Background. The composition of the causal antidotal therapy of subjects, poisoned with organophosphorus insecticides, has not been satisfactorily solved till now in spite of the knowledge of the basic mechanism of action of these toxic substances. The purpose of this study is to evaluate which of currently used or perspective acetylcholinesterase reactivators seems to be the most efficacious to protect poisoned subjects. Methods and Results. In experiments on white laboratory rats, the reactivating efficacy of selected acetylcholin- esterase reactivators (oximes), administered at equimolar doses, was evaluated in target tissue of toxic effects of organophosphorus insecticides (diaphragm, brain) and compared with their therapeutic efficacy in the case of prophylactic administration with the help of the evaluation of mean efficacy dose of oximes, possible to protect rats exposed to supralethal dose of organophosphorus insecticide fosdrin for 24 hours. Our findings confirm that there are not statistically significant differences in reactivating and therapeutic efficacy of oximes tested against fosdrin in rats. Conclusions. The perspective acetylcholinesterase reactivators (H oximes) seem to be as suitable as currently used oximes for the therapy of acute poisonings with organophosphorus insecticides although they are not significantly more efficacious than currently used oximes as in the case of the treatment of poisoning with highly toxic organophosphorus compounds.

        Key words: fosdrin, rat, HI-6, BI-6, obidoxime, methoxime, pralidoxime, atropine.