Febuxostat differs from allopurinol in gout prophylaxis because it:

• A Is a purine analogue that is incorporated into xanthine oxidase, causing irreversible enzyme inhibition
• B Acts as a uricosuric agent, increasing renal uric acid excretion rather than inhibiting synthesis
• C Selectively inhibits the reduced (dehydrogenase) form of xanthine oxidoreductase without affecting the oxidase form
• D Is a non-purine, non-competitive xanthine oxidase inhibitor that does not require renal dose adjustment and does not interfere with purine metabolism ✓

Explanation

Febuxostat is a non-purine selective inhibitor of xanthine oxidase (both reduced and oxidised forms). Unlike allopurinol (a purine analogue that is itself metabolised by xanthine oxidase to oxypurinol), febuxostat does not affect purine or pyrimidine metabolism. It is metabolised hepatically and does not require renal dose adjustment — a major advantage over allopurinol in patients with renal impairment. Probenecid and benzbromarone are uricosurics.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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