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 α 1 ‐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.