Bowel preparation for colonoscopy: a randomized controlled trial comparing polyethylene glycol solution, one dose and two doses of oral sodium phosphate solution.

Objectives: To compare three bowel preparation regimens for colonoscopy in terms of the quality of preparation, the side effects and patient acceptance.

Methods: A total of 299 patients who underwent colonoscopy were randomized to three bowel preparation regimens: polyethylene glycol solution (n = 106), or a single dose (n = 92) or two doses (n = 101) of sodium phosphate solution. The colonoscopists who recorded the quality of bowel preparation were blind to the preparation regimens. The discomforts associated with bowel preparation and patient acceptance of the preparation were also recorded.

Results: Two doses of sodium phosphate solution achieved significantly better bowel preparation than polyethylene solution or a single dose of sodium phosphate solution (p < 0.05). Although two doses of sodium phosphate solution was associated with more dizziness and anal irritation, patients preferred preparation with sodium phosphate solution than with polyethylene glycol solution. Of the 69 patients in the sodium phosphate solution groups who had prior experience of bowel preparation using polyethylene glycol solution, 55 patients (80%) stated that they preferred sodium phosphate solution.

Conclusion: Two doses of sodium phosphate solution achieved better bowel preparation than polyethylene glycol solution and was more acceptable to patients. A single dose of sodium phosphate did not achieve similar bowel preparation to two doses of the solution.