Effect of oral erythromycin on colonic transit in patients with idiopathic constipation. A pilot study.

Erythromycin, a motilin receptor agonist has been shown to have prokinetic effects on the upper gastrointestinal tract and gallbladder. Colonic effects of the drug are controversial, and it is debated whether human colon contains motilin receptors. In this study we evaluated the effects of erythromycin on colonic transit and stool frequency in 11 patients with idiopathic constipation over a 1-month period in an open study. The dose used was 1 g/day for two weeks followed by 500 mg/day for another two weeks. The mean (SE) total and segmental colonic transit was measured before and seven days after therapy in seven of these patients. A daily record of stool frequency was maintained in all 11 patients. Erythromycin shortened the total colonic transit from 86.2 (14.6) to 44.8 (8.99) hr (P < 0.01); however, segmental transit studies revealed a significant effect (P < 0.01) only in the right colon and rectosigmoid region. No significant side effects were observed with short-term therapy. These preliminary results suggest that erythromycin is of therapeutic value in patients with idiopathic constipation.