Known brand names include Zyloprim.
A pill that lowers uric acid to prevent gout attacks, high uric acid during cancer treatment, and some repeat kidney stones. It blocks the enzyme that makes uric acid, and any rash is a reason to stop it, because rare skin reactions can be fatal.
The label does not describe a narrow therapeutic index or direct dosing by measured blood levels of the drug. Dosing targets serum uric acid, not drug levels.
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No specific antidote. Allopurinol and oxypurinol are dialyzable, but whether hemodialysis or peritoneal dialysis helps after an overdose is unknown.
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Doses come from the FDA label. Study tool, not for clinical decisions.
Gout starting doses by eGFR: above 60, no change; above 30 to 60, 50 mg daily; above 15 to 30, 50 mg every other day; 5 to 15, 50 mg twice weekly; below 5, 50 mg once weekly. Increase by 50 mg/day every 2 to 4 weeks to the uric acid target. Cancer therapy: eGFR 10 to 20, 200 mg/day; below 10, 100 mg/day; with dialysis, 100 mg once every 24 hours or 50 mg every 12 hours. Monitor kidney function closely.
No labeled dose change. Monitor liver enzymes periodically in pre-existing liver disease, check them if anorexia, weight loss, or pruritus develop, and stop allopurinol if they are elevated.
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A xanthine oxidase inhibitor and structural analogue of hypoxanthine. It blocks the steps from hypoxanthine to xanthine and from xanthine to uric acid without disrupting purine synthesis. Its active metabolite oxypurinol also inhibits xanthine oxidase and is thought to mediate most of the effect. About 90% is absorbed; half-lives are about 1 to 2 hours for allopurinol and 15 hours for oxypurinol, which the kidneys eliminate.