What is PEP?
When people have been put at risk of HIV there’s a treatment called PEP that may prevent HIV infection after the virus has entered the body:

  • PEP stands for Post Exposure Prophylaxis

PEP is a month long course of HIV drugs that someone takes very soon after sex which had a risk of HIV transmission.

  • It involves taking anti-HIV drugs for four weeks
  • The drugs are the same ones taken by people with HIV, and for PEP to work they must be taken for four weeks. The sooner PEP is started, the more likely it is to work; within 24 hours is best, but no later than 72 hours (three days). After 72 hours PEP is unlikely to work.
  • It must be started as soon as possible after unsafe sex or a condom not working – ideally within 24 hours but definitely within 72 hours (three days)
  • There can be side effects such as diarrhea, nausea and prolonged headaches
  • PEP isn’t guaranteed to work.

PEP is not a ‘morning after’ pill to stop HIV as it is not taken just once but must be taken every day for 28 days. If someone stops taking it before 28 days there is a possibility that it will not have worked.

Where can I get PEP?

Contact a sexual health clinic. Click here for details.
If these clinics are closed, please go to Addenbrooke’s or Hinchingbrooke Accident and Emergency (A&E) department

Addenbrooke’s Hospital
Hills Road
Switchboard: 01223 245151


Hinchingbrooke Hospital
Hinchingbrooke Park
PE29 6NT
Switchboard: 01480 416416

PEP is not a cure for HIV and is not guaranteed to prevent HIV from taking hold once the virus has entered the body. Condoms and lube for sex remain the most efficient way of staying safe from HIV.
Also, if you have been at risk from HIV, there is a chance you may have picked up other infections as well. You can be checked for these confidentially at any sexual health clinic.
If you have had sex with someone in the last three days (72 hours) who is HIV positive or who has a high chance of having HIV then taking a short course of drugs may help to prevent infection. It is more effective the sooner you take it and may be considered if:

  • you had oral sex with someone who has HIV or is at high risk of having HIV and they ejaculated in your mouth
  • you had unprotected vaginal or anal sex with someone who either has HIV or is at high risk of having HIV

Remember, DHIVERSE is here for you.
You can contact us for more information about PEP but please remember we are only open Monday to Friday. If you would like to have a chat or need support if you are prescribed PEP then please call 01223 508805 or email