Toxicokinetics of Acute Strychnine Poisoning

Abstract

Backround: Strychnine competes with the inhibitory neurotransmitter glycine producing an excitatory state characterized clinically by hyperreflexia, severe muscle spasms, and convulsions. However, the kinetics after overdose have not been well described. Case Report: A 34-year-old male presented to the emergency department 20 minutes after ingesting half of a 250-mL container of 2% strychnine sulfate (2.25 g). The reported lethal dose is 100–120 mg. He was alert and oriented and experiencing muscle spasms. His condition deteriorated prompting sedation, muscle paralysis, and tracheal intubation. He was given activated charcoal 100 g per nasogastric tube. He was admitted to intensive care where he was managed with diazepam, pentobarbital, and pancuronium. Despite mild rhabdomyolysis, he recovered and was extubated on day three. Although receiving prophylactic heparin therapy, a massive fatal pulmonary embolus ensued. Eighteen blood specimens for strychnine analysis were obtained from 20 minutes to 51 hours after ingestion. Serum concentrations were determined with gas chromatography-mass spectroscopy. Disappearance followed a first-order process with a t_1/2, of 16 hours (r² = 0.97). Discussion: Our results confirm the findings of an earlier case report of 19 strychnine levels obtained between 4 and 19 hours which described first-order kinetics with a similar t_1/2, of 10 hours. Conclusion: Strychnine disappearance in this overdose was well described by a first-order process with a t_1/2, of 10–16 hours.