Some Aspects of the Pharmacology of Clemizole Hydrochloride*

Abstract

Experiments have been described which demonstrate effective prolonged antihistaminic activity and other aspects of the pharmacology of clemizole HC1 (1-p-chloro-benzyl-2-pyrrolidyl-methyl-benzimidazole hydrochloride). A relatively high degree of antihistaminic specificity was observed in both in vitro and in vivo experiments. Clemizole was highly effective in antagonizing histamine aerosol bronchospasm. Spontaneous activity of isolated rabbit ileum and intestinal motility in anesthetized dogs were decreased. There was no significant effect on histamine-induced gastric secretion in chronic gastric fistula dogs. Enhanced responses to epinephrine appear to be due to a sensitization to this amine by the antihistamine.

Acute and chronic studies showed a relatively low order of toxicity.