Low volume polyethylene glycol combined with senna versus high volume polyethylene glycol, which regimen is better for bowel preparation for colonoscopy? A randomized, controlled, and single‐blinded trial

Bowel preparation affects the quality of colonoscopy. Reaching the optimal preparation has been a challenge for years. Polyethylene glycol (PEG) is the sole FDA-approved substance for this purpose. However, patients find it unpleasant and often complain about its adverse effects. In this study, we aimed to reduce these complaints by lowering the amount of PEG and adding senna which is an herbal stimulant laxative.Four hundred and eighty-six patients were admitted for colonoscopy. Finally, 382 patients were enrolled in the study and we divided them into two groups; 186 patients were placed in which conventional high volume PEG-alone regimen was consumed and 196 patients in which low volume PEG plus senna regimen was offered. The quality of colon preparation was compared between the two groups by independent two samples t-test (or its corresponding nonparametric test), Fisher's exact, or χ2 test in SPSS software version 22.The colon preparation quality was equally efficient in the two groups as 69.36% in the high volume PEG group and 71.94% in PEG plus senna group had adequate bowel preparation (p = 0.58). Adverse effects, like nausea, bloating, headache, and sleeplessness were significantly less in the low volume PEG plus senna group.Besides the fact that bowel preparation by low volume PEG plus senna combination was noninferior to the conventional high volume PEG-alone regimen, the side effects were much less common with the low volume PEG plus senna regimen.