The influence of anticholinergic drug selection on the efficacy of antidotal treatment of soman-poisoned rats

The influence of some anticholinergic drugs (atropine, benactyzine, biperid en, scopolamine) on the efficacy of antidotal treatment to eliminate soman (O-pinacolyl methylphosphonofluoridate)-induced disturbance of respiration and circulation and to protect experimental animals poisoned with supraleth al dose of soman (1.5 x LD50) was investigated in a rat model with on-line monitoring of respiratory and circulatory parameters. While the oxime HI-6 in combination with atropine prevented soman-induced changes in monitored p hysiological parameters insuficiently and very shortly, the combination of HI-6 with benactyzine or biperiden is able to prevent soman-induced alterat ion of respiration and circulation much more longer. Nevertheless, only rat s treated with HI-6 in combination with scopolamine were fully protected ag ainst the lethal toxic effects of soman within 2 h following soman challeng e. Our findings confirm that anticholinergic drugs with the strong central antimuscarinic activity, such as benactyzine, biperiden and especially scop olamine, seem to be more effective adjuncts to HI-6 treatment of severe acu te soman-induced poisoning than atropine. (C) 2000 Elsevier Science Ireland Ltd. All rights reserved.