Effect of oral nicardipine on anorectal function in normal human volunteers and patients with irritable bowel syndrome

Paired controlled studies were performed in 10 normal volunteers and 32 patients with irritable bowel syndrome to investigate the effect of the calcium channel blocker nicardipine, on the responses of the anorectum to rectal distension and a meal. Nicardipine was administered orally in standard (20 mg) and sustained-release (30 mg twice a day) formulations. In normal volunteers standard nicardipine had no significant effect on the rectal responses to distension but did significantly reduce the postprandial motility index (P <0.05). In the patients with irritable bowel syndrome, standard nicardipine caused a significant reduction in distension-induced rectal motor activity (P <0.05) and increased the rectal sensory thresholds for desire to defecate and discomfort (P <0.02). Slow-release nicardipine caused a significant reduction in distension-induced activity (P <0.05) but did not alter rectal sensory thresholds. Both formulations of nicardipine significantly reduced the postprandial motility index (P <0.05) and symptoms (P <0.05). In conclusion, this study confirms that calcium channel blockers may be useful in the management of irritable bowel syndrome.