The effect of sennosides on colonic mucosal histology and bowel preparation

A single high dose of sennosides is often used to optimize bowel preparation for diagnostic procedures. From previous studies it is suspected that sennosides in such a dose cause acute damage to the colonic mucosa. This study was designed to determine any effects of sennosides on histology of colonic mucosa and on bowel preparation.

In a prospective study 171 patients were randomized for bowel preparation. 84 patients received 1 ml/kg (maximal 75 ml) of a syrup containing 2.0 mg/ml sennoside A and B and 3-5 l of a lavage solution (Sen), 87 patients only received 3-5 l lavage solution (NSen). All patients completed a questionnaire on which patient tolerance was scored. Another questionnaire was completed by the endoscopist, recording quality of the preparation. From the 40 patients with a normal colon (19 Sen, 21 NSen) a biopsy was taken from the sigmoid colon and analyzed for morphological abnormalities. No difference could be demonstrated in tolerance or quality of bowel preparation between the two groups. A marked increase of mononuclear infiltrate in the lamina propria was observed in Sen compared to NSen: in 10/19 vs. 2/21 patients respectively, p < 0.0005.

As these microscopic effects could hamper the interpretation of colonic biopsies, bowel preparation without sennosides is to be recommended.