Targeting the NLRP3 Inflammasome with Colchicine in COVID-19: Therapeutic Evidence and Future Implications for Influenza

Coronavirus disease 2019 (COVID-19) and influenza share key pathogenic mechanisms, including viral invasion, dysregulated innate immune activation, and the development of severe systemic complications. A central mediator of disease progression in both infections is the hyperactivation of the NLRP3 inflammasome, which drives excessive production of pro-inflammatory cytokines, immunothrombosis, multiorgan injury, and increased mortality. Colchicine possesses a unique pharmacokinetic property of preferential accumulation within myeloid cells, where sufficiently high intracellular concentrations inhibit NLRP3 inflammasome activation. This mechanism provides a biological rationale for preventing the cytokine storm and its downstream consequences when colchicine is administered early during infection. Available pharmacokinetic, toxicological, and clinical evidence suggests that loading doses of colchicine up to approximately 0.05 mg/kg body weight can be administered safely in appropriately selected patients, provided that clinically significant drug–drug interactions and hepatic or renal impairment are carefully excluded. The widely accepted belief that total doses of 7–7.5 mg are inherently lethal appears to reflect historical cases complicated by drug interactions and/or hepatic or renal impairment, rather than toxicity attributable to colchicine dose alone. These observations support reconsideration of current guideline recommendations regarding colchicine dosing. In particular, cumulative doses below 0.1 mg/kg appear to be consistently safe, whereas doses between 0.1 and 0.2 mg/kg are associated with only a low risk of toxicity and rarely with severe intoxication. Reassessment of colchicine dosing strategies may therefore be warranted to optimize NLRP3 inflammasome inhibition and improve outcomes in patients with COVID-19 and influenza.