The primary aim of the study was to test if the administration of Hyoscine Butyl Bromide, at time of caecal intubation, increases the adenoma detection rate.

Outpatients referred for colonoscopy were screened for possible enrollment. Exclusion criteria included: glaucoma, benign prostatic hyperplasia or urinary obstruction, previous intestinal resection, ongoing therapy with tricyclic antidepressants, chronic renal failure and history of IBD. Eligible patients were randomized to receive either 20 mg/2ml of HBB i.v. or 2ml of saline i.v.; both the endoscopist and the patient were blind to the administered drug. The endoscopist was asked to inspect the right, transverse and left colon for at least 2 min for each segment. The number, size and location of polyps were recorded as well as the occurrence episodes of tachycardia (defined as bpm>140). As indirect estimation of the amount of air retained in the abdomen at the end of the procedure, the DAC (difference in the abdominal circumference measured before and after colonoscopy) was also calculated. At discharge (at least 1 hour after colonoscopy) the bloating perceived by the patient was measured by means of a VA scale (range 0-100).

Inclusion Criteria:

• outpatients referred for colonoscopy

Exclusion Criteria:

• glaucoma
• benign prostatic hyperplasia or urinary obstruction
• previous intestinal resection,
• ongoing therapy with tricyclic antidepressants
• chronic renal failure
• history of IBD
• participation other studies
• unsedated colonoscopy