The effects on animals of large doses of laudexium methylsulphate.

LAUDEXIUM METHYLSULPHATE (Laudolissin) is a synthetic curarizing agent (Taylor and Collier, 1951) used in prolonged surgical operations. We have previously described some of its pharmacological properties (Collier and Macauley, 1952) and the purpose of the present paper is to report a further exploration of its pharmacology in relation to its clinical use. As Bovet (1951) has stressed, the toxicity of a neuromuscular blocking agent in animals unprovided with artificial respiration indicates its potency rather than its possible toxicity during anaesthesia. More information may be gained by assessing the toxicity of these agents in animals maintained by artificial respiration and we describe such an assessment of laudexium. Since it seems possible that laudexium may be administered clinically over long periods of time to give muscular relaxation in chronic conditions, we also report results of sub-acute and chronic toxicity tests of the drug in mice.