How to use PrEP

Different ways to use PrEP

There are different ways to use PrEP depending on your circumstances and preference.


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 per day, every day for as long as you decide. Daily PrEP is suitable for anal, and vaginal or front hole sex.


If you have sex occasionally and you're able to plan your sexual encounters between two and 24 hours in advance, 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. However, on-demand PrEP is only suitable for anal sex and doesn't provide suitable levels of protection for vaginal or front hole sex.

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

Daily PrEP is suitable for both anal and vaginal or front hole sex.


Using daily PrEP is as simple as taking one PrEP pill per 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 once every 24 hours.


If you accidentally take two PrEP pills in one day, it's OK. Taking two PrEP pills is not harmful.


It takes seven days of daily usage 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 during your first week using daily PrEP.


Although it's best to use PrEP every day, missing a dose sometimes happens. If you do, 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 four pills per week, PrEP may not be able to offer protection against HIV.


For anyone 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.


If you want to take a break or discontinue daily PrEP for any reason, it's recommended you keep using daily PrEP for 28 days after your last possible exposure to HIV and consult your doctor. Before restarting PrEP, it's also important to check in with your doctor for routine tests.

On-demand PrEP

On-demand PrEP is only suitable for anal sex and doesn't provide suitable levels of protection for vaginal or front hole sex. For vaginal or front hole sex, daily PrEP is recommended.


Using on-demand PrEP requires good understanding of the dosing schedule and following it carefully. It is especially important not to miss any doses when using on-demand PrEP or it might not be able to offer protection against HIV.


Using on-demand PrEP involves:

  • taking two pills together between two and 24 hours before you have 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 around or after 7:00 pm, take two PrEP pills on Friday by 5:00 pm at the latest. Then take one more PrEP pill on Saturday at 5:00 pm. Then take one final PrEP pill on Sunday at 5:00 pm.


If you have more sex on a day while you're still using on-demand PrEP, continue taking one PrEP pill every 24 hours, stopping only once you've had two days using PrEP without having any sex.

Possible side effects

As is the case with using any medicines, there could be side effects. But not everybody gets them and the small number of people who do are often surprised by how uneventful they are and how quickly they go away.


There’s a small possibility you might experience very mild symptoms such as a brief stomach upset, tiredness or nausea for the first few days, though none of these stay for long. Some people have reported vivid dreams or restlessness for a short time too.


Even if you do experience anything, taking PrEP after a full meal can often help avoid any temporary side effects when first starting PrEP.


A very small number of people have experienced challenges with kidney function and bone density while using PrEP, typically because of pre-existing medical conditions or other health factors. As a precautionary measure, your doctor will regularly monitor these for you. These particular side effects are uncommon and known to reverse fully when discontinuing PrEP.


PrEP is a very well tolerated drug with minimal side effects. Start a conversation with your doctor or the online community at the PrEP'D For Change Facebook group about these or anything else you might be curious about.


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