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Allopurinol lowers the amount of uric acid produced in the body.

It's also known by the brand names Alopur, Tipuric and Zyloric.

You can only get allopurinol on prescription. It comes as tablets.

Allopurinol is for adults. It is very rarely given to children.

Uses for allopurinol

Allopurinol is used to treat gout and kidney stones.

You might also have to take allopurinol if you are getting cancer treatment.

Making lifestyle changes, alongside taking this medicine, might help to stop or reduce further gout attacks.

Find out more from Arthritis Ireland about living with gout.

Get emergency help

You might have to get emergency help or go to an emergency department (ED) if you:

  • take too many tablets
  • have a serious allergic reaction

If you take too much

Urgent advice: Go to your ED or phone your GP if:

  • you take too many tablets

Bring the allopurinol packet or leaflet with you, plus any remaining medicine.

Serious allergic reaction

Serious allergic reactions (anaphylaxis) to allopurinol are very rare.

Urgent advice: Phone a GP straight away if:

  • you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
  • you're wheezing
  • you have tightness in the chest or throat
  • you have trouble breathing or talking
  • your mouth, face, lips, tongue or throat start swelling
  • you have a high temperature of 38 degrees Celsius or higher along with a headache, aching muscles and generally feel unwell
  • you have bleeding in the lips, eyes, mouth, nose or genitals
  • you have ulcers of the mouth, throat, nose, genitals and conjunctivitis

Do not take any more tablets unless your doctor tells you to.

Stomach pain or bruising

Urgent advice: See your GP as soon as possible if you:

  • have severe stomach pain – this may suggest an inflamed liver
  • are bruising more easily than usual, a sore throat or other signs of an infection

Check if you can take allopurinol

Get advice from your GP before you take allopurinol if you:

  • are pregnant or breastfeeding
  • have an existing health problem
  • are taking other medicines, including herbal medicines, vitamins or supplements
  • are of Han Chinese, African or Indian origin

Allopurinol if you are pregnant

If you are pregnant, think you might be pregnant or are trying to have a baby, talk to your GP or pharmacist before taking allopurinol.

Allopurinol is not usually recommended during pregnancy. There is not enough evidence to say that it's safe.

Breastfeeding and allopurinol

Allopurinol passes into breast milk.

Talk to your GP or pharmacist before taking allopurinol if you are breastfeeding.

If you have an existing health problem

Allopurinol is not suitable for some people.

Check with your doctor before starting to take allopurinol if:

  • you have ever had an allergic reaction to allopurinol or any other medicines
  • you're having liver, thyroid or kidney problems
  • are currently experiencing an acute attack of gout


Your doctor will usually start you on a low dose of allopurinol.

You'll have regular blood tests to monitor your uric acid levels.

Your doctor may increase or decrease your dose depending on the results of your blood tests.

When to take allopurinol

Always take allopurinol exactly as your doctor has told you. Check with your GP, pharmacist or nurse if you are not sure.

Usually, you'll take allopurinol once a day after a meal.

Swallow the tablets with a little water. Drink plenty of fluids while you are taking allopurinol.

Contact your GP if you feel an attack of gout coming on.

Keep taking your allopurinol even when you no longer have symptoms.

How long it takes to work

Usually it takes several months to feel the full benefits of allopurinol.

When allopurinol is taken regularly, it can lower the number of gout attacks and help prevent damage to the joints.

How long you need to take allopurinol

Treatment with allopurinol is usually lifelong. If you stop taking it your symptoms are likely to come back.

Do not stop taking allopurinol unless your GP tells you to.

You should talk to your GP first if you want to stop taking allopurinol.

If you forget to take it

If you forget to take your dose, take it as soon as you remember.

Skip the forgotten dose if you forget to take it and it’s almost time for your next dose. Never take a double dose to make up for a missed dose.

Use an alarm to help remind you to take your doses. Ask your pharmacist for advice if you forget doses often.

Side effects of allopurinol

Allopurinol can cause side effects, although not everyone gets them.

The most common side effect of allopurinol is a skin rash.

See the patient information leaflet that comes with your medicine for a full list of side effects. 

Non-urgent advice: Find your patient information leaflet

Your patient information leaflet is the leaflet that comes with your medicine. You can find a digital version of the leaflet online.

Report side effects

You can report any suspected side effects to the the Health Products Regulatory Authority (HPRA): report an issue -

If you get a skin rash

Stop taking allopurinol and talk to your GP if you get a skin rash.

You might be able to get a lower dose or have to stop taking allopurinol. It will depend on if the rash is mild or returns.

Driving or cycling and allopurinol

Allopurinol may make some people drowsy or have problems with their coordination.

Do not drive, cycle or operate machinery if these symptoms affect you.

Fact check

This content was fact checked by a pharmacist, a GP, the National Medication Safety Programme (Safermeds) and the Health Products Regulatory Authority (HPRA).

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This project has received funding from the Government of Ireland’s Sláintecare Integration Fund 2019 under Grant Agreement Number 123.

Page last reviewed: 24 September 2021
Next review due: 24 September 2024