Specific question about missed doses

[BellyAndBriefs]

So, if I was prescribed prep and then did not take it over a long weekend due to forgetting it at home (no doses Saturday, Sunday, or Monday), only to return on Tuesday and take a dose later in the day, and I wanted to cruise today, on Wednesday for some loads within an hour after I take my next descovy pill, am I at a considerable risk for developing a possible med resistant hiv infection, presuming at least one of the tops at the cruising spot is positive and detectable? I know everyone will say err on the side of caution, but I was curious if anyone knew what my odds were, going from taking it every single day, to 3 days off, then 2 days on.

[viking8x6]

Short answer: No, you're not (depending, of course, on what you mean by "considerable risk"). Nobody knows exactly how much risk, because nobody has ever done a controlled study on that particular usage pattern (which should be no surprise). But (1) the presumption you specify (at least one detectable top) is moderately unlikely, because the rate of detectable poz tops is relatively low these days, and (2) even if you did cross paths with a detectable top, your chances of seroconverting by taking a load from him are only (roughly) 1 in 70.

Longer answer: Your body levels of medication will be somewhat lower than they would be at steady-state (if you had been taking one pill a day regularly for at least a week). Not a lot lower - although pharmacokinetics vary between individuals, it takes the body significant time to clear the drugs from your system, plus you already re-started. So your chances will be substantially lower than they would be without it.

What I would do: Given what I know about drugs, antibiotics, and pharmacology, in your shoes I'd take an extra pill today and then continue with one per day. That would be exactly the same (over the next 3 days) as the standard 2-1-1 "on-demand" PrEP protocol, which has been validated to be effective (though admittedly not with Descovy, but there are good chemical reasons to believe that it will behave comparably).

 

[BellyAndBriefs]

23 hours ago, viking8x6 said:

What I would do: Given what I know about drugs, antibiotics, and pharmacology, in your shoes I'd take an extra pill today and then continue with one per day. That would be exactly the same (over the next 3 days) as the standard 2-1-1 "on-demand" PrEP protocol, which has been validated to be effective (though admittedly not with Descovy, but there are good chemical reasons to believe that it will behave comparably).

 

So, thanks for responding yesterday. I have another slightly silly follow up. I took 1 pill about an hour and a half before cruising and took another one when I got there, took two loads within the hour following probably. That being said, I went back to taking it at my normal time today so the time line goes as follows: no missed doses for months, then missed Saturday - Monday, then taken once on Tuesday, twice on Wednesday, and once more on Thursday. That being said, how long would you recommend I wait until I do hook up with a detectable top. I know someone who is poz and off meds (he says it's only been a short time but I am not sure if I trust that). I've seen him around on sniffies being a total cum dump lately and I wanted his (likely toxic) load. Presuming he is HVL now, should I wait a full week of being back on descovy before I let him cum inside me or do you think I'd be fine now presuming I continue my regimen of once daily. 

[viking8x6]

You'd probably be fine now.

The tenofovir component of Descovy has a very long half-life in the body (150 to 180 hours), so even after three days missed you'd have had pretty significant levels active in your peripheral white blood cells (where it does its work). Three doses in, you'd have built that most of the way back up to the steady state level.

But ideally, you should wait. You knew that.

[Poz50something]

viking8x6 said:

The tenofovir component of Descovy has a very long half-life in the body (150 to 180 hours), so even after three days missed you'd have had pretty significant levels active in your peripheral white blood cells (where it does its work). Three doses in, you'd have built that most of the way back up to the steady state level.

But ideally, you should wait. You knew that.

 

 

In the 2010s, I took part in a study as my doc is a world specialist in HIV and Hep C. I went off meds for 4 months, while the study team subcutaneously injected me with my own cd8 cells which were made super viral fighting through a secret process. I was one of the longest lasting test subjects. Some of them lasted a week or two before viral loads went dangerously high. I suspect there was a commercial component to the study.  I stopped in 2010 because I and late hubby were going to visit my parents for their 50th anniversary, and didn't want the hassle of going through the med system of a country whose citizenship I had given up.  I know it's dependent on each person, and Descovy is not used to treat HIV,  but 4 months without meds and I was mostly tired, headachy, and grumpy. Not sure that helped, but that's my 2 cents.      

[ErosWired]

To add to the responses above, you specifically asked whether you would be at higher risk for a meds-resistant HIV infection. The meds-resistance of a strain you might become infected with is not a result of your level of medication barrier at the time of infection, it’s a mutant characteristic of that particular strain that has development in some other host. These are called “breakthrough infections”. Your chance of encountering such a strain is entirely random, and your chance of becoming infected with it will depend on its level of resistance to the medication used for prevention.

If your adherence to your PrEP regimen is suboptimal (careless, neglectful, lackadaisical, not taken as directed) it is possible to acquire a common-or-garden strain that then becomes meds-resitant within you because PrEP is not the same as ART and the drugs in PrEP do not fully suppress the virus. In such a case it’s difficult then to know whether the mutated resistant strain came from outside or was home-grown.

Are we terrified yet? Historically in the Americas, med-resistance at some degree has been found in 10% of cases presenting for treatment. The efficacy of first-line NNRTI-based meds at viral load suppression has averaged about 81% for those receiving first-line ART, 70% for those receiving second-line ART. That was before Dolutegravir-based treatments, which are showing significantly higher effectiveness in suppressing viral load. Nonetheless, the take-home from this is that if you don’t want to take it home, stick to your PrEP.

I know you want to cruise, but the world won’t end if you decide to skip it for a couple of days while your level of protection builds back up.

Source for above info: WHO

[think before following links] https://www.who.int/news-room/fact-sheets/detail/hiv-drug-resistance#:~:text=Pretreatment HIV drug resistance,-Drug resistance can&text=Up to 10% of adults,previous exposure to antiretroviral drugs.

Edited September 22, 2023 by ErosWired