HIV Pre-Exposure Prophylaxis (PrEP)

If you're HIV negative, pre-exposure prophylaxis (PrEP) may be suitable for you to reduce your risk of getting HIV. PrEP is available as a tablet, which you take before and after you have sex and are exposed to HIV.

PrEP is available as a tablet, which you take before and after you have sex and are exposed to HIV.

Taking PrEP before being exposed to HIV means there’s enough drug inside you to stop HIV if it gets into your body.

The PrEP tablet is a combination of two drugs: tenofovir and emtricitabine.

The drugs used in PrEP are also commonly taken by people with HIV as treatment.

PrEP is highly effective when taken correctly. PrEP has been shown to be more than 99% effective at preventing HIV infection.

PrEP is one of many possible HIV prevention methods and can be used in combination with condoms.

PrEP is also safe to use in conjunction with many methods of contraception, including all hormonal contraception (ring, patch, the pill, or an implant).

PrEP can be taken by people at risk of infection with HIV to prevent getting HIV.

PrEP can be beneficial for anyone (any gender, any sexual orientation) who have sex without a condom, as well as others at high risk, including HIV negative partners of people with HIV that is not virally suppressed.

If you’re thinking about taking PrEP, you can talk with a sexual health clinic who can help you decide if it’s right for you and what you need to do before you start taking it.

Some of the advantages of PrEP are:

  • PrEP is extremely effective when taken properly. PrEP has been shown to be more than 99% effective at preventing HIV infection.
  • PrEP can reduce your risk of getting HIV if you have sex in situations where condoms are not used
  • You can take PrEP daily (this is often called ‘daily dosing’) or only when needed (this is often called ‘on-demand’ or ‘event based’ dosing)
  • You can use PrEP if you are pregnant or breastfeeding
  • PrEP is also safe to use for people who are taking hormone treatment (eg. Those who are transitioning gender)

Some of the disadvantages of PrEP are:

  • You have to remember to take the pill as prescribed
  • PrEP won’t protect you from STIs (except HIV) or an unwanted pregnancy, so you may choose to use condoms as well.
  • If you’re using PrEP it is important to have regular STI testing every three months

A minority of PrEP users experience mild side effects for a short period of time:

  • Some people experience side effects, such as nausea, headaches and tiredness
  • Rarely, PrEP can affect kidney function. As a precaution, people taking PrEP have regular kidney function tests

If side effects persist, you should continue taking PrEP and speak to your healthcare provider. 

In England, PrEP is available from sexual health clinics. To find out more, please check the website for your local service.

In Northern Ireland, PrEP is available as part of a pilot programme. See https://www.sexualhealthni.info/pre-exposure-prophylaxis-prep-hiv more for information. 

In Scotland, PrEP is available on the NHS for anyone at high risk of acquiring HIV. See prep.scot for more information.

In Wales, PrEP is available on the NHS, through the Wales PrEP Project, for anyone at high risk of acquiring HIV. See friskywales.org/wales-prep-project.html for more information.

Some people choose to buy PrEP online or from private clinics. If you’re thinking about taking PrEP, you can talk with a sexual health clinic who can help you decide if it’s right for you and what you need to do before you start taking it. Further information on PrEP can be found via i-Base: https://i-base.info/guides/prep

PrEP can be used in two different ways:

  • taken regularly (one tablet per day). This is often called ‘daily dosing.’
  • only taken when needed (2 pills between 24 and 2 hours before sex, followed by one pill 24 and 48 hours later). This is often called ‘on-demand’ or ‘event based’ dosing.

Both methods have been shown to be highly effective, but on-demand dosing has only been studied in gay, bisexual men and transgender women.

Because PrEP is for people who are HIV negative, you will need to get an HIV test before starting PrEP and you may need to get other tests to make sure it’s safe for you to use.

If you take PrEP, you’ll need to meet with your healthcare provider every 3 months for follow-up, regular STI testing and to update your prescription.

If you would like to use PrEP, it is recommended that you talk with a sexual health clinic who can help you decide if it’s right for you, which dosing regimen would suit you best, and what you need to do before you start taking it.

Further information on HIV and AIDs, including HIV prevention, can be accessed via: https://www.nhs.uk/conditions/hiv-and-aids/

Further information on PrEP can be found via i-Base: https://i-base.info/guides/prep

Information last updated:
Next planned review by:

This website can only give you general information about contraception. The information is based on evidence-guided research from the World Health Organization and The Faculty of Sexual and Reproductive Healthcare of the Royal College of Obstetricians and Gynaecologists. All methods of contraception come with a Patient Information Leaflet which provides detailed information about the method.

Remember – contact your doctor, practice nurse or a contraception clinic if you're worried or unsure about anything.