Colchicine's primary mechanism for preventing gouty arthritis attacks involves:

• A Inhibition of xanthine oxidase, reducing uric acid synthesis
• B Binding to tubulin dimers, disrupting microtubule polymerisation and neutrophil migration ✓
• C Blockade of URAT1 transporter in the proximal tubule to enhance uric acid excretion
• D Inhibition of NLRP3 inflammasome assembly in macrophages via PYRIN binding

Explanation

Colchicine binds to tubulin heterodimers, preventing their polymerisation into microtubules. This disrupts the cytoskeletal architecture required for neutrophil chemotaxis, degranulation, and superoxide production in response to MSU crystals. By arresting neutrophil migration into the joint, colchicine reduces the inflammatory cascade without affecting uric acid levels. URAT1 blockade is the mechanism of lesinurad (uricosuric). NLRP3 inflammasome inhibition is emerging but not colchicine's primary mechanism.

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

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

Written and medically reviewed by the StethoPrep medical team.