for over a year and is considered undetectable. I have not been to the doctor with him in quite some time as he has become more comfortable going alone, so I am unsure of his viral load and am not there to ask. I am aware that he sometimes misses doses of his medication but doesn't miss more than one or two. We once had unprotected sex while under the influence and I was prescribed PEP (generic combovir) and was given refills and have had it refilled. I have been taking it continuously without side effects and have educated myself to the point of understanding that I need a PreP instead of a PEP. I am concerned that the pep won't work given we had sex two days ago where I was the insertive partner, unprotected. Does combovir prevent hiv in the same way truvada might? I'm a little worried and just need a little peace of mind. Thankyou for your feedback in advance.


Hello and thank you for your thoughtful and interesting question.

Truvada PrEP is very highly effective (if taken with reasonable adherence) in preventing HIV infection and there's strong clinical trials and epidemiological evidence for it's use, especially among men who have sex with men.

There's no data on the use of Combivir for PrEP (but there is support of it's use in PEP). Having said that, it's entirely plausible that Combivir would have PrEP activity. The main reason why it's not being explored for PrEP is that the AZT part of Combivir forces twice-daily dosing and is usually not as well tolerated as the medications found in Truvada. Fortunately, since you are tolerating your Combivir, this isn't as much of an issue. Just make sure that your adherence is as close to 90% or greater.

As for your particular risks, if mutually monogamous and your partner has an undetectable viral load, your HIV risk is very low. Absent confidence in these important data, PrEP is something worthy of considering, just as we consider for all sexually active gay men in our APEX Family Medicine clinic in Denver.

I hope that's helpful, BY