Allopurinol is used to treat gout and kidney stones. It may also be prescribed during some types of cancer treatment that can cause a build-up of uric acid. It comes as 100mg and 300mg tablets and is only available on prescription.

WHO CAN AND CANNOT TAKE ALLOPURINOL?

Allopurinol can be taken by adults and sometimes children. It is not suitable for certain people, for instance:

• Patients with allergies to allopurinol or similar medications

• Those of Han Chinese, Thai or Korean origin

• Patients who have liver or kidneys problems

• Those who currently have an attack of gout

• Patients with thyroid problems.

HOW AND WHEN TO TAKE IT

The usual dose of allopurinol is 100mg to 300mg a day. Do regular blood tests to monitor uric acid levels. If uric acid levels do not come down far enough, you may need to increase the dose (up to 900mg daily in severe cases). Monitor patients with kidney or liver disease closely. Allopurinol should be taken ideally after food, once a day, but this might need to be split into two doses for those on a high dose. Take the doses at the same time of day each day.

WHAT IF I FORGET TO TAKE IT?

If patients take allopurinol:

• Once a day – take the missed dose as soon as you remember. If you do not remember until the following day, skip the missed dose

• Twice or more a day – if you do not remember until your next dose is due, skip the missed dose and take the dose that is due.

Patients should never take a double dose to make up for a missed dose.

CAUTIONS WITH OTHER MEDICINES

Some medicines and allopurinol can interfere with each other and increase the chances of side effects.

Medicines that may interact with allopurinol include:

• Aspirin or anticoagulants, such as warfarin

• Antibiotics

• Immunosuppressants

• Diuretics such as furosemide or ACE inhibitors

• Leave a three-hour gap between the aluminium hydroxide (found in some antacids) and the allopurinol dose.

KEY FACTS

• Allopurinol reduces the amount of uric acid made by the cells. This reduces symptoms such as swollen and painful joints

• It may take several months before patients feel the full benefit of allopurinol

• During the first few months of treatment, as allopurinol starts to work, patients may get more gout attacks. However, non-steroidal anti-inflammatory drugs (NSAIDs) or colchicine will help with this

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

• Usually, a patient will start allopurinol after an acute attack of gout has completely settled.