When you first start PrEP, or if you’re restarting after a break, you should have a HIV test to make sure you are still HIV negative. You should also test for hepatitis B and start a course of vaccination if you haven’t had it before. PrEP contains a treatment that is also used for hepatitis B, so it’s important to know whether you have hepatitis B before you start.
Come and speak to us when you are ready to start PrEP. We’ll ask you some questions about your medical history, check any medications you take and do the tests for HIV, hepatitis B and other sexually transmitted infections. We’ll also do a check of your kidney function too.
Taking one PrEP pill each day gives you continuous protection against HIV and it works equally well whether your risk is from anal or vaginal/front hole sex. We recommend that you take your pill around the same time each day, you can take it with or without food. After you start, you should be taking your pills for seven days in a row before you can be sure that you are adequately protected. Alternatively, if your risk is from anal sex only (whether you’re top, bottom or both) you can get faster protection by starting with a double dose (2 pills) – this means your protection will start as quickly as 2 hours after you start. You should then continue with a single pill each day from 24 hours later.
For some people, PrEP works when it’s taken just around the time that unprotected sex happens. We call this “on-demand” PrEP or “event-based” dosing. If your risk is from anal sex only, studies show that taking PrEP this way works just as well as a daily dose. But you cannot take on-demand PrEP if your risk is from vaginal/front-hole sex, or if you have a hepatitis B infection.
For event-based dosing, start with a double dose (2 tablets of PrEP). You’ll be protected against HIV from 2 hours later. You then take a single dose every 24 hours at around the same time of day. Continue the single dose for at least 2 days after the last time you had sex.
Event-based dosing works well for people who know in advance when they are likely to have sex and have access to their pills when they do. Sex is not always predictable. Think about whether event-based dosing suits you. If you do choose event-based dosing, you need to be extra careful not to miss pills. If you are unsure, daily-dosing is most likely better, at least until you have time to decide.
PrEP only works when it’s taken regularly so try to avoid missing any doses. Aim to take it at the same time each day – pick a time that works for you. It might help to link it with another daily activity. You can purchase a pillbox from most pharmacies – they make it easy to see if you have missed any. Setting an alarm on your phone may also help.
When you’re on PrEP, having regular check-ups for HIV and STIs is essential. We recommend every 3 months as a minimum, or you can come and see us sooner if you have symptoms. At least once a year we’ll do checks on your kidney function too, as they can in very rare cases be affected by PrEP.
PrEP is safe and effective for trans and non-binary people. If your only risk is from anal sex then you can choose either daily or event-based PrEP. If you have vaginal/front hole sex then you’ll need to use daily PrEP. It won’t affect hormone medication. 56T is our dedicated weekly service for trans and non-binary people, where you can talk about PrEP and get regular check-ups.