Allopurinol
NHS information about the medicine allopurinol, including what it's used for, who can take it, how to take it and side effects.
What allopurinol is for
Allopurinol helps reduce the amount of uric acid in your body. Uric acid is a waste product that can cause problems if levels get too high.
It can be used to:
- prevent gout attacks
- prevent some types of kidney stones
- prevent problems caused by uric acid build-up during some types of cancer treatment
How to take allopurinol
Allopurinol comes as tablets or as a liquid (oral suspension) that you swallow.
You usually need to take it once a day, but if you're taking a higher dose you may need to take it up to 3 times a day. Your doctor will explain your dose to you.
How long you need to take it for depends on why you're taking it. If you're taking it for gout or kidney stones, you may need to take it long term.
When taking allopurinol:
- swallow tablets whole with a glass of water – you can break them in half if your doctor asks you to take a smaller dose
- use the syringe, cup or spoon that comes with the liquid medicine to help you measure the correct dose
- it's best to take allopurinol with food
- drink plenty of fluids to stay hydrated
Always check the packet or leaflet that comes with your medicine. Ask a pharmacist or doctor for advice if you're not sure how to take it or have any problems taking it.
Side effects of allopurinol
Like all medicines, allopurinol can cause side effects, although not everyone gets them.
Possible side effects of allopurinol include:
- a rash or other skin reactions – stop taking allopurinol and speak to your doctor straight away if this happens
- feeling sick (nausea) or being sick (vomiting)
- diarrhoea
Allopurinol will not usually affect your ability to drive, ride a bike or use machinery, but if you feel drowsy, dizzy, sleepy or have problems with your coordination after taking it wait until you no longer have until these side effects.
More about side effects
These are not all the side effects of allopurinol.
For a full list, see the leaflet that comes with your medicine or search for your medicine leaflet on the electronic medicines compendium website.
You can report any side effects you get on the Yellow Card website
Who can and cannot take allopurinol
Most adults can take allopurinol. It's sometimes prescribed for children if they have certain types of cancer.
But allopurinol is not suitable for everyone. For example, it may not be suitable if:
- you've had an allergic reaction or other serious side effect from allopurinol before
- you're of Han Chinese, Thai, Korean, African or Indian ethnic origin – people from these ethnic origins may be more likely to have a severe reaction to allopurinol
- you have thyroid, kidney or liver problems
Before taking allopurinol, tell your doctor if you have any other medical conditions.
Breastfeeding and allopurinol
Speak to your doctor if you're breastfeeding.
Allopurinol can pass into breast milk. It's not known to be harmful for your baby, but there is limited evidence about its effects.
Your doctor will speak to you about the benefits and risks of taking it.
It's rare for breastfed babies to get any side effects from medicine you're taking, but speak to a healthcare professional if you have any concerns about your baby.
Pregnancy and allopurinol
Tell your doctor if you're pregnant or planning a pregnancy while taking allopurinol. They may recommend switching to a different medicine.
Allopurinol is not usually used during pregnancy because it may affect how your baby develops. But a doctor may recommend it if the benefits outweigh the risks.
Taking allopurinol with other medicines, food and drink
There are some medicines, remedies and supplements that may not mix well with allopurinol.
This includes:
- aspirin, or medicines to help prevent blood clots (anticoagulants) such as warfarin
- theophylline, a medicine to treat asthma
- some medicines for high blood pressure or heart problems, such as ACE inhibitors or medicines to make you pee more (diuretics)
- some antibiotics, such as amoxicillin
- some medicines that lower your immune system (immunosuppressants), such as azathioprine
Before taking allopurinol, tell your doctor if you're taking any other medicines, herbal remedies, vitamins or supplements.
Food, drink and alcohol with allopurinol
You can eat and drink as normal while taking allopurinol.
Find out more about your medicine
To find out more about your medicine, you can:
- check the leaflet that comes with it
- search for your medicine leaflet on the electronic medicines compendium website
- speak to a pharmacist or a doctor for advice – if you recently started taking it, you can get help with newly prescribed medicines from a pharmacist as part of the New Medicine Service
