You should always take PrEP as instructed by your clinician in order to make sure that it’s providing full protection, and that you’re using it safely.
There are a couple of different ways to take PrEP. The first is if you’re being prescribed PrEP for daily use and the second is if you’re having it prescribed for on-demand use.
For daily use:
- One tablet a day should be taken with food.
- Take it at the same time every day.
- Different dosages might be prescribed depending on whether you’re an adolescent or an adult.
If you forget to take your PrEP:
- If you remember within twelve hours, take it and carry on with your next dose as normal.
- If it’s longer than twelve hours, skip the dose and continue with your next one at the right time the following day.
For on-demand use:
On-demand PrEP is basically as it suggests. This is where you only take it when you know you’ll have sex with someone who is HIV positive or their HIV status is uncertain. You’ll take fewer tablets over a shorter time frame – before and after sex.
There are some rules to stick to to make sure it works, but it’s highly effective in preventing HIV exposure for high-risk men who have sex with other men .
- Take a double dose (two pills) 2-24 hours before sex.
Then continue as follows:
- Take just one pill exactly 24 hours after your initial double dose.
- Take one more pill another 24 hours after that.
One of the best ways of remembering this dosage is to think ‘2-1-1’.
However you’re taking PrEP, whether daily or on-demand, you’ll need to take a HIV test every three months to make sure you’re still testing HIV negative. In the event you test positive, you’ll need to stop taking PrEP and discuss other options with your clinician.
How long does PrEP take to work?
PrEP will reach it’s maximum protection at different rates depending on the kind of sex you’re having. For instance, if you’re receiving receptive anal sex (bottoming) then you’ll get maximum protection after seven days of continual use. If you’re receiving receptive vaginal sex then it can take up to 21 days of continuous daily use to reach the same protection.
At the moment there isn’t any clinical data available on protection for insertive anal sex (topping) or insertive vaginal sex.
Studies show that taking PrEP on-demand is very effective at stopping the spread of HIV. If you take the recommended four doses (2-1-1) in the preceding 24 hours before, and the following 48 hours after sex, you should get maximum protection against contracting HIV.
What about on-demand PrEP?
On-demand PrEP is the option to take if you don’t have a partner who is HIV positive, but you’re anticipating the possibility of having casual sex with people who could be.
It involves you taking two pills, 2-24 hours before sex, then a further pill 24 hours after, followed by one final dose 24 hours after that.
It’s highly effective at helping to prevent HIV infection in men who are at high risk, who have sex with other men. It offers a viable solution to taking PrEP every single day and gives protection against HIV infection. However, this method is only suitable for anal sex and not for vaginal or frontal sex.
Do I still need to use a condom with PrEP?
Yes, you’ll still need to use a condom with PrEP. As PrEP only provides protection against HIV, you’ll still need barrier protection if you sleep with someone who might have a different STI.
Barrier protections like this, whether it’s a male or female condom, can provide 98% safe protection against HIV and other STIs when used correctly.
PrEP isn’t a form of contraception, so you’ll still need to use a condom to protect against pregnancy, or consider the contraceptive pill if you’re female.