Question
What is the evidence for i-Base info about stopping PrEP?
26 August 2024. Related: All topics, PrEP, Stopping treatment.
In terms of stopping PrEP, i-Base advises to wait 7 days with daily dosing after your last sexual encounter.
However, most sites recommend 28 days after the last sexual encounter (same as taking PEP).
Is there any particular research that the 7-day suggestion is based upon? Thanks very much.
Answer
Hi
Thanks for your question – it is always good to go further to look at the evidence and then in details at those studies.
I think your question refers to information in the i-Base UK guide to PrEP. [1]
In this case, the recommendation is based on the UK (BHIVA/BASHH) guidelines. [2]
The evidence to support the safety of stopping after seven days varied depending on how PrEP was being used.
If this was for anal sex, then the IPERGAY study in gay men proved this was safe because it was testing on-demand dosing that ended 48 hours after the risk. As there were no infections with this dosing, daily dosing for seven days is also proved to be safe. [3]
The protection during vaginal sex is different because PrEP meds are absorbed less well in these tissues, and drop more quickly after dosing.
Two studies were reference for the conclusion that seven days would be enough though when daily dosing was being used by women and trans people for vaginal protection. [4. 5]
Hyperlinks to these references are also included below.
As a comment, many aspect of PrEP, including dosing, have come from interpreting results from different studies. For example, there is no direct evidence for the target levels of PrEP drugs, or the thresholds for efficacy, or even in what types of tissue or cells these levels should be measured.
We do know PrEP is close to 100% effective though when taken as prescribed.
- Some guidelines might have been over cautious in their initial decision to recommend 28 days.
- Similarly, some guidelines took many years to recommend on-demand dosing.
- The February edition of the i-Base PrEP guide includes additional studies that are not currently included in any PrEP guidelines. These studies show that PrEP dosing is not affected by sex or gender.
References
- i-Base. How to stop PrEP safely. UK guide to PrEP.
https://i-base.info/guides/prep/can-i-stop-prep-completely - BHIVA/BASHH guidelines on the use of HIV pre-exposure prophylaxis (PrEP), 2018
https://www.bhiva.org/PrEP-guidelines - Molina JM, Capitant C, Spire B et al. On-demand preexposure prophylaxis in men at high risk for HIV-1 infection. N Engl J Med 2015; 373: 2237–2246.
https://www.nejm.org/doi/full/10.1056/NEJMoa1506273 - Seifert SM, Glidden DV, Meditz AL et al. Dose response for starting and stopping HIV preexposure prophylaxis for men who have sex with men. Clin Infect Dis 2015; 60: 804–810.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4402345 - Cottrell ML, Yang KH, Prince HM et al. A translational pharmacology approach to predicting outcomes of preexposure prophylaxis against hiv in men and women using tenofovir disoproxil fumarate with or without emtricitabine. J Infect Dis 2016; 214: 55–64.
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4907409
This answer was updated in August 2024 from a question first posted in September 2018.
Hello Peter and thanks for the question.
No unfortunately this is not true.
To have enough PrEP in your system to protect you you need to follow the dosing schedule described here:
https://i-base.info/guides/prep/real-life-examples-for-on-demand-dosing
Please also read the guide to get better informed about PrEP:
https://i-base.info/guides/prep
Hello. Is it true that protection lasts up to one week after stopping PrEP? I mean, let’s suppose you take PrEP daily but decide to stop. Would there still be enough PrEP in your system to offer strong protection in a risk encounter (over 90%) for up to a week?
Hi Ravi, thanks, please learn about HIV here, especially the FAQ link.
https://i-base.info/qa/11844
This service is not about HIV risk and testing because all this info is online at the link.
Hi Simon. I also have one more question regarding potential exposure. So before 8 weeks, I had sex with a Sex Worker with Condom (Also condom stayed intact didn’t split or tear), kissed on her lips with Mouth closed for five to six times & She gave me blowjob without condom for 3 mins. But before starting Prep my doctor tested me for 4th Gen HIV 1&2 Antigen antibody test, which was non reactive after 52 days. So is this conclusive? Asking his before today I am having mild cold.
I started taking Prep because of above stress
Also after taking Prep (Truvada) for a day after dinner, the next morning my temperature weng slight up to 99.1 from my normal 98.3 & Feeling Tired & feeling like I have no energy in my body. Did not able to eat properly. So is this normal? Due to this I stopped talking it because it would affect my workload.
What I need to do to avoid the above tiredness feeling because if this stays, I won’t be able to enjoy the Sex. Please help.
Hi Ravi, neither the type of HIV or your country have any impact on how PrEP is taken. The information on the i-Base website is based on evidence from good research that is also used in guidelines.
https://i-base.info/uk-guide-to-prep-february-2024/
Thank you Simon for the prompt response. My doctor says to take it for 7 days before encounter. 14 days after encounter to get maximum safety. So what shall I do? Is this dosage because I am in India? the Virus type is different here than the Western Countries?
Hi Julian, please see this guide which has the most up-to-date info on PrEP:
https://i-base.info/uk-guide-to-prep-february-2024/
This section has info on starting and stopping PrEP, which can be different depending on circumstances.
https://i-base.info/guides/prep/how-to-take-prep
Protection depends on continuing to take daily PrEP after sex, for either 2 or 7 days.
After taking PrEP daily for over two months, how many days or weeks can I consider it to still offer protection following a potential risk of exposure? I’ve read on some sites that it provides protection for over a week, though the effectiveness decreases each day until 70% after one week. However, other sources say that after stopping the medication, protection ends immediately, and I should consider myself at risk after 24 hours, as if I had never taken it. Can you clear this, please?
Hi Ravi, please see this link to up-to-date info on PrEP dosing:
https://i-base.info/uk-guide-to-prep-february-2024/
This includes that everyone can start PrEP with a double dose (2 pills) and be protected within two hours. No-one needs to take PrEP daily for seven days to get protection now.
Hi,
So it is ok fo stop PrEP after 7 days (one pill in 24 hours) of last exposure? I am planning to take PrEP 7 days before exposure. Please guide.