Objective: There is no data available on the efficacy of bowel preparation among constipated patients. This study aims to compare the bowel cleansing efficacy, safety, tolerability, acceptability, compliance, and satisfaction of triple-dose and split-dose polyethylene glycol electrolyte lavage solution (PEG-ELS) before colonoscopy in patients with constipation.

Materials and Methods:A prospective, multicenter, endoscopist-blinded, randomized controlled trial was conducted in 4 hospitals in northeast Thailand. Seventy-six participants who were eligible for colonoscopy were randomly allocated toeither triple-dose or split-dose PEG-ELS before colonoscopy.The quality of bowel preparation was assessed using the Ottawa Bowel Preparation Scale (OBPS).

Results:The mean overall OBPS score and the rate of successful bowel cleansing (total OBPS score ≤6) in the per-protocol analysis were significantly superior in the triple-dose group compared with the split-dose group (4.1± 2.4 vs 5.4±1.9, p = 0.014, and 91.4% vs 73.0%, p = 0.042, respectively). There were no clinically significant differences in renal function, electrolyte abnormalities, adverse events, or patient acceptance, compliance, or mean satisfaction between the two groups.

Conclusions: The triple-dose PEG-ELS was found to be superior to the split-dose bowel preparation before colonoscopy in constipated patients, and there were no serious side effects.