Effect of cisapride on morphine absorption after oral administration of sustained-release morphine

We investigated the effect of cisapride 20 mg given orally with MST 20 mg on the absorption of morphine in a double-blind, placebo-controlled study. Cisapride increased significantly both plasma concentrations of morphine after 1 h and peak concentrations. There was no significant change in time to peak concentrations, sedation scores or percentage decrease in pupil diameters. Plasma concentrations of amylase were increased in three patients in the MST-placebo group and three in the MST-cisapride group. One patient in the MST-cisapride group developed acute pancreatitis.