How to take PrEP

Overview

PrEP can be taken as a daily tablet or “on-demand”.

Evidence shows that daily dosing is most effective. If taken seven out of seven days it is up to 99% effective.

If you take your PrEP pill every day, this will provide protection for a risk at any time during the period that PrEP is taken. Ideally you should start seven days before any risk. If in doubt, start with a double dose.

The “on-demand” method is only advised where the risk is from anal sex. (This was shown to be 86% effective overall in the French IPERGAY studay.) “On-demand” means you take PrEP just before and after a risk. This is also referred to as “event-based dosing” (EBD). There is less evidence for its effectiveness when this is taken less frequently than every week, e.g. 16 tablets per month.

If you are going on holiday and think you will be at risk, start seven days before and continue for a week after. If in doubt, start with two tablets.

Taking PrEP safely

However you choose to take PrEP, the most important thing is to take it reliably, start in good time and for as long as you may be having risky sex. Most people who have caught HIV despite using PrEP have done so because they stopped taking it too early or did not take it reliably enough.

If you choose to buy your own PrEP, the tests necessary to take PrEP safely are available via Umbrella. Before you start it is very important to make sure that you are HIV-negative and have had kidney function testing.

To book an appointment for these tests, please call us on 0121 237 5700.

Staff can also give information leaflets on PrEP when you attend the clinic.

Daily PrEP

If you decide to take your PrEP every day:

• Try to take your PrEP pills at a regular time each day. Pick a time you are likely to remember – for example, you may want to link it to a routine task, such as brushing your teeth
• Think about using a seven-day pill box so you can see If you have forgotten one
• Try to avoid missing pills, but if you do miss one, or even two, pills, it is still worth carrying on with taking PrEP. There is still likely to be enough medication in your body to protect against HIV
• Come to the clinic if you have missed more pills and are worried about any risks taken during this period. You may be at higher risk if you have missed three or more tablets in the week before a risk
• If you miss more than a week of pills and know you are going to have a risk soon, take a double dose (two pills), and then carry on with the dosage as normal
• Come to the clinic as soon as possible if you had a break from PrEP and had any risks during this time, to discuss whether you need post-exposure prophylaxis (PEPSE), if within 72 hours after the last risk, and to discuss the best timing for a follow-up HIV test and STI screen

On-demand PrEP

If you are taking PrEP on-demand, try to make sure that there is enough of the medicine in your body at the time you have sex. Remember, on-demand is only advised where the risk is from anal sex.

To do this:

• take a double-dose 2 – 24 hours (ideally 24 hours) before you anticipate a risk. It’s better to take a dose you don’t need than miss the opportunity to start in good time
  take the next dose ideally 24 hours after the double dose, at a time you are likely to remember
• carry on taking PrEP daily at your regular time while any risk continues, and try not to miss any doses
• after the last risk, carry on taking PrEP every day at your regular time for another 48 hours, that is for at least two further doses after the last risk

The study evidence for on-demand PrEP is best for those taking PrEP most weeks. If you have not taken pills for some time it may take longer for the pills to build up in your body. In this case, try and start as early as possible and not just 2 hours before potential risk. A week is ideal if you are starting after gap of more than seven days.

Don’ts

• Try not to miss pills, or give up on PrEP just because you were late with the first dose
  • The drugs will still give you some protection so the sooner you take them the better
  • Start with the double dose (two pills), and continue daily
  • Go to a clinic as soon as you can to discuss the need for post-exposure prophylaxis (PEPSE)
• Don’t take more than one double dose within seven days
  • If the next risk is less than seven days after the last dose, take just one tablet and continue as usual
  • Carrying on taking double doses after the first dose within a seven-day period isn’t necessary and may do you harm

Dos

• Come to the clinic as soon as possible if you have had a break from PrEP and need advice as to how to restart
  • If you have had high-risk sex, you should come as soon as possible, and ideally after no longer than 72 hours later