Ultrasound studies of the effect of trospium chloride on gall-bladder kinetics

In a randomized double-blind study the effects of increasing doses of trospium chloride (Spasmo-lyt, CAS 10405-02-4), 0.2, 0.5, 1.0, and 1.5 mg i.v., on gall-bladder contractility were compared among themselves and against placebo and n-butylscopolamine bromide (20 mg i.v.) by an intraindividual 5-fold crossover technique. Gall-bladder volumes after drug-induced contraction (fat stimulus with sodium iopodate) were measured by ultrasound scanning conducted by a single examiner. Serial measurements, carried out in 6 female subjects without any evidence of gall-bladder disease, demonstrated a dose-dependent trend of inhibition of gall-bladder motility produced by trospium chloride. In the maximal doses employed (1.0 and 1.5 mg i.v.) trospium chloride effected almost total inhibition of motility. The response to n-butylscopolamine bromide tested in a nonblind comparison, showed a dose-effect ratio of roughly 40:1 between trospium chloride and n-butylscopolamine bromide given intravenously. This work confirms that ultrasound measurement of gall-bladder volume is a suitable pharmacodynamic model for testing the dose-effect relationships of antispasmodic agents.