Efficacy and tolerability of 2-L polyethylene glycol with ascorbic acid versus sodium picosulfate with magnesium citrate: a randomized controlled trial

Background/aim Previous studies comparing 2-L polyethylene glycol (PEG)-based solution with ascorbic acid (PEG/Asc) with sodium picosulfate/magnesium citrate (SP/MC) drew inconclusive results. This study aimed to compare a 2-L-PEG/Asc with SP/MC by split method in bowel cleansing efficacy, tolerability, and safety and to identify factors influencing inadequate bowel preparation. Method We performed a prospective randomized, endoscopist-blinded, single-center, controlled trial. The Aronchick scale and Ottawa bowel preparation scale (OBPS) were used to evaluate the bowel cleansing efficacy, and patients’ tolerability and preferences were assessed by questionnaire. Results In total, 223 patients were randomized to receive 2-L-PEG/Asc ( n = 109) or SP/MC ( n = 114). There was no significant difference in overall bowel cleansing efficacy between the two groups; however, when analyzing by individual segment, mean bowel cleansing efficacy of right colon showed a trend in favor of SP/MC group than in PEG/Asc group (OBPS; 1.55 ± 0.66 vs. 1.74 ± 0.88, P = 0.08). Furthermore, SP/MC was better tolerated than PEG/Asc based on ease of consumption and preference to receive the agents again in the future. Total adverse events were significantly lower in SP/MC group than PEG/Asc group (47.4 vs. 62.4%, P = 0.031). In multivariate analysis, later colonoscopic starting time was the only independent factor predicting inadequate bowel preparation (OR 1.39, 95% CI 1.156–1.692, P = 0.001). Conclusions There was no significant difference in overall bowel cleansing efficacy between PEG/Asc and SP/MC; however, SP/MC showed better tolerability and safety profile than PEG/Asc. The independent factor for inadequate bowel preparation was later colonoscopic starting time when applied split method.