ORAL PROPHYLAXIS FOR ANTICHOLINESTERASE POISONING

Abstract

A method of protection against poisoning by cholinesterase inhibitors involving the use of N-methyl pyridinium-2-aldoxime methanesulphonate (P-2-S) orally, prior to exposure to the anticholinesterase agent, in combination with intramuscularly administered atropine sulphate after exposure, has been examined. In rats poisoned with O,O-diethyl S-2-diethylaminoethyl phosphorothiolate (DSDP), the treatment permitted survival from a dose of 28 times the LD₅₀ in untreated animals. The protection given by oral P-2-S lasts for an extended period of time decreasing to one half the maximum value in about 4 hours. Mice, guinea pigs, and rabbits so treated demonstrated a high tolerance to DSDP but of lower order than the rat. Treatment with oxime and atropine afforded protection to mice and rats exposed to paraoxon, vinylphosphate, isosystox, DFP, TEPP, and eserine, but was relatively impotent against sarin, tabun, and schradan. The possible application of this mode of treatment to human exposures to anticholinesterase agents is discussed.