I had a potential exposure with a woman during vaginal, but I hopped on pep around 35-36 hours later. I would like to know how effective my pep is going to be and how risky my encounter was. At the clinic I tested negative of course. The PEP I was prescribed was 50 mg tivicay and emtricitabine/tenor 200 300 mg tabs to take at the same time every 24 hours. I’m really worried that I might’ve contracted it and just want to know how well PEP will work and if you’ve even seen anyone take PEP properly and test positive. Again I took the medication no later than 36 hours from exposure but the earliest I took it might be 34 hours but I highly doubt it. I know it says up to 72 hours but online it shows the efficacy drops after some time.

Welcome back to the Forum.  You don't say anything about your partner but I suspect she was not particularly likely to have HIV (having had prior partners does not count, even lots of partners).  As I said to your 3 moths ago - "Far fewer than 1% of women in the U.S. have HIV and even if she did, the risk for infection following a single vaginal exposure (there is no known risk from receipt of oral sex from an untreated HIV infected person) leads to infection in fewer than 1 person in more than 1000 exposures."  Thus, your statistical risk for HIV is less than i ni 100,000 and likely far lower.  If you had come to my clinic requesting PEP, I would not have prescribed it.  That said, you are taking it now.  The medications you are taking are highly effective and reduce your already very, very low risk even more.  Precise estimates are not available becasue HIV acquisition is a rare, hard to study event but expert opinion suggests that PEP started within a day or two of an exposure and taken as directed would prevent about 80% of infections which would occur otherwise.  It also means that you cannot test for HIV with the expectation of conclusive results until at least 4-6 weeks after your last dose of PEP.---

Ok that’s great to hear I’m just concerned if I might’ve had micro tears on my penis. I looked and I didn’t see any visible cuts but I assume since it can enter micro tears I wouldn’t see what the tears look like. Also I know you just mentioned PEP is around 80% effective in cases that otherwise would’ve results in HIV, but would you say it’s 80% because of poor adherence or just the nature of the drug (like for example not taking it every 24 hours or being outside of the 72 hour period.) I took it at no later than 36 hours but I feel like I definitely should’ve started earlier for some reason 36 hours still seems late for me. Finally have you or any colleagues personally seen anyone take PEP and end up with HIV after all is done? 

"Microtears" sound like something you heard on the internet and are irrelevant.  If you didn't see abrasions, you're OK.  Remember, sex is all about friction.---

I hope you’re right. I just have an overwhelming anxiety that the PEP might fail if I am infected is all.