Febuxostat differs from allopurinol in the treatment of chronic hyperuricaemia primarily because it:

• A Is a purine analogue that competitively inhibits xanthine oxidase
• B Inhibits urate transporters URAT1 and OAT4 in the proximal tubule, increasing urate excretion
• C Activates uricase to convert urate to allantoin, which is more soluble
• D Is a non-purine, non-competitive inhibitor of both oxidised and reduced forms of xanthine oxidase, with no need for dose adjustment in mild-to-moderate renal impairment ✓

Explanation

Febuxostat is a non-purine, selective xanthine oxidase inhibitor that inhibits both the oxidised (Mo6+) and reduced (Mo4+) forms of the enzyme by a non-competitive mechanism; unlike allopurinol (a purine analogue requiring conversion to oxypurinol by xanthine oxidase), febuxostat's metabolism is hepatic and does not require renal adjustment in mild-to-moderate CKD, making it preferred when allopurinol is not tolerated or is ineffective. Uricosuric action (URAT1/OAT4 inhibition) belongs to probenecid and lesinurad. Uricase activation is the mechanism of rasburicase/pegloticase.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.