EFFECTS OF ATROPINE AND SOMAN ON THE PHARMACOKINETICS OF THE OXIME HLO-7 DIMETHANESULFONATE IN ANESTHETIZED GUINEA-PIGS

The respiratory and circulatory effects and the pharmacokinetics of th e bispyridinium dioxime HLo 7 (30 mu mol/kg) were investigated in guin ea-pigs in combination with atropine (28.8 mu mol/kg) or with atropine plus soman (0.44 mu mol/kg = 5 x LD(50)). The pharmacokinetics and ph armacodynamics were studied in separate groups of animals. HLo 7 had o nly minor effects on circulation and respiration. HLo 7 plus atropine caused a transient, pronounced fall of blood pressure, tachycardia, an d respiratory stimulation. The soman-induced bradycardia was completel y restored by the antidotes, while respiration improved within a few m inutes with the respiratory rate becoming stabilized at 50% of baselin e. 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 HLo 7 did not differ between the groups, i.e. atropine and soman did not affect the kinetics of the oxime.