The effect of cisapride on defaecation in normal human subjects—lack of effect on faecal excretion of water, fat, and bile acids

SUMMARY In order to elucidate whether or not the increased stool frequency that occurs during cisapride treatment is a result of malabsorption of water, fat, and bile acids, 12 healthy volunteers were dosed with either tablets of placebo q.d.s. or tablets of 10 mg cisapride q.d.s. during two periods of 5 days in a double-blind, crossover study. Stool frequency, stool consistency, and side-effects were recorded each day. Total faecal mass, faecal water content, and faecal excretion of fat and bile acids were determined during the last 72 h of each study period. Mean daily stool frequency was 18.8% higher during cisapride [1.68 ± 0.12 (S.E.M.)] administration than during placebo (1.42 ± 0.12); P= 0.038. The stool consistency score increased by 11.8% towards softer stools during cisapride dosing (N.S.). There were no significant differences in total faecal mass (placebo 399.4 g/72 h; cisapride; 414.5 g/72 h), faecal water content (placebo; 75.6%: cisapride 76.2%), or faecal excretion of fat (placebo; 12.7 g/72 h: cisapride; 11.6 g/72 h) and total bile acids (placebo; 2212 μmol/72 h: cisapride; 2261 μmol/72 h). The side-effects reported during placebo were constipation (n = 3), and during cisapride meteorism (n = 4) and increased appetite (n = 2). The increased stool frequency during cisapride treatment is not caused by malabsorption of water, fat, or bile acids, but seems to be the consequence of a direct motor effect.