Colchicine poisoning: case report of two suicides

Colchicine overdose is uncommon but potentially life threatening because of the high toxicity of the drug. Poisoning by colchicine may occur following ingestion of medication used in acute attacks of gout and inflammatory diseases. We describe two cases involving suicide by the ingestion of medications marketed in France. In case 1, only heart blood was taken after body external examination. In case 2 an autopsy was performed and heart blood, urine, gastric contents and bile were taken for toxicological analysis. Colchicine was assayed in biological specimens by an HPLC-DAD method, after extraction by dichloromethane at pH 8, adding prazepam as internal standard (IS). Analyses were performed on a Symetry C-8 column. Mobile phase was a gradient of acetonitrile/pH 3.8 phosphate buffer. Colchicine is eluted at 13.1 min and the method is linear for blood, urine and bile over the range 4-1000 ng/mL. LOQ is 4 ng/mL. The concentrations of colchicine detected are: case 1: heart blood 13 ng/mL; case 2: heart blood 66 ng/mL, urine 500 ng/mL, gastric content 12 ng/mL, bile 5632 ng/mL. Our findings are in the range of lethal concentrations previously described, but there is no correlation with the amount of ingested drug. Even after massive overdose, it could be impossible to detect colchicine in blood, and as there is a widespread enterohepatic recirculation before excretion in bile and feces, bile is the target sample to analyse. We conclude in both cases that the cause of death was suicide with colchicine. It appears very important to perform an autopsy in order to obtain bile, urine, heart blood and femoral blood.