Q and A


Does PEP have side effects?


I am confused with PEP treatment, specifically about the side effects.

From sexual health charities I hear that PEP treatment can cause occasional side effects which may or may not go over the 28 days treatment. Another one (THT) says that the side effects are extreme and about 1 in 5 people on PEP stop taking it as a result.

The sexual health nurse said that side effects on PEP are very common and are severe.

I’ve heard from 3 people who have had PEP and they said that they didn’t get any side effects.

What’s the official line on PEP and side effects? I thought that PEP usually uses recommended triple therapy, using drugs that are well tolerated. Is the conflicting information I am receiving due to outdated data or current data?

Thank you for any clarity you provide.


All meds have some risk of side effects, but for PEP this risk is usually low. If side effects do occur, they are usually mild.

This depends on the meds used in the PEP combination.

In the UK in 2018, the PEP combination is usually raltegravir plus a combined pill with tenofovir DF/emtricitabine, which generally causes very few side effects, if any.

Even general side effects like nausea, diarrhoea and tiredness are not experienced by most people.

If mild side effects occur, they usually get easier after the first week or two as your body adjusts.

PEP that contains a drug called efavirenz is not recommended in the UK, though is used in some countries where there is less choice for HIV drugs. Efavirenz has a higher risk of side effects including mood changes and vivid dreams.

Discontinuation rates for PEP are often not very good. Studies of health workers who are exposed with a needle-stick injury report many people stop before the full month of treatment.

Note: This answer was updated in February 2018 from a question first posted online in June 2009.


  1. Lisa Thorley

    Hi Afshin,

    The meds that you’re taking aren’t known to cause yellow eyes. Those that may cause issues with yellowing of the eyes are discussed here: http://i-base.info/guides/side/bilirubin-and-jaundice

  2. Afshin

    My pep tablet is emtricitabine / tenofovir and isentress .600mg .
    I just seen in this page complain of yellow eyes
    Is it possible my pep do this side effects ? I’m really worried please reply me soon as possible

  3. Roy Trevelion

    Hi Immy,
    It’s a good idea to have these symtoms checked out by your doctor. If they are side effects you can ask to change to other PEP meds. If your blood pressure is high you should talk to the doctor about treatment for it.

  4. Immy

    Hi am immy I have been on PEP now 2 1/2 weeks at first I could feel dezinence and other effects but now I fill the abdomen full every time have only prone position to rest too can’t lie on my back nor abdomen,ever tired ,mood changes and now worrying bp is in hypotetion what could be the problem

  5. Roy Trevelion

    Hi Josephine,
    An increase in bilirubin is a common side effect of atazanavir. This drug caould be in your PEP. And it can cause yellowing of the eyes. Small increases in bilirubin are not causing any damage to your body. But you could ask the doctor if there is another drug you can change to. However, after your course of PEP this side effect should go away.

  6. Josephine

    its now one week when am taking pep but my eyes are becoming yellow…. What can I do to prevent it


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