Febuxostat is used for hyperuricemia in gout. Compared to allopurinol, what is its key pharmacological advantage, and which patients benefit most from this property?

• A Febuxostat is a competitive inhibitor of xanthine oxidase, allowing physiological uric acid production to continue
• B Febuxostat is a non-purine selective inhibitor of both oxidized and reduced forms of xanthine oxidase, with no renal dose adjustment needed in mild-moderate CKD ✓
• C Febuxostat inhibits URAT1 transporter in the proximal tubule, increasing renal uric acid excretion
• D Febuxostat blocks purine de novo synthesis, reducing total purine load

Explanation

Allopurinol and its active metabolite oxypurinol are purine analogues that inhibit xanthine oxidase competitively (allopurinol) and non-competitively (oxypurinol). Febuxostat is a non-purine selective inhibitor of xanthine oxidase in both its oxidized and reduced forms, meaning it does not affect other enzymes involved in purine or pyrimidine metabolism. Critically, febuxostat is predominantly metabolised hepatically (glucuronidation) and does not require dose adjustment in mild-to-moderate CKD (unlike allopurinol, which requires dose reduction due to renal oxypurinol accumulation). Option C describes lesinurad/probenecid (uricosurics).

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

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Written and medically reviewed by the StethoPrep medical team.