Toxicological management of chlorophacinone poisoning

A 33-year-old man was admitted 8 hours after voluntary ingestion of 1875 mg of chlorophacinone (C'Operat(R) 750 mt). The examination revealed excitati on and nausea, with a normal prothrombin index (PI). Comprehensive testing for abused and therapeutic drugs in blood confirmed chlorophacinone (maximu m plasma level: 27.6 mg/L), an antivitamin K (AVK) rodenticide. In a search for easy toxicological management of chlorophacinone poisoning treated by phytomenadione and a cytochrome P450 inducer (phenobarbital), PI and chloro phacinone plasma levels were monitored concomitantly during 17 days. A simp le HPLC procedure for the determination of chlorophacinone in human plasma is reported for that purpose. Under phenobarbital 200 mg/day, chlorophacino ne exhibited an apparent elimination half-life (3.27 days) shorter than in previously reported cases. If PI is useful for planning phytomenadione trea tment and used for therapeutic monitoring of AVK, the chlorophacinone conce ntrations follow-up may provide a better estimation of the duration of hosp italisation. Chlorophacinone accumulation in target cells or existence of a n unidentified metabolite may explain persistence of the hypocoagulability syndrome at low plasmatic concentrations of chlorophacinone. This case illu strates how toxicological management may facilitate toxicokinetics and ther apeutic data acquisition.