A comparison of the efficacy of new monopyridinium oximes with the oxime HI-6 against mevinphos in mice.

1. The therapeutic efficacy of three new monopyridinium oximes (2,4-PAEtM, 2,5-PAEtM, 2,5-PAAM) and the bispyridinium oxime HI-6 was evaluated in combination with benactyzine against acute poisoning with the organophosphorus insecticide mevinphos in mice. 2. When mice were treated two min after mevinphos poisoning, no significant differences in the therapeutic effectiveness of tested oximes were observed. They increased the 24h LD50 values of mevinphos about three times in comparison with non-treated intoxicated animals. 3. On the other hand, there were significant differences in their therapeutic efficacy when they were administered 30 sec following mevinphos challenge. The monopyridinium oxime 2,5-PAEtM seems to be the most efficacious against mevinphos toxicity. 4. Use of new monopyridinium oxime 2,5-PAEtM appears to be the improvement in the antidotal treatment of poisoning with organophosphorus insecticide mevinphos in comparison with HI-6.