Question
Will taking PrEP late work with on demand dosing?
27 April 2020. Related: All topics, PrEP.
Hi, I take PrEP with on demand dosing and after having sex after my first double dose i remembered my first dose post sex on time. However, my second dose was 5h late and 3rd dose was 5h late too. Will this affect my level of protection and should i continue taking it 5h late every day?
Answer
Hi
Thanks for your question. The easy answer is that you will probably be fine.
Both the drugs in PrEP stay in your body to allow for a few hours being late with dosing.
It is better to try to take them at the right time.
The after sex doses with on demand dosing only need to be taken 24 hours and 48 hours after the first double dose. Taking an extra dose for a third day will not do any harm though.
If you are still having sex every day though, then continue taking PrEP until 24 and 48 hours after the last time you had sex.
More information on real life examples for on demand dosing.
Hi Ian, you are covered by event-based dosing, see:
https://i-base.info/guides/prep/real-life-examples-for-on-demand-dosing
You didn’t need to take two pills on Monday, but this will still be okay. For the future, you only need single pills after the first double-pill start dose. You can carry on taking daily pills for as long as you need protection, for example if you keep having sex,
Hi, I am on on-demand PrEP dosing and took 2 pills on Sunday at 00:30am. I did not have sex on that day. I took another 2 pills on Monday at 8pm, however I had sex an hour after taking the dose, at 9pm. I had sex with two guys, it was anal sex, no condoms were used, one of them came inside of me. I do not know their HIV status. Today, on Tuesday, I took one pill at 8pm and I am planning to take another one tomorrow (Wed) at 8pm. Is this enough protection?
It’s been 24h since the encounter, so I still have time to get on PEP just in case! Your answer would be appreciated!
Hi Adam, PrEP can be effective if taken at least 4 times a week. Less than this and the effectiveness of PrEP will be limited.
Is your boyfriend on treatment/has a suppressed viral load? If it is below 200 there will be no risk of transmission and you would not require PrEP. This is called U=U: https://i-base.info/u-equals-u/
Being on some PrEP with the same partner means that this is a low risk exposure. Even if you have not taken enough PrEP, it is very unlikely that PEP would be recommended in this case – you do not need to be worried about this exposure.
Hi. I’ve been on prep for at least two years now but in the past month, I haven’t been consistent with it due to my boyfriend and I using protection all the time. Instead of taking it everyday, i’d take it maybe 3 or 4 times a week. We recently had sex (saturday) and we didn’t use protection and prior to that, the last time I took my prep was on Thursday. I took my prep on Sunday morning and again this morning and i plan on taking it everyday from now. Would there be much to be worried about?
Hi Mark, as your partner had used a condom there is no risk of transmission.
Please see here for more information: https://i-base.info/qa/factsheets/hiv-transmission-and-testing
I had sex with condom but my partner ejaculated inside with the condom on. But I am worried that there might be some spillage, but the condom is intact and his penis is still fully erect when it was withdrawn. I was so worried that I might get infected so after two hours (2AM) I decided to take two starter dose of prep, and now I’m on my second dose and planning to take it 12AM. Would that be ok? Thank you
Hi Mark, no you do not sound silly.
Yes you are correct. You can continue with daily dosing now until 2 days after the last time you have sex. It is safe to move from on-demand dosing to daily in the way that you have mentioned.
Sorry to sound silly, i have been on demand dosing however this instance i took my first 2 on Tuesday 7pm then had sex around 3hours later, then took one Wednesday at 7pm and again today at 7pm, i do have plans to have sex again over the weekend so do i continue to just daily dose untill 2 days post sex if no further plans for sex arise?
Hi Maximillian, yes this will be enough protection. Your first course was completed. There will have still been enough PrEP in your body to account for being only half an hour early with the second course. You do not need to worry.
Hey there!
I’m on event based-prep. I took 2 initial doses of prep at 2am Friday, and had unprotected sex at 2pm Friday, then took 1 at 2am Saturday, and took 1 at 2am Sunday. Then, I thought I was not going to have sex so stopped the medication. However, I had unprotected sex at 7pm Monday and took 2 initial pills only half an hour before. Then had 1 pill after 24 hours and 1 pill after 48 hours. I was wondering whether this will offer enough protection? Should I be worried?