Pre-administration of super-low volume polyethylene glycol is as effective as senna laxative as bowel preparation for colonoscopy: a randomized controlled phase 2 trial

Background and purpose Senna laxatives are commonly used for bowel preparation before colonoscopies in Japan. However, this laxative frequently causes complications such as abdominal pain. This study aimed to establish a novel method of bowel preparation, which involved the pre-administration of super-low volume polyethylene glycol (PEG) for three days followed by the same-day administration of low volume PEG. Methods This study was a prospective, multicenter, investigator-blinded, phase 2, randomized control trial. The intake of 13.9 g (120 mL) of PEG or 1 g of a senna laxative for 3 days before the examination was indicated for each group, and 2 L of PEG solution was used for preparation on the examination day. The primary endpoint was the efficacy of bowel cleansing, as assessed by the Boston bowel preparation scale. The secondary endpoints were the adenoma detection rate and occurrence of complications. Results A total of 250 patients were initially enrolled. A total of 122 patients from each group were included in the intention-to-treat analysis. In the intention-to-treat analysis, the responder rates were the same for the two groups (56.6% vs 50.8%). Additionally, the adenoma detection rate did not differ between the two groups (34.9% vs 41.8%, P = 0.3795). In contrast, adherence was higher in the PEG group (93.4% vs 82.8%, P = 0.0101), and the occurrence of complications was lower in the PEG group (1.7% vs 16.4%, P = 0.0001). Conclusion The novel super-low volume PEG method for bowel preparation was as effective as the conventional method with senna laxatives.