Relative potency of the atropine-like effects of a new parasympatholytic drug, scopolamine-N-(cyclopropyl methyl) bromide and those of hyoscine-N-butyl bromide.

A double-blind crossover trial with a 4-point bioassay was carried out in 8 convalescent in-patients to study the relative potency of scopolamine-N-(cyclopropyl methyl) bromide (DA 3177), a new parasympatholytic drug, administered at doses of 2.5 mg and 5 mg i.v., and hyoscine-N-butyl bromide, administered at doses of 10 mg and 20 mg i.v., in producing atropine-like effects. The results showed that the effects on heart rate and near point of accommodation were slightly less with DA 3177, while its effects on salivary secretion were a little greater than those of hyoscine-N-butyl bromide. It is suggested that study of the pharmacodynamic effects of parasympatholytic drugs is a relatively simple way of predicting which doses should be effective spasmolytically.