Colchicine prevents gouty arthritis attacks when used prophylactically. Its sub-mechanism for reducing neutrophil recruitment to urate crystal-laden joints involves:
- A Binding beta-tubulin heterodimers and preventing microtubule polymerization, blocking L-selectin-mediated neutrophil rolling and inhibiting NALP3 inflammasome assembly via microtubule disruption ✓
- B Blocking cyclooxygenase-1 in neutrophils reducing prostaglandin-mediated chemotaxis
- C Antagonizing the CXCR2 receptor on neutrophils preventing IL-8-mediated recruitment
- D Inhibiting phospholipase A2 in synoviocytes reducing arachidonic acid availability
Explanation
Colchicine binds to beta-tubulin monomers and prevents their polymerization into microtubules. Microtubule disruption in neutrophils impairs multiple key functions: (1) L-selectin shedding and cell motility required for endothelial rolling and diapedesis; (2) assembly of the NALP3 (NLRP3) inflammasome, which is the sensor for monosodium urate crystals and is required for IL-1beta maturation and release; (3) degranulation and superoxide generation. This is why colchicine is effective in both acute gout and prophylaxis. It does not inhibit COX, CXCR2, or PLA2 directly at therapeutic concentrations.
Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.
High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP
Written and medically reviewed by the StethoPrep medical team.