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 Ben, being a little bit late on the last dose is nothing to worry about. It will still be effective.
Iam on PrEP on demand
8pm monday
8pm tuesday
9:30 wednesday
Wondering if taking the last pill 1h30mins late is something to worry?
Hi Nick, it is good to that you used condoms. This means that there is no risk to you. It is difficult to say the level of protection your PrEP had. Some PrEP is better than no PrEP but as it was not taken as suggested for event-based I don’t know how much protection would have been offered. As you took a dose before sex, even though this wasn’t double, you would still have some protection. It is also possible that some medication from Saturday was still in your body on the Monday which would further help.
Hello. While on holiday, things became quite hectic and this is what happened:
1. Took double dose on Saturday afternoon, two hours before I had planned sex, but then didn’t have sex.
2. On Sunday had no sex, and forgot to take one dose in the afternoon.
3. On Monday morning, I remembered I missed a dose, so took one pill. I then had sex during the day. Took another dose in the evening.
4. On Tuesday, I forgot to take the evening dose.
5. On Wednesday, I took a dose in the evening after having remembered I had forgotten.
6. Now continuing to take evening doses.
What would my protection be? I am not overly concerned, as when I was fucked we used condoms, but I thought I’d ask.
I also have understood event-based prep is not for me.
Hi Asher, yes your PrEP will still work properly. Being a few hours late on the third day is not going to cause a problem. As you had doses before and after this, there is no risk of PrEP failing for this reason.
So I did on demand prep. Did not have sex the 1st night as expected but continued. This is the timeline:
Thursday: between 4 and 6pm took 2 pills
Friday: took pill at 4.
Had sex at 2 am
Saturday:was late but took pill at 630pm
Sunday: took pill at 4pm.
My question is did it work properly
Hi John, while being late with the last dose is not ideal, this is still very likely to work. This is because the first 3 pills in your system will still be active.
The higher initial dose allows for some leeway in being late with the following 2 doses. There is no reason to worry.
Hi, I take prep on demand.
Sat 2 pills (13:00) had sex at 2am
Sun 1 pill (13:00)
Mon 1pill (18:00)
Wondering if taking the last pill 5h late is something to worry?
Thanks for your help
Hi Mr Jones, while your dosing was a few hours outside of recommended dosing. There would still be enough PrEP in your body to be effective.
Hi, im taking PrEP on-demand.
Monday 3am i took the first 2 pill.
Tuesday 4am (1 pill).
Wednesday, i missed my schedule, had sex 6am and took 11am (1 pill).
Thursday 4am (1pill)