Allopürinol

Prevent attacks of gouty arthritis and nephropathy
Prevent cancer chemotherapy-induced hyperuricemia (inhibits xanthine oxidase, thus preventing conversion of hypoxanthine to uric acid)
Children ≤ 10 yr: 10 mg/kg/24 hr in 2–3 divided doses.
Children > 10 yr and adults: 200–600 mg/24 hr in 2–3 divided doses.

Gout,chemotherapy-induced hyperuricemia  600–800 mg/24 hr in 2–3 divided doses starting 1–2 days before chemotherapy and continuing for 3 days

Renal impairment:
CrCl 10–50:reduce dose to 50%.
CrCl < 10:reduce dose to 30% of suggested.