comparison of the efficacy of HS-6 versus HI-6 when combined with atropine, pyridostigmine and clonazepam for soman poisoning in the monkey.

Monkeys were exposed to varying doses of soman and given therapy. Therapy consisted of pyridostigmine, clonazepam, atropine and HS-6 or HI-6. Cerebral electrical activity, heart rate, respiration, systemic blood pressure and cholinesterase activity were recorded thoughtout the experiment. The animals in the HS-6 series were divided into 4 groups depending upon the dose of soman; one group received 30 microgram/kg of soman, the second group received 40 microgran/kg. All animals in the HI06 series survived while only one of three monkeys in the fourth group survived. Administration of therapy immediately suppressed all seizure activity and convulsions and the animals appeared awake throughout the experiment. All animals exhibited bradycardia and hypotension following the adminstration of therapy. The cholinesterase activity was depressed after administration of HS-6 therapy. Three of the four monkey that received therapy consisting of HI-6 at a dose of 15 mg/kg survived, while one of two that received HI-6 at a dose of 30 mg/kg survived. The animals that received HI-6 at a dose of 15 mg/kg did not exhibit as severe a decrease in blood pressure as the animals in either the HS-6 series or the monkeys that received HI-6 at 30 mg/kg. In addition, these monkeys were awake and appeared alert throughout the experiment and were up within 4-6 hr post-exposure to soman. The animals that received 30 mg/kg exhibited severe hypotension and did poorly.