Fatal intoxication because of trihexyphenidyl

Trihexyphenidyl (THP) is an anticholinergic agent with forensic toxicological interest. We present a case of a 59-year-old woman with a history of paranoid disorder, who was found dead in the house where she lived alone. The autopsy findings revealed no marked pathological changes. Toxicological analysis based on gas chromatography-mass spectrometry (GC-MS) analysis revealed THP and its major metabolite (hydroxy-THP) in blood and urine, with THP concentrations of 0.053 and 0.560 mg/L, respectively. The blood and urine ethanol concentrations were low 0.096 and 0.100 g/L, respectively. Based on these results, we determined the cause of death to be THP poisoning. It is suggested that rare case of death associated with THP overdosage should be taken in conjunction with central nervous system depressants (benzodiazepines, ethanol) and/or with other pathological disorders. Thus, our case could not be supportive for this allegation.