Prokinetic effect of indoramin, an α‐adrenergic antagonist, on human gall‐bladder

Summary Background : The effects of α- and β-adrenergic agents on gall-bladder motility remain undefined. Aim : To determine the effects of α- and β-antagonists on gall-bladder motility in healthy humans. Methods : In this single, blind, three-way crossover study, a slow-release formulation of propranolol 80 mg (β-antagonist), indoramin 25 mg (post-synaptic α1-antagonist) and placebo were administered to 10 healthy volunteers on three separate days 8 h before the assessment of gall-bladder volumes by ultrasonography. Gall-bladder volumes were assessed in the fasting state and at 5-min intervals for 50 min after a standard proprietary enteral feed (Ensure 186 mL, Abbott). Results : The fasting gall-bladder volumes of subjects who received placebo or indoramin were significantlydifferent (mean ± S.E.M.: 16.50 ± 2.78 mL and 13.47 ± 2.24 mL, respectively; P < 0.001, two-way analysis of variance). The fasting gall-bladder volume after the administration of propranolol was 17.49 ± 2.37 mL and was not significantly different from placebo (16.50 ± 2.78 mL). When the mean post-prandial gall-bladder volumes were compared, indoramin significantly enhanced post-prandial gall-bladder emptying compared to placebo (P < 0.001). There was no significant post-prandial volume difference between placebo and propranolol. Conclusions : Indoramin, an α-adrenergic antagonist, acts as a prokinetic agent, enhancing post-prandial gall-bladder emptying in healthy individuals.