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How Long After Stopping PrEP am I Protected?

PrEP is a great way to protect yourself from HIV even when exposed. However, it only works when taken correctly.

 If you're wondering how long protection lingers when you stop using PrEP as indicated, read on!

What is PrEP?

PrEP, or pre-exposure prophylaxis, is an oral pill that can be taken before exposure to HIV to protect you from infection. It can be taken regularly on a daily schedule or on demand.

On-demand PrEP needs to be taken following a 2-1-1 schedule to work. On the first day, 2-24 hours before exposure, you take a double dose of PrEP. Then, for the next two days or until one day after the last exposure, you take one pill per day. While this isn't quite as effective as daily PrEP, it still reduces the risk of HIV by 86%.

How does PrEP work?

PrEP works by inhibiting the HIV virus from entering the body's T-cells. Normally, HIV is able to spread by disguising itself and entering these specialized white blood cells. Then, it multiplies and inhibits their ability to perform their usual protective functions. 

PrEP effectively blocks the HIV virus from entering these cells, preventing the process of infection from taking place. This means that even if a PrEP user is exposed to HIV, it won't be able to infect the host. 

How long after stopping PrEP am I protected?

While PrEP may still have activity in the body for a week after your last dose, you shouldn't consider yourself protected from HIV after stopping PrEP. The risk of becoming infected quickly returns to normal after stopping PrEP. 

if you want to stop taking daily PrEP but would still like to be protected from HIV, you might consider using PrEP on-demand. This schedule can be more convenient for those who occasionally require protection but don't want to commit to taking a daily pill. 

Users can follow the 2-1-1 schedule whenever they anticipate an exposure. On demand PrEP is only recommended  for cis gendered men who have sex with men. It is not currently recommended for vaginal sex.

Another way to protect yourself if you don't want to keep taking PrEP every day is with PEP. PEP, which stands for post-exposure prophylaxis, can be taken after a sexual encounter to protect against HIV. The sooner you take it, the better, up to 72 hours after exposure. 

PEP is an emergency measure, so you should still try to take on-demand PrEP as indicated whenever possible. However, having PEP on hand in case of emergencies can offer peace of mind.

Key takeaways

There isn't definitive data to confirm how long you are protected after stopping PrEP. While there is likely increased protection for up to a week after stopping PrEP, this protection won't be as high during a normal course of PrEP. When taken correctly, PrEP offers a 99% reduction in HIV risk. During the week after stopping PrEP, there may still be protection, but not at this high level. 

Frequently asked questions

How long does the effect of PrEP last after you stop taking it?

It is unclear exactly how long the effect of PrEP lasts after you stop taking it. There is likely some protection for a little while after your last dose, but to be safe, it's best to use an on-demand PrEP schedule if you will be exposed to HIV again after stopping the daily use of PrEP. 

How long does PrEP take to be absorbed in the body?

PrEP is absorbed by the body's tissues quickly and can give protection a couple of hours after use when taken correctly. If taking daily PrEP, it's recommended to take it daily for a full week to maximize concentrations and protection. If taking it on-demand, a double dose is necessary on the first day to ensure enough protection to reduce the risk of HIV if exposed. 

How many days of PrEP can you miss?

If you miss a day of PrEP, continue taking it the next day at your usual time. Even if you miss two days, continuing your usual regimen the following day is best. However, if you miss a week or more of PrEP, you should start again from the beginning. This means taking another seven days of pills to build protection or starting with the 2-1-1 on-demand dosing schedule. 

Felix Team
Updated on:
March 8, 2023
Medically reviewed by
Dr. Sarah Lasuta
Family Physician, MD, CCFP

The views expressed here are those of the author and, as with the rest of the content on Health Guide, are not a substitute for professional medical advice, diagnosis, or treatment. If you have any medical questions or concerns, please talk to your healthcare practitioner.

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