Adults: Allopurinol should be introduced at low dosage e.g. 100mg/day to reduce the risk of adverse reactions and increased only if the serum urate response is unsatisfactory. Extra caution should be exercised if renal function is poor. The following dosage schedules are suggested: 100 to 200 mg daily in mild conditions, 300 to 600 mg daily in moderately severe conditions, 700 to 900 mg daily in severe conditions.
Children: Children under 15 years: 10 to 20 mg/kg body weight/day up to a maximum of 400 mg daily. Use in children is rarely indicated, except in malignant conditions (especially leukaemia) and certain enzyme disorders such as Lesch-Nyhan syndrome.
Elderly: In the absence of specific data, the lowest dosage which produces satisfactory urate reduction should be used.
Dosage in renal impairment: In severe renal insufficiency, it may be advisable to use less than 100 mg per day or to use single doses of 100mg at longer intervals than one day.