Starting PREP

[Guest PlanetJunk]

How long should I wait before having bareback sex? Is there a initial period where I should take it for a few days before to get it in my system? Or after I take that first pill go have some Anonymous bareback sex and you're fine after a few hours of taking it?

 

[BootmanLA]

It's not immediate. It's not as though the moment you have any PrEP components in your bloodstream at all, you're safe from infection.

Some studies suggest that if you take PrEP every day, it reaches its maximum protection in blood at 20 days, in rectal tissue at about 7 days, and in vaginal tissues at about 20 days. Meaning: at least a week before you get fucked bareback. 

Think of it this way: If you take a single pill, it will take several days for it to completely leave your system. But it starts leaving shortly after you take it (as your body begins to distribute and then also filter it out). Let's say for the sake of argument that over the 24 hours following a dose, 20% of it has been filtered out of your system. So after 24 hours, you only have 80% of a dose in your system. Take another dose, and a day later you have 60% of the first dose and 80% of the second dose. Take another dose, and in 24 hours you have 40% of the first, 60% of the second, and 80% of the third. I made up those percentages, and it may not be a steady decline, but the point is that it takes time for any particular dose to get filtered out of your system and if you keep taking it, your system eventually hits a plateau where it's keeping your system at a "working" level.

Because it's easier to contract HIV through contaminated blood or vaginal sex than through anal sex, it takes longer for therapeutic levels to be attained in blood and in vaginal tissues. 

[Guest PlanetJunk]

9 minutes ago, BootmanLA said:

It's not immediate. It's not as though the moment you have any PrEP components in your bloodstream at all, you're safe from infection.

Some studies suggest that if you take PrEP every day, it reaches its maximum protection in blood at 20 days, in rectal tissue at about 7 days, and in vaginal tissues at about 20 days. Meaning: at least a week before you get fucked bareback. 

Think of it this way: If you take a single pill, it will take several days for it to completely leave your system. But it starts leaving shortly after you take it (as your body begins to distribute and then also filter it out). Let's say for the sake of argument that over the 24 hours following a dose, 20% of it has been filtered out of your system. So after 24 hours, you only have 80% of a dose in your system. Take another dose, and a day later you have 60% of the first dose and 80% of the second dose. Take another dose, and in 24 hours you have 40% of the first, 60% of the second, and 80% of the third. I made up those percentages, and it may not be a steady decline, but the point is that it takes time for any particular dose to get filtered out of your system and if you keep taking it, your system eventually hits a plateau where it's keeping your system at a "working" level.

Because it's easier to contract HIV through contaminated blood or vaginal sex than through anal sex, it takes longer for therapeutic levels to be attained in blood and in vaginal tissues. 

Thank you for the reply! 

[BBSMKR]

In Scotland the guidance for taking PrEP on demand is to take 2 (double dose) between 2 and 24hrs before sex, then continue taking a single dose daily for 48hrs beyond sex. Of course the guidance in your country my differ.

[tallslenderguy]

Here's one journal article dosing recommendation:

"Daily, continuing, oral dose of coformulated tenofovir and emtricitabine ≤90-day supply 
Patients need to take a daily dose of PrEP for 7 days before high levels of protection are achieved for both vaginal and rectal exposure to HIV"

[think before following links] https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5518248/

[dacoman]

The most universal advice I heard is that you take prep for a week before bb. In reality, three days would already give you some immunity. I also heard there's something called on demand which you take several pills before and after as it is "on demand".

 

Personally I would say wait for a week and take the pill daily. In this way, you will basically be immune and do not have to worry about HIV at all.

[BootmanLA]

4 hours ago, dacoman said:

The most universal advice I heard is that you take prep for a week before bb. In reality, three days would already give you some immunity. I also heard there's something called on demand which you take several pills before and after as it is "on demand".

 

Personally I would say wait for a week and take the pill daily. In this way, you will basically be immune and do not have to worry about HIV at all.

Correct. The "on demand" method, which is considered "off-label" and not officially sanctioned by most health authorities, might seem appealing because hey, doesn't it mean you take fewer pills?

Not necessarily, actually. The downside to "on demand" is that it basically needs to be taken *every* time you have sex, and you have to take the initial, "double" dose at least 2, and no more than 24, hours before having sex, followed by a repeat dose 24 hours after the first, and another 24 hours after the second.

So let's say you typically have sex three times a week - on Wednesday (Hump Day), Friday and Saturday. That means you take 2 pills during the day Wednesday, plus a second  on Thursday and a third on Friday.

But hey - you're gonna have sex again on Friday, so your Friday dose has to be double, plus you'll need one each on Saturday and Sunday.

Oh wait, you're going to have sex again on Saturday. So that means Saturday's does needs to be double, too.  You're already taking one on Sunday, but since it's doing "double duty" as clean up for both Friday and Saturday's sex, you might need that one to be doubled as well, plus one on Monday to finish out the post-Saturday sex. But no pill on Tuesday needed.

But 2 on Wednesday, 1 on Thursday, 2 on Friday, 2 on Saturday, 2 on Sunday, and 1 on Monday, puts you at ten pills for 7 days. If you'd started a week early, one pill a day would put you in the routine, less likely to forget what your dose today needs to be, and less medication overall. 

Now if you only have sex once every week, or every other week, yeah, on-demand may make sense. But for anyone with any sort of steady sex life, daily is the way to go.

[Guest]

On 11/12/2020 at 7:09 AM, PlanetJunk said:

How long should I wait before having bareback sex? Is there a initial period where I should take it for a few days before to get it in my system? Or after I take that first pill go have some Anonymous bareback sex and you're fine after a few hours of taking it?

 

 

On top of the advice you received here so far, your doctor will explain you in detail every step of the procedure and might even have a printed pamphlet. Don't be afraid to ask questions as they're there to help.

The daily vs on-demand 2-1-1 has been debated quite a lot here already, you might ask your doctor about this too but I'm inclined to believe he/she'll recommend taking prep according to your sexual habits (hence the need to be completely honest) and your own country's guidelines.