Colchicine is used acutely for gout. Its primary mechanism is best described as:

• A Inhibition of xanthine oxidase reducing uric acid production
• B Blockade of URAT1 in the proximal tubule increasing uric acid excretion
• C Competitive inhibition of prostaglandin H synthase
• D Binding to tubulin and preventing its polymerization, thereby inhibiting neutrophil migration and phagocytosis of urate crystals ✓

Explanation

Colchicine binds to tubulin dimers and prevents microtubule polymerization. This impairs neutrophil motility, degranulation, and phagocytosis of monosodium urate crystals in the synovial fluid, reducing the inflammatory response characteristic of acute gout. It does not lower serum uric acid levels. Allopurinol inhibits xanthine oxidase; probenecid blocks URAT1; NSAIDs inhibit prostaglandin synthesis.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.