Colchicine is used for acute gout flares. Its mechanism differs from NSAIDs because colchicine specifically:
- A Inhibits COX-2 in synovial tissue reducing prostaglandin-mediated inflammation
- B Binds beta-tubulin, disrupting microtubule polymerization and impairing neutrophil chemotaxis and NLRP3 inflammasome activation ✓
- C Blocks IL-1 receptor signaling downstream of NLRP3 inflammasome activation
- D Promotes solubilization of monosodium urate crystals within the joint space
Correct answer: B. Binds beta-tubulin, disrupting microtubule polymerization and impairing neutrophil chemotaxis and NLRP3 inflammasome activation
Explanation
Colchicine binds to the beta subunit of tubulin as a heterodimer, preventing microtubule polymerization. This inhibits neutrophil migration (chemotaxis requires intact microtubule cytoskeleton) and reduces the assembly of the NLRP3 inflammasome (which depends on microtubule transport of its components). The NLRP3 inflammasome processes IL-1beta and IL-18, which are central mediators of crystal-induced inflammation. Colchicine does not dissolve urate crystals or inhibit COX.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.