Prokinetic effect of indoramin, an alpha-adrenergic antagonist, on human gall-bladder

The effects of alpha- and beta-adrenergic agents on gall-bladder motility remain undefined.

To determine the effects of alpha- and beta-antagonists on gall-bladder motility in healthy humans.

In this single, blind, three-way crossover study, a slow-release formulation of propranolol 80 mg (beta-antagonist), indoramin 25 mg (post-synaptic alpha1-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).

The fasting gall-bladder volumes of subjects who received placebo or indoramin were significantly different (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.

Indoramin, an alpha-adrenergic antagonist, acts as a prokinetic agent, enhancing post-prandial gall-bladder emptying in healthy individuals.