HIV PEP (Post-Exposure Prophylaxis)

Taken within 72 hours of possible exposure to HIV, this is the most effective way of preventing HIV after exposure to the virus.

Method of Prevention: Oral antiviral tablets

Length of Medications: 28 days course

Further actions: HIV test in 28 & 90 days

Price: £550 (includes consultation fee + baseline instant HIV test & instant Hepatitis B sAg test)

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1. Discuss your risk of getting HIV

And any questions you may have.

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2. Conduct a baseline HIV test

To ensure you don’t already have HIV.

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3. Provide you with PEP tablets

And call you back at 28 days post-exposure for a HIV test.


What is PEP?

PEP (Post-Exposure Prophylaxis) is a combination of anti HIV medications taken for 28 days with an aim of aborting the settlement of virus in the person who has just been exposed to HIV.

Do I need PEP?

Although guidelines are available for assessment of risk in reality it can be very difficult to come to a clear conclusion of risk in many patients. This is where a proper understanding of individual circumstances of exposure are taken into account and a decision is made about the quantum of risk.

PEP medications are recommended for those whose exposure puts them at a substantial risk of acquiring HIV. The persons who are most at risk are men who have sex with men and hetrosexual persons who have had unprotected sex with people from areas of high HIV prevelance.

How can I be sure that I DO NOT need PEP?

Given that commencement of PEP within stipulated period is essential its important that a proper assessment is done so as not to miss the opportunity for taking PEP.

If you are unsure about the level of risk of acquiring HIV and your suitability of PEP, we recommend speaking to your sexual health clinician.

When should I start PEP?

It is best to start PEP within 24 hours after a recent possible exposure to HIV, but the sooner you start PEP the better as every hour counts. PEP should not be started more than 72 hours after exposure.

How does PEP work?

When someone gets exposed to HIV, the virus needs some time to reach its target cells where it multiplies and infection becomes permanent. It is believed to take upto 3 days from the exposure to the virus and infection becoming permanent in the person. PEP aims to stop the virus from multiplying in this phase and thus aborting the infection.

Where can I get PEP?

You can get PEP from us, your local sexual health clinic and some A&E departments.

What medications does PEP consist of?

  1. Truvada
    • Called ‘PrEP’ (Pre-Exposure Prophylaxis) when taken without Raltegravir
    • Combination of Tenofovir and Emtricitabine (FTC)
  2. Raltegravir

In some circumstances other combinations of HIV drugs may need to be used when there is concern about potential side effects or resistance of the virus in the source person.

How long do I take PEP for?

PEP is taken for 28 days, with 3 tablets taken daily.

Some sexual health clinics have a policy of supplying a 5 days starter pack, followed by a further 23 days worth of supply. This is based on availability.

How do I take PEP?

  • Truvada 1 tablet, once daily for 28 days (ideally taken after food)
  • Raltigraver 400mg 1 tablet, twice daily for 28 days (can be taken independently of food)

What are the side effects of PEP?

  • Sickness
  • Upset stomach
  • Sometimes there can be reversible changes to the kidneys

Can I drink alcohol with PEP?

Yes you can.

Can I take PEP during pregnancy?

Yes you can.

Can I take PEP with other medications?

Current use of PEP medications can be safely taken with most commonly used medications for other purposes. Doctors will however ensure that there is no substantial interaction with these drugs before starting.

What is required before taking PEP?

  • A clinical assessment
  • Your sexual contact was within 72 hours
  • A baseline HIV test to confirm that you do not already have HIV before taking PEP medications.

What happens if I miss a dose or two of PEP?

It is important to take the medications on time without missing any dose for maximum effectiveness. If you miss a dose for a day you should still carry on taking the remaining tablets. However, if you miss 2 consecutive doses PEP may fail to work.

Do I have to finish my PEP course?

It is highly recommended that you finish your full 28 day course of PEP. Your doctor might recommend you to stop the course early if you are experiencing severe side effects or the status of the source person has been confirmed to be HIV negative (or has an undetectable viral load).

What happens if I miss a dose or two of PEP?

It is important to take the medications on time without missing any dose for maximum effectiveness. If you miss a dose for a day you should still carry on taking the remaining tablets. However, if you miss 2 consecutive doses PEP may fail to work.

How effective is PEP?

Effectiveness of PEP is very hard to judge as in most instances the HIV status of the source patient is unknown.

The support for use of PEP in prevention in the prevention of HIV stems from the historical data and expert opinions. The evidence of higher order is obtained by conducting randomised controlled trials and the very nature of PEP makes it ethically difficult for the conduct of such a trial.

PEP has been widely used over the last 20 years and has proven to be a very safe intervention. The older drugs used with PEP used to have troublesome gastrointestinal side effects which fortunately is not an issue with currently used medications in PEP. As such, the relative safety of currently used medications in PEP far outweighs risk and impact from getting HIV.

Is generic PEP any less effective?

As long as the medications are genuine, generic drugs are expected to be just as effective as branded PEP. Generic HIV medications are used widely in treatment of HIV positive patients throughout the world and no concerns have been reported of inferior results from generic drugs compared to branded ones.

How long do I have to wait before having sex again?

It is highly unlikely that someone on effective PEP will pass on the virus to their partners while they are on it. However, prudence demands that someone who has been deemed to be at a substantial risk of acquiring HIV necessitating commencement of PEP avoids unprotected sexual contact with their partner until a negative HIV test after completing PEP.

When should I get a follow up HIV test?

BHIVA guidelines recommend an HIV test 28 days after possible exposure. This is to be repeated at 90 days after possible exposure – this is to categorically exclude the infection.

You can, of course, opt for a HIV-1 Qual PCR test for the early detection and intervention of HIV. However, this will have to be followed by a 4th Generation HIV test at 28 and/or 90 days.

I have some more questions...

We understand that being in a situation where you might need PEP can be overwhelming and stressful. We would highly recommend a consultation with one of our doctors to discuss your questions in person.

If you are experiencing symptoms of HIV-AIDS, we would recommend getting tested and begin treatment without delay.

Understanding HIV-AIDS




Page reviewed by Dr. Manoj Malu (Clinical Director)

Last reviewed date: 21 April 2020
Next review due: 21 April 2023

Whilst this content is written and reviewed by sexual health specialists, it is for general guidance only. It is not intended to replace the advice of your clinician.

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