Allopurinol

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.

If you miss a dose of allopurinol

If you forget to take a dose of allopurinol, take it as soon as you remember unless it's nearly time for your next dose.

If it's nearly time for your next dose, skip the dose you missed and take your next dose at the usual time.

Do not take 2 doses to make up for a missed dose.

If you take too much allopurinol

Taking an extra dose of allopurinol is unlikely to cause problems, but it's important to get medical advice if you take too much as it can sometimes be dangerous.

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.

Serious side effects

Allopurinol can sometimes cause serious side effects, although most of them are rare.

Possible serious side effects of allopurinol include:

• a severe allergic reaction (anaphylaxis) – causing symptoms such as a swollen throat or tongue, a raised, itchy rash or difficulty breathing
• a severe skin reaction (Stevens-Johnson syndrome) – causing flu-like symptoms, a rash, blisters and sores
• meningitis – causing symptoms such as a stiff neck, feeling sick, a severe headache and feeling confused
• a serious problem with your white blood cells – causing symptoms such as bruising easily, feeling very tired, a sudden sore throat or a high temperature (you may feel hot, cold or shivery)

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.

Find out more about taking allopurinol during pregnancy on the Bumps (Best Use of Medicines in Pregnancy) website

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.