Health risks and side effects of PrEP
To decide if PrEP is right for you, there are some health risks and side effects to think about.
Whether you’re likely to be affected by these risks will depend on your health and family history. This is why when you start PrEP, you’ll be asked some questions about your health. This helps the clinicians check that it’s safe to prescribe.
If you order from SH:24, we’ll also ask you to take some regular tests so we can make sure you’re staying healthy.
Side effects
PrEP affects each person differently. Most people will not get any side effects. But you might experience some, especially when you first start PrEP.
These side effects will not cause any problems with your health, but they can be hard to live with.
If you’re worried about any side effects when taking PrEP, keep a record of when they happen. If they do not go away after your first month of PrEP, talk to your clinic for advice.
The NHS website has advice for managing PrEP side effects.
Common side effects
Common side effects in the first few weeks of taking PrEP include:
diarrhoea
being sick (vomiting)
feeling sick (nausea),
dizziness
headache
rash
feeling weak
difficulty sleeping (insomnia)
PrEP is a very safe medication to take, and when taken correctly it’s extremely effective at stopping you acquiring HIV. Any of these side effects that you notice should end after the first few weeks of being on PrEP.
Health risks
Kidney function
PrEP can sometimes affect how well your kidneys work. This is why you’ll take tests for your kidney function before you start PrEP and regularly while you are on it.
The risk of kidney damage on PrEP is very low. In an Australian study, following 5,973 people on PrEP over 3 years, they found kidney issues in 0.7% of users taking PrEP daily. It’s more likely to affect your kidneys if you’re over 50 or you have pre-existing kidney problems. And the risk stops once you stop taking PrEP.
If you get PrEP from SH:24, we’ll help you to regularly check your kidney function with at-home tests.
Bone density
PrEP can slightly reduce the strength and density of your bones. Typically people see a 1-2% loss of bone density in their first year on PrEP. This is not permanent, your bones return to normal once you stop taking PrEP, and this does not increase your risk of fractures while you are using PrEP.
This change in bone density rarely causes problems. If you have osteoporosis, a history of bone fractures or if you have problems with your bones, tell your PrEP provider before you start the medication.
Hepatitis B
PrEP has an effect on the hepatitis B virus. This can cause problems for people who have hepatitis B, as when you stop taking PrEP you can experience a flare in hepatitis symptoms and possible liver problems. Do not use on-demand dosing of PrEP if you have hepatitis B or if you’ve had it in the past.
You will be offered a test for hepatitis B before you are prescribed PrEP. Being certain of your hepatitis B status means you can reduce the risks and understand which dosing regime is best for you.
Allergic reaction
As with any medication, food or drink, there’s a chance that some people will be allergic to the ingredients in PrEP. It's very rare, but this can cause a serious allergic reaction called anaphylaxis.
If you experience any or all of the following call 999 immediately:
your lips or mouth become swollen or tingly
your throat feels tight
you develop a rash
you feel drowsy or dizzy
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