Efficacy of atropine/pralidoxime/diazepam or atropine/HI-6/prodiazepam in primates intoxicated by soman

We performed an experiment to characterize the toxicity of soman in cynomolgus monkeys when the organophosphorus intoxication was followed by a treatment with either the three-drug therapy atropine/pralidoxime/diazepam or the association atropine/HI-6/prodiazepam. Clinical, electrophysiological and histological approaches were combined. Our data demonstrate that the protection afforded against soman toxicity was better with the combination atropine/HI-6/prodiazepam compared to atropine/pralidoxime/diazepam. This was observed transiently in term of vigilance and respiratory function of intoxicated animals, but particularly in term of their EEG- and ECG disturbances. Moreover, compared to those treated with atropine/pralidoldme/diazepam, animals treated with atropine/HI-6/prodiazepam recovered slightly sooner and did not exhibit prostration 2 days after intoxication although their rapidity of movements was not totally restored. The final recovery observed 3 weeks after intoxication was similar for the two groups. The value of the combination of atropine/HI-6/prodiazepam vs atropine/pralidoxime/diazepam to counteract soman toxicity was also confirmed in term of brain neuroprotection since greater lesions were observed with the second three drug treatment three weeks after intoxication. Copyright (C) 1997 Elsevier Science Inc.