Behavioural and physiological assessments of dimethyl trisulfide treatment for acute oral sodium cyanide poisoning.

Abstract

Sodium cyanide (NaCN) is a commonly and widely used industrial and laboratory chemical that is highly toxic. Its availability and rapid harmful/lethal effects combine to make cyanide a potential foodborne/waterborne intentional-poisoning hazard. Effective antidotes to cyanide poisoning are currently approved only for intravenous administration. Therefore, an effective cyanide antidote that can be administered intramuscularly in pre-hospital and/or mass-casualty settings is needed. Dimethyl trisulfide (DMTS) is a naturally occurring substance used as a flavour enhancer in foods. DMTS has shown antidotal efficacy in cyanide poisoning and is thought to act as both a sulphur donor and partial methaemoglobin inducer. In this study, an intramuscular injection of DMTS (6.25-200mg/kg) was given to rats 1minute after an oral dose of NaCN (98.2mg/kg; twice the median lethal dose) to test the antidotal efficacy and safety of DMTS treatment. Toxic signs and survival were examined along with behavioural function (up to 30hour after ingestion) using a previously established operant behavioural model. A large range of DMTS doses (6.25-100mg/kg) increased survival after oral cyanide poisoning, and the lower DMTS doses (6.25-25mg/kg) also proved to be behaviourally and physiologically safe. Larger DMTS doses (50-200mg/kg) produced side effects (ie, inflammation and limping) that were more severe and protracted than those observed at lower DMTS doses. The 25mg/kg DMTS proved to be the most efficacious (increasing survival from 20% to 75%) and also produced minimal side effects (eg, inflammation) that resolved within 24-72hour. Thus, DMTS shows promise as an intramuscularly administered cyanide antidote useful for prompt pre-hospital or mass-casualty emergency medical treatment.