Objective: To investigate whether dose tapering and, potentially, withdrawal of cisapride is possible without loss of therapeutic effect.
Patients: A total of 119 patients with chronic constipation (less than three spontaneous, i.e., not laxative-induced, stools per week).
Design: Randomized double-blind study.
Methods: Group A (n = 56) was treated with cisapride 20 mg twice daily for 12 weeks. Treatment was continued for a further 12 weeks during which the patients were allowed to take a maximum of four tablets containing 5 mg cisapride each (maximum daily dose, 20 mg). Group B (n = 63) was treated with cisapride 20 mg twice daily for 6 weeks and then with cisapride 10 mg for 6 weeks. Treatment was then stopped and follow-up was continued for a further 12 weeks.
Results: Stool frequency was increased in both groups during active treatment and was not reduced when the dose was decreased from 20 mg to 10 mg twice daily in group B but was maintained in group A. Laxative intake fell by 50% in both groups, but this effect was maintained during follow-up in group A only. Group A patients took nearly the maximum dosage of cisapride tablets allowed during follow-up (3.3 tablets per day +/- 0.2 SEM).
Conclusion: This study confirmed the efficacy of cisapride in chronic idiopathic constipation. Dose tapering below 15-20 mg per day, however, does not appear to be possible.