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 Is the conflicting information I am receiving due to outdated data or current data?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. Josh Peasegood

    Hi Honey, using a 4th gen antigen/antibody test will be conclusive from 6 weeks after the last dose of PEP. If you are using a 3rd generation antibody test you will need to wait 12 weeks before your result is conclusive.

    HIV PCR tests are not used to confirm an HIV status as they are prone to false positives due to other infections.

    More information about testing can be found here: https://i-base.info/qa/factsheets/hiv-transmission-and-testing

  2. Honey

    Sir,mera exposure hua tha 24 december ko or me ak doctor ko mila unhone mujhe pep diya 1 january ko uske baad me continue pep liya fr uske baad 12 tarik ko mujhe ser me dard hua or dane pet per nikle ,maine vo pep khtm ke 35 days ke baad p24 test kraya jo negative aya uske baad 45 days ke p24 kraya vo bhi negative ,uske baad 52 din pe RNA PCR test kraya vo bhi negayive aya or aab 70 days per p24 kraya vo bhi negative aya ,,,lakin aab sir me dard nhi hota lakin panis pe red dane h or pet me hlka dard h ,,,kya mujhe hiv h please help me

  3. Josh Peasegood

    Hi Alex, there is no risk of HIV transmission from this event. You do not need to be concerned about HIV.

    Please see here for more information about transmission: https://i-base.info/qa/factsheets/hiv-transmission-and-testing

  4. Alex


    Hope you are well.

    I was recently involved with a girl (white british). While engaged in foreplay (fingering) she began to sleep. Once it realised, I made sure she was ok and went to wash my hand. When turning on the tap the small bit of water splashed on my exposed penis head. I proceeded to wash my hand quickly then wash the tip of my penis.

    I believe logically the risk of HIV is very small. But I have recently been informed that she does not usually use protection and sleeps with a man (also british) who works in Somalia.

    I know I am being paranoid, but is there any real risk? She is a health worker and gets tested but their last encounter was a month ago so obviously that will not show up on any tests.

    Apologies for the ramble.


  5. Josh Peasegood

    Hi Paulo, orange juice will not interfere with the efficacy of your meds. You can drink as much orange juice as you want without it impacting your treatment.

  6. Paulo

    Hello, I have a doubt.

    I took a full bottle of orange juice 3h30 after taking my first dose of PEP. Does fruit juice interfere with the efficiency of the meds?

    Thank you so much for taking your time to take all these doubts, it feels good to not feel so unseen sometimes.


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