Delayed elimination in humans after ingestion of colchicine: Two fatal cases of colchicine poisoning

Colchicine has been widely used in the treatment of acute gout over the years, but it has a narrow therapeutic index, and overdose can be life threatening. A method using ultra‐high‐performance liquid chromatography–tandem mass spectrometry system was applied in two fatal cases of colchicine poisoning in this study to the determination of colchicine in blood. In case 1, a 19‐year‐old man suffered from depression and ingested 160 colchicine tablets (each 0.5 mg). The concentration of colchicine in his blood samples showed a fluctuating trend and kept above the therapeutic steady‐state concentration for 5 days. In case 2, a 70‐year‐old female patient with a history of gout and chronic colchicine intake ingested five times the usual dose of colchicine (5 mg) and died after 12 days of medical care, with 5 ng/mL of colchicine in her blood sample. Our findings suggest that the delayed elimination and accumulation in humans after colchicine overdose could keep the concentration of colchicine maintaining above the therapeutic steady‐state concentration for many days before dying, probably along with a fluctuating trend.