Allopurinol: Price, Dosage & Where to Buy

Allopurinol is a xanthine oxidase inhibitor used mainly to manage gout by reducing uric acid production. It is also used for raised uric acid linked with cancer treatment and for some recurrent calcium oxalate kidney stones. Allopurinol requires a prescription in the United Kingdom and has been available as a generic medicine since 1986-10-24.

Allopurinol belongs to a class of medicines called xanthine oxidase inhibitors. Xanthine oxidase is an enzyme involved in the body's production of uric acid. By inhibiting this enzyme, allopurinol reduces the formation of uric acid and its active metabolite also contributes to this effect.

Lower uric acid levels can reduce the build-up of urate crystals in joints and tissues, helping manage gout over time. The same action can help control uric acid increases associated with cancer treatment and may reduce the uric acid contribution to some recurrent calcium oxalate stones. Changing uric acid levels at the beginning of treatment can temporarily trigger gout flares as urate deposits are mobilised.

Allopurinol is used to manage adults with signs and symptoms of primary or secondary gout, including acute attacks, tophi, joint destruction, uric acid stones and uric acid-related kidney disease. It is also used in adults and children with leukaemia, lymphoma or solid tumour cancers who are receiving treatment that can raise uric acid in the blood and urine.

In adults, it can be used for recurrent calcium oxalate stones when daily uric acid excretion remains high despite lifestyle changes such as reducing dietary sodium, non-dairy animal protein, oxalate-rich foods and refined sugars, while increasing oral fluids, fruit and vegetables. It is not recommended for people who have raised uric acid without symptoms.

The label lists 100 mg, 200 mg and 300 mg oral tablets, and a 500 mg/25 mL intravenous powder for solution. The usual starting dose is 100 mg orally daily for gout in patients with normal kidney function. The label lists 50 mg orally daily as the initial dose for gout when kidney function is impaired.

The label lists weekly increments of 100 mg for gout until the serum uric acid target is reached, with a maximum of 800 mg daily. The label lists 300 mg to 800 mg orally daily for adults with cancer-therapy-related hyperuricaemia. The label lists 100 mg/m2 orally every 8 hours to 12 hours for paediatric patients in that setting, with a maximum of 800 mg/day.

The label lists 200 mg to 300 mg orally daily as the initial dosage for recurrent calcium oxalate stones with normal kidney function. Doses above 300 mg should be given in divided doses. The label states that a missed dose does not require doubling at the next scheduled time.

Store allopurinol tablets at 15°-30°C and protect them from moisture, as directed on the label. Keep the medicine in its original container with the child-resistant closure and away from children. Do not use damaged or deteriorated tablets; ask a pharmacist how to dispose of unwanted medicine.

A missed dose does not mean that the next dose should be doubled. The label states that doubling is unnecessary at the next scheduled time. Follow the prescribed schedule and ask a pharmacist or doctor for individual advice, particularly when allopurinol is being used for gout, cancer-therapy-related hyperuricaemia or recurrent stones.

Allopurinol may cause fetal harm, based on findings in animals, and allopurinol and oxypurinol cross the placenta. Limited published human data do not show a clear pattern or increase in adverse developmental outcomes, but major congenital malformations have been reported. Discuss pregnancy or planned pregnancy with a doctor.

Allopurinol and oxypurinol are present in human milk. The label advises women not to breastfeed during treatment and for one week after the last dose.