
PrEP (pre-exposure-prophylaxis) is a medication taken by HIV-negative people that prevents you from getting HIV.
Taking PrEP before being exposed to HIV means there’s enough drug inside you to block HIV if it gets into your body – before it has the chance to take hold. It’s highly effective at stopping HIV from being transmitted when taken correctly.
PrEP offers protection during frontal and anal sex. It’s safe to use for trans masculine and non-binary people and is effective regardless of any gender-affirming surgeries that you’ve had.
A long-acting injectable PrEP has been approved by the Food and Drug Administration (FDA) but it is not yet available in the UK.
Is PrEP right for you?
PrEP might be right for you if you’re HIV negative and have sex in a variety of situations where condoms are not easily or always used. It gives you empowerment, particularly if you are a receptive partner, or bottom, by taking control over protecting yourself from HIV transmission.
Quote textI find it hard to negotiate condoms when I have sex with cis men. And sometimes it happens so fast. By taking PrEP I feel a little more in control of my health.
How to take PrEP
The way you take PrEP depends on the type of sex you have, but most people choose to take PrEP every day.
PrEP can be taken in different ways to protect against HIV:
- Daily: taking one pill a day, starting with a double dose.
- Four pills a week: taking four pills a week consistently.
- On-demand/ event-based: taking PrEP only around the time you have sex. Pills are taken a few hours before sex and for up to seven days after.
On-demand/ event-based PrEP has different dosing recommendations depending on the type of sex you are having:
- Receptive anal and insertive vaginal/neovaginal or anal sex: PrEP started with a double dose (two pills) 2-24 hours before sex, one tablet 24 hours later and a further tablet 48 hours after that.
- Receptive vaginal/neovaginal sex: PrEP started with a double dose (two pills) 2-24 hours before sex, one tablet daily for seven days after.
PrEP is very safe and serious side effects are very rare. A few people experience nausea, headaches or tiredness which tend to only last a few days or weeks.
The drugs most commonly used for PrEP are emtricitabine and tenofovir (which are combined in a single tablet).
PrEP and STIs
PrEP only protects against HIV, not other sexually transmitted infections (STIs). If you’re taking PrEP, using condoms helps prevent other STIs.
Interaction with hormones
The British HIV Association (BHIVA) guidelines note that there are no known interactions between PrEP and gender-affirming hormones. PrEP will not stop any hormones you are taking from working.
PrEP does not cause fat redistribution in the body or face.
You can take hormone replacement therapy for menopause while on PrEP.
Before taking PrEP
Before taking PrEP, have a full sexual health screen at a local clinic, including an HIV test and a test for kidney function.
While taking PrEP, test for HIV and all other STIs every three months.
Where to obtain PrEP
You can get PrEP for free on the NHS from a sexual health clinic.
PrEP can also be bought from a reliable source.
PrEP and contraception, conception and breast/chest feeding
When you take PrEP, you can safely:
- Get pregnant. PrEP prevents HIV, not pregnancies. Continue to use contraception to avoid pregnancy.
- Take hormonal birth control. It's safe and both will work if taken correctly.
- Conceive and carry a baby. It's safe for you and your baby.
- Chestfeed.
If you want to stop taking PrEP
If you want to stop taking PrEP for any reason and are taking it daily, you should continue taking it for seven days after the last time you have sex without a condom. If you are taking ‘on demand dosing’ you should continue taking PrEP for the recommended time after sex, either 2 or 7 days after the last time you have sex without a condom.
Get tested for HIV before you start taking it again. If you have acquired HIV and begin taking PrEP, you may develop resistance to the drugs used for PrEP which could affect future treatment options if you are HIV positive.
If you are living with hepatitis B, be aware that PrEP can suppress the virus – you should always use daily dosing of PrEP and should not stop taking PrEP until you've got advice from your doctor.
Find out more about PrEP
PEP
PEP (post-exposure prophylaxis for HIV) is a treatment that can stop an HIV infection after the virus has entered a person’s body (for example, if you’ve had sex and the condom fails). To work, PEP must be taken within 72 hours (three days), and ideally should be taken within 24 hours.
If you think you've put yourself at risk of HIV it might be worth accessing post-exposure prophylaxis (PEP).
You can access PEP from a sexual health clinics or A&E. Tell your doctor if you're taking any hormones and any other drugs or medications.