How to use PrEP
Different ways to use PrEP
There are different ways to use PrEP based on your preferences and circumstances.
If you have sex on a regular basis or want 24 hour protection against HIV, daily PrEP could be right for you. Daily PrEP involves taking a PrEP pill once a day, every day for as long as you decide. Daily PrEP is suitable for anal, and vaginal or front hole sex, and injecting drug use.
If you have sex less than twice a week and you're able to plan ahead or delay sex for at least 2 hours, on-demand PrEP could be right for you. On-demand PrEP involves using PrEP for a shorter period of time when you decide you want to be protected. On-demand PrEP is only suitable for anal sex and doesn't provide adequate protection for vaginal or front hole sex, or injecting drug use.
For choosing between daily PrEP and on-demand PrEP, this guide provides more details: Daily or on-demand PrEP? — How to choose what’s best for you
Remember, using PrEP doesn't have to be forever. Talk to your doctor before stopping, restarting or changing the way you use PrEP to make sure it's right for you and your circumstances.
Daily PrEP is suitable for anal, and vaginal or front hole sex, and injecting drug use.
Using daily PrEP is as simple as taking one PrEP pill a day, every day. It doesn't matter what time of day you take your PrEP pill and it's OK if it's not exactly the same time every day. Just be sure to take one PrEP pill every 24 hours.
If you accidentally take 2 PrEP pills in one day, it's OK. Taking 2 PrEP pills is not harmful.
Starting daily PrEP
Starting daily PrEP is different for different people. For cisgender men who have sex with men, daily PrEP can be started with a double dose (2 pills) at least 2 hours before sex.
For everyone else (trans and gender diverse people, cisgender women and men who have sex with women), it takes 7 days of daily dosing for PrEP to build up optimal levels of protection against HIV in your body. So it's important to use other forms of HIV prevention for any sex you have in your first week of using daily PrEP.
Missing a dose of daily PrEP
Although it's best to use daily PrEP every day, missing a dose sometimes happens. If you do miss a dose, you don't need to take extra PrEP pills. Simply start your routine again as soon as you remember later that day or the next day.
For people having anal sex, PrEP still offers extremely high levels of protection even if you miss one dose. However, if you're missing more than one dose and taking less than 4 pills per week, PrEP may not be able to protect you against HIV.
For people having vaginal or front hole sex, using PrEP every day is especially important. This is to ensure sufficient levels of drug concentration in vaginal/cervical tissues.
Stopping daily PrEP
If you want to take a break or discontinue daily PrEP for any reason, it's recommended to consult your doctor first.
Stopping daily PrEP is different for different people. For cisgender men who have sex with men, daily PrEP can be stopped by continuing to use daily PrEP for 2 days after your last possible exposure to HIV.
For everyone else (trans and gender diverse people, cisgender women and men who have sex with women), it's recommended you keep using daily PrEP for 28 days after your last possible exposure to HIV.
Before restarting PrEP, check in with your doctor for routine tests, especially if you have had any possible exposures to HIV in the meantime.
On-demand PrEP is only suitable for anal sex and doesn't provide adequate levels of protection for vaginal or front hole sex, or injecting drug use. For vaginal or front hole sex, or injecting drug use, daily PrEP is recommended instead.
Australia's clinical guidelines for PrEP consider on-demand PrEP is only suitable for cisgender men who have sex with men. Daily PrEP is recommend for everyone else (trans and gender diverse people, cisgender women and men who have sex with women).
Using on-demand PrEP requires good understanding of the dosing schedule and following it carefully. Timing is important and it is crucial to not miss any doses when using on-demand PrEP or it might not be able to protect you against HIV.
Using on-demand PrEP involves:
taking a double dose (2 pills) between 2 and 24 hours before sex; then
taking one more pill 24 hours after the first dose; then
taking one final pill 24 hours after the second dose
For example, if you're planning to have sex on Friday at or after 7:00pm, take a double dose (2 PrEP pills) on Friday by 5:00pm at the latest. Then take one more PrEP pill on Saturday at 5:00pm. Then take one final PrEP pill on Sunday at 5:00pm.
If you continue having sex on a day while you're still using on-demand PrEP, keep taking one PrEP pill every 24 hours, stopping only once you've had 2 days of using PrEP without having any sex.
If you miss a dose of on-demand PrEP or have been unable to follow the dosing schedule for any reason, it's best to seek medical attention as soon as possible, as you may be offered PEP to ensure you stay HIV negative.
As is the case with using any medicine, there could be side effects. But not everybody gets them. The small number of people who do may be surprised by how uneventful they are and how quickly they go away.
There’s a small chance you might experience very mild symptoms such as a stomach upset, tiredness or nausea for the first few days. None of these stay for long. Some people report vivid dreams or restlessness for a short time too. If you do experience mild side effects when first starting PrEP, taking your pill after a full meal may help avoid them.
A very small number of people have experienced challenges with kidney function and bone density while using PrEP. This is typically due to pre-existing medical conditions or other health factors. As a precautionary measure your doctor will regularly monitor your health while using PrEP. These side effects aren't common and are known to reverse when discontinuing PrEP.
PrEP is a very well tolerated medicine with minimal side effects. Start a conversation with your doctor about these or anything else you'd like to know. You can also ask Australia's largest online PrEP community in the PrEP'D For Change Facebook group.