Prucalopride (R-93877) is a selective, high-affinity 5-HT4A/4B receptor agonist (Ki: 2.5/8 nM). It has >290-fold selectivity for 5-HT4A/4B receptor than other 5-HT receptor subtypes.

Administration of prucalopride at dosages of 2/4 mg resulted in complete spontaneous bowel movements per week at rates of 30.9% and 28.4%, respectively, compared to 12.0% in the placebo group. Patients treated with 2 mg of prucalopride (47.3%) and those receiving 4 mg (46.6%) experienced an increase in the frequency of spontaneous bowel movements, with an average of one or more complete bowel movements per week, versus 25.8% in the placebo group. Prucalopride (2/4 mg) significantly enhanced other secondary efficacy endpoints, including patient satisfaction with their bowel functions and treatment, as well as their perception of the severity of constipation symptoms. At a dosage of 4 mg/day, prucalopride accelerated overall gastric emptying and small intestinal transit without causing intestinal evacuation disorders. It also sped up overall colonic transit and increased the colonic emptying rate.

Prucalopride (1 mM) significantly amplifies the rebound contraction of the guinea pig's proximal colon following electrical stimulation. It induces contractions in a concentration-dependent manner (pEC50: 7.5). Additionally, Prucalopride induces relaxation in the muscularis mucosae of the rat esophagus (pEC50: 7.8), demonstrating a monophasic concentration-response curve.