A prospective, double-blinded, placebo-controlled randomized trial was conducted to investigate the effect of the antispasmodic hyoscine N-butyl bromide (Buscopan) during colonoscopy.

A total of 120 patients undergoing colonoscopy were randomized to receive either 40 mg of hyoscine N-butyl bromide (n=60) or normal saline solution (n=60) intravenously as premedication. Colonoscopy was performed under patient-controlled sedation. Outcome measures included cecal intubation and total procedure time, demanded and administered doses of patient-controlled sedation, spasm score, pain score, endoscopist satisfaction score, patient willingness to repeat colonoscopy, and vital signs (blood pressure, pulse rate) during colonoscopy.

Mean cecal intubation time in the hyoscine N-butyl bromide group was significantly longer than the control group (12.20 vs. 9.74 minutes; p=0.04; but correction for multiple testing of data removed this significance). The use of hyoscine N-butyl bromide was associated with a significantly lower endoscopist mean satisfaction score (6.47 vs. 7.30; p=0.04; but correction for multiple testing of data removed this significance), higher demanded and administered mean doses of patient-controlled sedation (respectively, 34.80 and 7.25 vs. 24.20 and 5.87; p=0.045; p=0.04, respectively; but correction for multiple testing of data removed these findings of significance), fewer patients willing to repeat colonoscopy (60% vs. 83.9%; p=0.005), and more hemodynamic instability (p<0.001) when compared with the control group. No significant difference was found in the total procedure time, spasm score, or pain score.

Premedication with intravenously administered hyoscine N-butyl bromide impedes colonoscope insertion and causes greater patient discomfort, as well as hemodynamic instability.