Which drug is a xanthine oxidase inhibitor used for chronic gout management?

• A. Allopurinol
• B. Colchicine
• C. Indomethacin
• D. Pegloticase

Answer: (A)

The key idea is lowering uric acid production to prevent chronic gout flares. A xanthine oxidase inhibitor accomplishes this by blocking the enzyme that converts hypoxanthine to xanthine and xanthine to uric acid, thereby reducing serum urate levels. Allopurinol is the classic agent in this class and is used for long-term urate lowering and tophi management in chronic gout.

Colchicine works by inhibiting neutrophil activity to reduce inflammation during flares, not by lowering uric acid. Indomethacin is an NSAID that provides symptomatic relief for acute gout. Pegloticase breaks down uric acid to allantoin via uricase, which is used in refractory cases and is not a xanthine oxidase inhibitor.