Effects of Hyosine N-butyl bromide on the detection of polyps during colonoscopy

Colonoscopy has a significant miss rate for colorectal polyp screening. The present study hypothesized that reduced colonic spasm with antispasmodic agents might yield a better visual field to result in enhanced polyp detection rate.

In a prospective, randomized, double-blind study design, muscle spasm was recorded during insertion and withdrawal during routine colonoscopy, and the number of polyps detected were compared between two groups of 58 patients characterized with either hyosine N-butyl bromide (Hyosine group) or placebo (Placebo group) injected at reaching the cecum.

The number of patients with decrease in spasm score of 0, 1, and 2 between insertion and withdrawal were 5 (8.6%), 31 (53.4%), and 22 (37.9%) in the Hyosine group, and 10 (17.2%), 46 (79.3%), and 2 (3.4%) in the Placebo group, respectively (p < 0.001). In patients with spasm score > or = 3 during insertion, more polyps per patient were likely to be detected in the Hyoscine group than the Placebo group (1.21 +/- 2.23 vs. 0.41 +/- 0.91; p = 0.060).

Our study suggests that hyosine might increase the detection rate of polyps in patients with moderate to marked degree of colonic spasm during colonoscope insertion. Further large scale studies are needed to validate our observations.