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 Leiter, thanks, great you are doing so well on PrEP. This time difference will not have made any difference – please don’t worry. Anyone taking daily PrEP will keep good drug levels so long as you are taking four or more doses a week. PrEP is very flexible for the actual times in this situation.
Hello there,
I have been taking daily PrEP since the 2nd of January this year at around 7:00pm to 7:30pm. I have not missed a dose. However, yesterday I didn’t take the pill until 10pm as I didn’t have my phone or watch to remind me. Will taking the pill 3 hours late reduce the efficacy? The day before, I had unprotected receptive and insertive oral sex with men. The last time I had unprotected insertive anal sex was on the 7th of March.
Hello Jay and thanks for getting in touch.
It should be ok, keeping in mind you took all the required doses within a timeframe described in research.
However, the information we have from research doesn’t exactly cover your circumstances.
It’s always best to take PrEP than not, though.
Hi
So I’ve go a pea brain and even the alarm reminding me didn’t help me
So I’ve taken
2x dose – Saturday 5pm
Unprotected sex 7:30pm
Single dose – Sunday 4:50pm
Missed my dose Monday until 2am Tuesday early and taken 2x just in case
So missed it by 8/9hrs
Will this be ok? the guy also in prep so….
Hello Jay and thanks for getting in touch.
PrEP does work if taken 2 hours before sex (even better if you took it 3 hours before).
Please see here for more information (take a look at the information on dosing, I feel there are things you misunderstood):
https://i-base.info/guides/prep
Hi, I am a man who had unprotected sex with a woman. I took PrEP 2-1-1, starting 3hours before the sex – however I read that for insertive sex, on-demand PrEP may not work as intended – it may require more time to reach and protect the pe*is? Am I in danger?
Hi Sam, please see the info on dosing here – you don’t need to be exact on the timing:
https://i-base.info/uk-guide-to-prep/
Hi,
I am taking on demand prep and my event as below;
Friday – 8.30pm – I took double dose
Saturday – 6.00pm – unprotected sex
Saturday – 8.45pm – single dose (15 minutes late)
Sunday – 10.45pm – single dose (2 hours late)
Monday – 8.30pm – single dose..
Since I late few hours, Am I safe and protected?
Hello Addlove and thanks for getting in touch.
Having sex includes risks, you seem to know all about it.
Well done that you are so careful and follow up with often testing and treatment as needed.
PrEP works best if taken up to 2 hours before sex.
Afte sex, you should ideally go on PEP.
If you could not get PEP on the day, well done for starting PrEP.
It’s always better to take something (ideally PEP) than nothing and well done for taking it straight away after exposure.
I feel you could benefit by taking PrEP in the future – you have the option to take it daily or on demand depending on your risk.
Please see here for more information: https://i-base.info/uk-guide-to-prep/
Hi, I have sex with sex worker. We used a condom but it broke. I started PrEP within two hours. I was diagnosed with an STI a few days later. What is my risk for HIV?