PEP: Post Exposure Prophylaxis for HIV
PEP (post exposure prophylaxis) is a 28-day course of anti-HIV medication that can stop HIV infection after a possible exposure. It works best when started as soon as possible, ideally within 24 hours, and must be started within 72 hours. If you think you have been exposed to HIV, call Sunshine Clinic now on 0330 097 5362. Telephone advice and bookings are available 24/7.
What is post exposure prophylaxis?
Post means after. Exposure means a situation where HIV may have entered your bloodstream. Prophylaxis means treatment to prevent an infection. After HIV enters the body it takes a short time, from hours to a few days, before infection becomes permanent. PEP uses anti-HIV medicines during this window to try to stop the virus taking hold.
PEP was first used for healthcare workers after needlestick injuries. It is now also prescribed, under strict UK guidelines, after possible sexual exposure to HIV.
When should you take PEP?
The sooner PEP is started, the more likely it is to work. Current UK guidance is to start as soon as possible after exposure, ideally within 24 hours and no later than 72 hours (3 days). After 72 hours PEP is unlikely to work and is not usually prescribed.
You may need PEP after:
- sex without a condom, or a condom splitting or coming off, with a partner who has HIV or whose HIV status is unknown
- sexual assault
- sharing needles or injecting equipment
- a needlestick injury or blood splash into the eyes, mouth or broken skin
PEP is no longer recommended if your partner has HIV but has been on treatment with an undetectable viral load for more than 6 months, because HIV cannot be passed on in this situation.
PEP medication
The recommended PEP course in the UK is a combination of Truvada (emtricitabine and tenofovir) and raltegravir, taken for 28 days. Your doctor may prescribe a different combination if it is more suitable for you, for example if you take other medicines. It is important to take every dose and complete the full course.
PEP side effects
Most people complete PEP without serious problems. The most common side effects are:
- nausea or feeling sick
- diarrhoea
- headache
- tiredness
These usually settle within a few days. If side effects are affecting you, contact us and Dr Sood will review your treatment.
How to get PEP at The Sunshine Clinic
Sunshine Clinic is appointment only and is not a walk-in service. Call 0330 097 5362 at any time of day or night. Dr Prabhat Sood, Consultant Physician in Genitourinary and HIV Medicine, will assess your risk and whether PEP is right for you.
At your consultation the doctor will ask about:
- when the exposure happened
- the type of sex or contact involved and whether a condom was used
- anything known about the other person, including their HIV status and treatment
- any needlestick injury or shared injecting equipment
- your medical history and any medicines you take
You will be offered an HIV test before starting PEP. This checks you did not already have HIV, because taking PEP when already HIV positive can cause drug resistance. You will receive counselling before your test, before PEP and after PEP.
Other care after a possible exposure
Sexual exposure can also carry a risk of other sexually transmitted infections and pregnancy. We will offer testing for other STIs and, where pregnancy is possible, emergency contraception.
Needlestick injuries and shared injecting equipment can also pass on hepatitis B and hepatitis C. Sunshine Clinic offers hepatitis B prophylaxis, including an accelerated course of hepatitis B vaccination and, after high-risk exposure, hepatitis B immunoglobulin. There is no prophylaxis for hepatitis C, so blood tests are repeated at 3 and 6 months. Read more about hepatitis B and C.
Follow-up after PEP
PEP is not guaranteed to work, which is why follow-up testing is essential. You will need a final HIV test 8 to 12 weeks after the exposure to confirm you do not have HIV. Use condoms until you have your final result.
Staying safe after PEP
PEP is an emergency treatment, not a replacement for condoms. Condoms used correctly remain one of the most effective ways to prevent HIV and other STIs. If you are at ongoing risk of HIV, ask us about PrEP (pre-exposure prophylaxis) at your follow-up.
PEP: frequently asked questions
How long do I have to take PEP?
PEP is a 28-day course. It should be started as soon as possible after exposure, ideally within 24 hours and no later than 72 hours.
Can I get PEP after 72 hours?
No. After 72 hours PEP is unlikely to work and is not usually prescribed. Call us for advice and an HIV testing plan.
Does PEP always work?
No. PEP greatly reduces the chance of HIV infection but is not 100% effective. It is more likely to fail if it is started late or doses are missed.
Where can I get PEP?
PEP is available privately at Sunshine Clinic by appointment. On the NHS it is available from sexual health clinics during opening hours and from hospital A&E departments out of hours.
Do I need an HIV test before PEP?
Yes. An HIV test before starting PEP checks you did not already have HIV, as PEP in someone who is HIV positive can cause drug resistance.