Effects of atropine and soman on the pharmacokinetics of the oxime HLö 7 dimethanesulfonate in anesthetized guinea-pigs.

The respiratory and circulatory effects and the pharmacokinetics of the bispyridinium dioxime HLö 7 (30 mumol/kg) were investigated in guinea-pigs in combination with atropine (28.8 mumol/kg) or with atropine plus soman (0.44 mumol/kg = 5 x LD50). The pharmacokinetics and pharmacodynamics were studied in separate groups of animals. HLö 7 had only minor effects on circulation and respiration. HLö 7 plus atropine caused a transient, pronounced fall of blood pressure, tachycardia, and respiratory stimulation. The soman-induced bradycardia was completely restored by the antidotes, while respiration improved within a few minutes with the respiratory rate becoming stabilized at 50% of baseline. Plasma half-time (60-70 min), plasma clearance (6-7 ml.kg-1.min-1) and apparent volume of distribution (0.5-0.6 l/kg) of HLö 7 did not differ between the groups, i.e. atropine and soman did not affect the kinetics of the oxime.