Forensic Determination of Toxication of Strychnos Nuxvomica

Strychnos nux-vomica has been used as a poisonous raw material for the preparation of Chinese medicinal herb for thousands of years in China, it is required that the herb should be specially processed before being put into clinical use. Since its treatment dosage is very close to its toxic dosage, poisoning frequently take place due to misuse, brucine and its derivatives are the principal component responsible for its pharmacodynamic effect and toxicity, strychnine is main component responsible for its toxicity. Both strychnine and brucine are typical antagonists of the glycine receptors on postsynatic membrane. Its toxic effects are mainly to cause central excitation. Because of its strong toxicity, narrow safety range and cumulative effect, the use of the drug in the clinical practice tends to cause poisoning, and poisoning of the drug is associated with the large dosage, and/or the long time use. Its toxicity also varies with its origins of production or batches. The symptoms of strychnos nuxvomica poisoning vary. The autopsy findings mainly include pathological changes caused by acute disorder of blood circulation, characterized by the congestion and edema of organs or pinpoint bleeding of mucosa or serous membrane. Long-term toxicity test revealed no characteristic pathological changes of vital organs in animals. For the detection of poisonous substances, the stomach tissue or stomach contents are the best choices, and urine, intestinal contents are the next best materials. Liver, brain and spinal medulla also have high level of strychnos nuxvomica after poisioning. In the forensic identification of strychnos nuxvomica poisoning, it is important to eliminate the other death causes, than get sufficient information concerning the source of the herb (variety, batch, origin of the product), the physical condition (metabolic status) of the patients or victim, dosage, and take the symptoms, pathological changes into consideration. Because of its accumulation, the possibility of the drug being given multiple-times and in small-dose should be considered. The detection of strychnos nuxvomica and quantitative analysis is essential and most reliable in the identification of strychnos nuxvomica poisoning. Exceptionally, great care should be exercised to differentiate it from the intoxication of tetra mine, fumarin and armazide and other spasm-causing agents.