PrEP stands for pre-exposure prophylaxis. This involves taking medication to prevent HIV infection prior to potential exposure to HIV, unlike post exposure prophylaxis (PEP) which is taken after possible HIV exposure.

PrEP is a combination of two drugs; tenofovir disoproxil fumarate and emtricitabine, which are 2 antiretrovirals that has been used successfully to control and manage HIV for many years. This has been shown to be highly effective in preventing HIV infection if taken correctly.

There are two ways to take PrEP, either daily or ‘on demand’. Daily PrEP is taken one tablet once a day. It needs to be taken same time every day and if PrEP is missed at times of unprotected sex, there is a risk of HIV infection. ‘On demand’ PrEP also known as event based PrEP means taking tablets just before (2 tablets 2 to 24 hours before the sex) and a little while after planned sexual activity (2 further doses in the 48 hours after sex).

PrEP only protects against HIV and it doesn’t protect against other sexually transmitted infections. Therefore PrEP is not a replacement for condoms and should therefore be used jointly with PrEP. 

Who should consider taking PrEP?

PrEP would be of benefit to people who are at higher risk of HIV infection, such as

  • Men who have sex with men
  • Trans men and women
  • People with partners from parts of the world where the rate of HIV infection is much higher
  • People with an HIV positive partner who does not have an undetectable viral load

There are situations where PrEP may be particularly advised such as

  • Men who have sex with men who have had a recent sexually transmitted infection (particularly in the rectum/anus)
  • Those who have used PEP in the past following a sexual risk
  • People who do chemsex (taking drugs to enhance sex)

PrEP and side effects

  • The majority of people taking PrEP do not report any side effects
  • Possible side effects of taking PrEP include nausea, diarrhoea, bloating and headaches. These side effects will usually settle after the first month.
  • PrEP can also affect the kidneys.  This is why monitoring is important. In the small proportion of people taking PrEP who developed reduced kidney function, these changes reversed on stopping PrEP.
  • PrEP can also reduce bone density by 1-5%, causing slight thinning of the bones, however this loss reverses after PrEP is stopped.


  • Speak to a GU specialist if you are interested in PrEP
  • Regular monitoring and follow up as recommended by the GU Specialist
  • Try to take your PrEP pills at a regular time each day
  • Still use condoms to reduce the risk of catching other STIs
  • Tell us if your medical history changed or you started new medications including over the counter, herbal or recreational drugs.


  • Start PrEP without taking an HIV and a kidney test
  • Start or stop PrEP without seeking specialist advice
  • Miss taking any pills

Dr Donia Gamoudi is a Genito-urinary specialist specialising in Sexual Health and HIV. Dr Gamoudi is a specialist in Sex Clinic Malta, offering support and treatment with STIs, HIV and PrEP, as well as blood testing and hormone profiling.