Studies on the therapeutic effect of 2-pyridine aldoxime methiodide (2-PAM) in mammals following organophosphorus compound-poisoning (report III): distribution and antidotal effect of 2-PAM in rats.

The metabolic fate of 2-PAM and its antidotal effect on organophosphorus compound poisoning in rats were studied. When 14C-2-PAM was administered intravenously, the amount of 14C reaching the brain was small. Following administration by intramedullary injection, 14C was present in high concentrations in the brain, and 72-90% of the 14C present in the brain corresponded to the unchanged form of 2-PAM. 2-PAM was rapidly excreted into the urine and feces following either intramedullary or intravenous administration. The half-life of 2-PAM in the brain following intramedullary administration was 1.52 hr. Intramedullary administration of 2-PAM to rats poisoned with fenitrothion or malathion enabled their survival and induced reactivation of brain cholinesterase.