High-resolution manometry reveals different effect of polyethylene glycol, bisacodyl, and prucalopride on colonic motility in healthy subjects: An acute, open label, randomized, crossover, reader-blinded study with potential clinical implications.

Background: Polyethylene glycol (PEG), bisacodyl, and prucalopride have been reported to be more effective than placebo in treating patients with constipation but about 50% of the patients still do not respond to these medications. Only bisacodyl and prucalopride are expected to directly stimulate the colonic motility in humans in vivo. As no previous study has done this, the aim of the study was to investigate the effect of PEG, bisacodyl, and prucalopride as compared to placebo on colonic motility assessed by means of the high-resolution manometry (HRM) in healthy subjects.

Methods: Ten healthy subjects have been enrolled in an acute, open label, randomized, reader-blinded, crossover study and requested to undergo a colonoscopy-assisted HRM measuring their colonic motility before and after oral administration of 13.8 g (two doses) PEG, 10 mg bisacodyl, 2 mg prucalopride, and placebo.

Key Results: In the human prepared colon, oral administration of PEG significantly increases the number of low-amplitude long distance propagating contractions (p = 0.007 vs placebo) while bisacodyl significantly increases the number of high-amplitude propagating contractions (HAPCs) (all p < 0.01 vs PEG, prucalopride, and placebo). Prucalopride has no major effect on the number of propagating contractions but increases HAPCs amplitude (p = 0.01).

Conclusions & Inferences: In humans, PEG, prucalopride, and bisacodyl have distinct effects on colonic motility. This information has clinical implication, as it indicates that the combination of prucalopride and bisacodyl, normally not considered in clinical practice, could be effective in treating patients with constipation refractory to single medications.