Background: Treatment of chronic constipation is creating one of the major problems for doctors and patients. Pyridostigmine increases the gastrointestinal motility through the effects on cholinesterase. It seems that this mechanism can reduce chronic constipation. The aim of this study was to compare the effects of pyridostigmine and bisacodyl on chronic constipation.

Methods: This study was conducted on 68 patients who suffered from chronic constipation. Patients were randomly divided into two groups of Pyridostigmine and bisacodyl in which each consisted of 34 patients, respectively. Bristol stool form score, straining defecation, the time of defecation, the number of defecation per week, sense of incomplete evacuation and self-digitation were collected by means of questionnaires and the data were compared.

Results: Sixty-eight patients with the mean age of 68.12±84.49 were studied. The mean difference in the frequency of defecation per week, VAS score, the time to defecation and the Bristol Stool form Scale in pre and post-treatment were 4.33±1.88, 5.96±2.29, 12.30±7.95 min and 2.10±0.95 in pyridostigmine group and 2.96±1.81, 4.06±2.22, 6.67±5.23 min and 1.41±0.84 in bisacodyl group, respectively. The significant difference was observed in both pyridostigmine and bisacodyl groups (P=0.005, P=0.002, P=0.002 and P=0.005, respectively). 60% and 32.3 of patients in pyridostigmine and bisacodyl groups recovered from self-digitations, respectively. In pyridostigmine and bisacodyl groups, 66.7% and 32.3 of them had improvement in the sense of incomplete defecation, respectively.

Conclusion: Pyridostigmine and bisacodyl significantly improved the symptoms of chronic constipation similarly.