PEP (Post Exposure Prophylaxis)

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1. How to get PEP
2. PEP's effectiveness
3. Potential side effects
4. PEP and unsafe sex
5. Instructions for accessing PEP

PEP is a course of HIV medication which you can take if you have been at risk of HIV infection. The course of HIV medication lasts 28 days and, if taken within 72 hours of putting yourself at risk, may be able to prevent you from becoming infected with HIV. PEP stands for Post Exposure Prophylaxis – in other words it is a form of protection (against HIV) that you can take after you have taken a risk or had a condom break on you.

How to get PEP

You can get PEP at a sexual health clinic or in the Accident and Emergency department of some hospitals. A&Es are especially important at weekends because most sexual health clinics will not be open. You must start PEP within 72 hours of putting yourself at risk of HIV, though the sooner you start PEP the more likely it is to be effective. Because HIV medication is expensive clinics will not prescribe PEP unless they feel that there is a very real chance that infection will take place if they don’t. PEP will not be given to someone who is already HIV positive and so if you ask for PEP they will give you an HIV test. If you are HIV negative they will probably try to establish what your risk of infection is and this will depend on the likelihood of your partner being HIV positive and how risky the sex you had was. If you know that your partner was HIV positive, and he is willing to come to the clinic or hospital with you, it may be easier for you to access PEP.

This website provides information about London clinics. This symbol indicates that a clinic offers PEP. Services provided by clinics are subject to change, so it is recommended that you call in advance to check that a clinic can provide you with PEP.

PEP’s effectiveness

Research indicates that PEP can prevent infection with HIV, but it is not 100% effective.1 PEP is more likely to be effective when the treatment starts shortly after the risk occurred and most clinics will not put someone on a course of PEP any later than 72 hours after HIV exposure (risk). The sooner after the risk you begin PEP, the better the chance that it will work.

Potential side effects

People taking PEP are likely to experience the same kind of side effects as HIV positive people who are beginning to take HIV medication. Common side effects include diarrhoea, nausea, headaches and tiredness. As a result of these side-effects many people fail to complete the full course of PEP. In rare cases more serious side effects, such as liver damage, can occur.

PEP and unsafe sex

PEP is not a substitute for consistent condom use. Studies suggest that most men who have taken PEP are likely to have less unsafe sex afterwards and are unlikely to seek PEP again.2 This is because taking PEP is not an easy option. If you take PEP you will have to cope with the same side effects that men on HIV medication suffer, as well as the hassle of having to remember to take your meds at set times during the day.

PEP will not make you immune to HIV infection. If you have unsafe sex while you are taking PEP or after you have finished a course of PEP, you may become infected with HIV.

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Instructions for accessing PEP

If you believe that you need PEP, the following section explains what you should do. It will be helpful to bring this information with you to the clinic.

Act immediately. The sooner you start PEP, the more likely it is to be effective. If you put yourself at risk at the weekend do not wait until the Monday to act.

Try to contact your local sexual health clinic first. Ask to speak to a sexual health nurse or health adviser urgently. If this isn’t possible, you should explain that you think you’ve been exposed to HIV and want to talk to someone about being given PEP. Ask for the names of whoever you speak to and write them down – this could speed things up when you go to the clinic later.

If you cannot find a clinic that is open (most aren’t open at weekends) you can go to an Accident & Emergency (A&E) department of a local hospital. If the A&E department is part of a hospital with its own HIV ward or clinic, it should be easier to get PEP there as staff from that clinic will be knowledgeable about PEP and the medication will be available.

What to do at a Clinic or Hospital's Accident & Emergency (A&E) Department
Go to the reception and explain you want to see someone urgently about PEP (Post Exposure Prophylaxis) to prevent HIV infection. If you have already spoken to someone on the phone, give their names. If you haven’t, tell reception staff that you think you’ve been exposed to HIV and you want to speak to a nurse or health adviser about being given PEP.

Tell them you need to see someone as soon as possible and be determined. Don’t agree to come back later; while you must start PEP within 72 hours of putting yourself at risk of HIV. The sooner you start PEP the more likely it is to be effective.

If you are at the A&E department of your local hospital it may help to ask them to call the ‘on-duty HIV registrar’ who will have experience in PEP and HIV.

Speaking to a doctor
When you get to speak to a doctor or nurse, tell them you want PEP and give details of when and how you were at risk of HIV infection.

PEP has only been used for sexual exposure to HIV since guidelines were issued in 2004. If the doctor you are speaking to is unfamiliar with PEP, refer him or her to the British Association for Sexual Health and HIV (BASHH) guidelines for post-exposure prophylaxis after sexual exposure (PEPSE) to HIV. These guidelines can be accessed at: http://www.bashh.org/documents/58/58.pdf

There will be a number of questions to answer so that the doctor can decide if you need PEP. It is important to provide honest answers. You will be asked about the following:

1. When you think you were at risk.

2. The sex you had (e.g. was it oral or anal sex; was semen involved, was a condom used).

3. The person you had unsafe sex with (to try and determine if they had HIV or not).

These questions are asked to try to establish what your risk of infection is. This will depend on the likelihood of your partner being HIV positive and how risky the sex you had was. If you know that your partner was HIV positive it may be easier for you to get PEP, especially if he is willing to go to the clinic or hospital with you.

Taking an HIV test
PEP will not be given to someone who is already HIV positive and so they will need to give you an HIV test to check you don’t already have HIV. PEP won’t be offered if someone refuses to be tested. You must also agree to be tested after you have finished the course of PEP to see if it’s worked.

What drugs will they use?
The drugs used for PEP are a triple combination of anti-HIV drugs.3 These are commonly selected from:

Either

AZT (also called zidovudine) and 3TC (lamivudine) – also available in a combination pill called Combivir,

Or

Tenofovir and FTC (embtricitabine) – also available in a combination pill called Truvada

Plus one of the following:

lopinavir or fosamprenavir or saquinavir

However, other drugs may be used for PEP. These drugs should be taken together for one month.

Taking PEP
The drugs used for PEP are expensive and powerful so the decision to offer treatment is not taken lightly.

PEP uses the same drugs that treat HIV infection so you are likely to experience the same kind of side effects as people who are beginning to take HIV medication. Common side effects include diarrhoea, nausea, headaches, and tiredness. In rare cases more serious side effects, such as liver damage, can occur. The doctor will need to explain the effects of these medications before you start PEP.

Some people often stop taking PEP or miss doses due to these side effects but this stops the treatment from working. In order to have the greatest chance of success, every dose of PEP must be taken as prescribed. If you find you have missed a dose, take it as soon as you remember it. Do not just wait and take a double dose at the time you are next due – this can be dangerous.

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1 Roland ME et al. Seroconversion following non-occupational post-expsure prophylaxis. Eleventh Conference on Retroviruses and Opportunistic Infections, San Francisco, poster 888, 2004.

2 Martin JN et al. Use of post-exposure prophylaxis against HIV infection following sexual exposure does not lead to increases in high-risk behaviour. AIDS 18: 787-792, 2004.

3 BASHH Guideline. UK Guideline for the use of post-exposure prophylaxis for HIV following sexual exposure. International Journal of STD & AIDS 2006; 17: 81–92