Bisacodyl is a stimulant laxative often used in manometric studies of pediatric constipation to determine if it can initiate propulsive high amplitude propagating contractions. While the effects of bisacodyl infusion on colonic motility are well described, the effects of the drug on other regions of the gut after colonic infusion are not known. The aim of the present study was to characterize the effects of bisacodyl on both colonic and small bowel motility. Methods. Twenty seven children (9.3 + 1.2 years) undergoing simultaneous high resolution antroduodenal and colonic manometry were included. Small bowel and colonic motor patterns were assessed prior to and after colonic infusion of bisacodyl. Patients were divided into 2 groups; responders and non-responders based on the presence of high amplitude propagating contractions (HAPC) after bisacodyl infusion. Results. Nineteen patients were responders. 188 post-bisacodyl HAPCs were identified with a mean count of 10.4 ± 5.5 (range, 3 -22), at a frequency of 0.6 ± 0.2/min and mean amplitude of 119.8 ± 23.6 mmHg.No motor patterns were induced in the small bowel. However, in the 19 responders the onset of HAPCs was associated with a significant decrease in small bowel contractile activity. In the non-responders there was no detectable change in small bowel motility after bisacodyl infusion. Conclusion. Bisacodyl induced HAPCs are associated with a significant reduction in small bowel motility probably mediated by extrinsic sympathetic reflex pathways. This inhibition is potentially related to rectal distension, caused by the HAPC anal propulsion of colonic content.
Internal anal sphincter relaxation associated with bisacodyl-induced colonic high amplitude propagating contractions in children with constipation: a colo-anal reflex?
