Effect of Simethicone on Colon Preparation During Water Exchange Colonoscopy

Summary

Background: Colonoscopy reduces colorectal cancer mortality by enabling early detection and removal of adenomas. Its effectiveness, however, depends heavily on bowel preparation quality and mucosal visibility. Simethicone, an anti-foaming agent, decreases intraluminal bubbles and improves visualization; studies in conventional air-insufflation colonoscopy generally show benefits for cleanliness and patient comfort, but evidence in water-exchange (WE) colonoscopy remains limited.Objective: To evaluate whether adding oral simethicone to a split-dose polyethylene glycol (PEG) regimen further improves bowel cleanliness and procedural performance in WE colonoscopy.Methods: Adults undergoing outpatient colonoscopy will be randomly assigned (1:1) to a simethicone group or a control group, with a planned enrollment of 180 participants. All procedures will use the WE insertion technique, and endoscopists will be blinded to group allocation. The primary endpoint is the Boston Bowel Preparation Scale (BBPS); adequate preparation is defined as a total score ≥6 with all segment scores ≥2. Secondary endpoints include bubble score and CEBuS, adenoma detection rate (ADR), polyp detection rate (PDR), cecal intubation rate and time, withdrawal time, volume of water used and flushing/irrigation metrics, and patient-reported tolerability and satisfaction.Expected Results: Compared with PEG alone, adding simethicone is expected to (1) increase the proportion of adequate BBPS preparations, (2) reduce bubble coverage, (3) maintain or potentially improve ADR/PDR, and (4) enhance patient tolerability and satisfaction.Conclusion: If effective, this intervention would provide a simple, low-cost strategy to optimize the quality of WE colonoscopy.

Timeline

Start

2026-08-01

Primary completion

2028-05-01

Completion

2028-09-01

Publications

• Results Tongprasert S, Sobhonslidsuk A, Rattanasiri S. Improving quality of colonoscopy by adding simethicone to sodium phosphate bowel preparation. World J Gastroenterol. 2009 Jun 28;15(24):3032-7. doi: 10.3748/wjg.15.3032.
• Results Cao RR, Wang L, Gao C, Pan JH, Yoshida EM, Li HY, Qi XS. Effect of oral simethicone on the quality of colonoscopy: A systematic review and meta-analysis of randomized controlled trials. J Dig Dis. 2022 Mar;23(3):134-148. doi: 10.1111/1751-2980.13084. Epub 2022 Mar 14.
• Results Sun M, Yang G, Wang Y. Cleaning effect and tolerance of 16 bowel preparation regimens on adult patients before colonoscopy: a network meta-analysis. Int J Colorectal Dis. 2023 Mar 11;38(1):69. doi: 10.1007/s00384-023-04355-3.
• Results Zhang S, Zheng D, Wang J, Wu J, Lei P, Luo Q, Wang L, Zhang B, Wang H, Cui Y, Chen M. Simethicone improves bowel cleansing with low-volume polyethylene glycol: a multicenter randomized trial. Endoscopy. 2018 Apr;50(4):412-422. doi: 10.1055/s-0043-121337. Epub 2017 Nov 13.
• Results Joao M, Areia M, Alves S, Elvas L, Brito D, Saraiva S, Cadime AT. The Effect of Oral Simethicone in a Bowel Preparation in a Colorectal Cancer Screening Colonoscopy Setting: A Randomized Controlled Trial. GE Port J Gastroenterol. 2023 Jun 15;31(2):116-123. doi: 10.1159/000530866. eCollection 2024 Apr.
• Results Bai Y, Fang J, Zhao SB, Wang D, Li YQ, Shi RH, Sun ZQ, Sun MJ, Ji F, Si JM, Li ZS. Impact of preprocedure simethicone on adenoma detection rate during colonoscopy: a multicenter, endoscopist-blinded randomized controlled trial. Endoscopy. 2018 Feb;50(2):128-136. doi: 10.1055/s-0043-119213. Epub 2017 Oct 6.
• Results Moolla M, Dang JT, Shaw A, Dang TNT, Tian C, Karmali S, Sultanian R. Simethicone decreases bloating and improves bowel preparation effectiveness: a systematic review and meta-analysis. Surg Endosc. 2019 Dec;33(12):3899-3909. doi: 10.1007/s00464-019-07066-5. Epub 2019 Aug 26.
• Results Menees SB, Elliott E, Govani S, Anastassiades C, Judd S, Urganus A, Boyce S, Schoenfeld P. The impact of bowel cleansing on follow-up recommendations in average-risk patients with a normal colonoscopy. Am J Gastroenterol. 2014 Feb;109(2):148-54. doi: 10.1038/ajg.2013.243.
• Results Lebwohl B, Kastrinos F, Glick M, Rosenbaum AJ, Wang T, Neugut AI. The impact of suboptimal bowel preparation on adenoma miss rates and the factors associated with early repeat colonoscopy. Gastrointest Endosc. 2011 Jun;73(6):1207-14. doi: 10.1016/j.gie.2011.01.051. Epub 2011 Apr 8.
• Results Sharma P, Burke CA, Johnson DA, Cash BD. The importance of colonoscopy bowel preparation for the detection of colorectal lesions and colorectal cancer prevention. Endosc Int Open. 2020 May;8(5):E673-E683. doi: 10.1055/a-1127-3144. Epub 2020 Apr 17.
• Results Zauber AG, Winawer SJ, O'Brien MJ, Lansdorp-Vogelaar I, van Ballegooijen M, Hankey BF, Shi W, Bond JH, Schapiro M, Panish JF, Stewart ET, Waye JD. Colonoscopic polypectomy and long-term prevention of colorectal-cancer deaths. N Engl J Med. 2012 Feb 23;366(8):687-96. doi: 10.1056/NEJMoa1100370.
• Results Sung H, Ferlay J, Siegel RL, Laversanne M, Soerjomataram I, Jemal A, Bray F. Global Cancer Statistics 2020: GLOBOCAN Estimates of Incidence and Mortality Worldwide for 36 Cancers in 185 Countries. CA Cancer J Clin. 2021 May;71(3):209-249. doi: 10.3322/caac.21660. Epub 2021 Feb 4.

Drugs

Indications

No indication recorded.