Effect of Simethicone on Colon Preparation During Water Exchange Colonoscopy

NCT07674160 | Not Yet Recruiting

• 1 other identifier: A11403003
• Study Type: interventional
• Target: 180
• Locations: 0 countries
• Sites: N/A

Brief 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.

Conditions

Quality of Bowel Preparation

Keywords

simethicone; Boston Bowel Preparation Scale (BBPS); bubble score; Colon Endoscopic Bubble Scale（CEBuS); adenoma detection rate (ADR); water-exchange (WE) colonoscopy

Outcome Measures

Primary Outcomes (1)

• Boston bowel preparation scale (BBPS)

  Bowel preparation quality assessed using the Boston Bowel Preparation Scale (BBPS). Adequate preparation is defined as a total score ≥6 with all segment scores ≥2.

  At the time of colonoscopy.

Secondary Outcomes (11)

• Bubble score assessed using a 4-point bubble scale

  During the colonoscopy procedure.

• Colon Endoscopic Bubble Scale(CEBuS)

  During the colonoscopy procedure.

• Adenoma detection rate (ADR)

  one week

• Polyp detection rate (PDR)

  one week

• Cecal intubation rate

  At the time of colonoscopy.

Study Arms (2)

Without simethicone group

ACTIVE COMPARATOR

follow a bowel preparation protocol consisting of 10 mg of bisacodyl and 2 liters of PEG solution.

Drug: PEG

With simethicone group

EXPERIMENTAL

Participants received a total of 30 mL of simethicone, with 15 mL added to each 1-liter dose of polyethylene glycol (PEG) solution in the split-dose regimen.

Drug: Simethicone with PEG

Interventions

Simethicone with PEG DRUG

All participants followed a standardized bowel preparation protocol consisting of 10 mg of bisacodyl and 2 liters of PEG solution administered in a split-dose regimen. Participants in the simethicone group additionally received 30 mL of simethicone (600 mg), with 15 mL added to each 1-liter dose of PEG solution.

With simethicone group

PEG DRUG

All participants followed a standardized bowel preparation protocol consisting of 10 mg of bisacodyl and 2 liters of PEG solution administered in a split-dose regimen.

Without simethicone group

Eligibility Criteria

• Age: 20 Years - 80 Years
• Sex: all
• Healthy Volunteers: Yes
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Consecutive patients undergoing screening, surveillance, or diagnostic colonoscopy.
• Procedures performed by participating endoscopists.
• Ability to provide written informed consent.

You may not qualify if:

• Colonoscopy performed using air insufflation or water immersion technique.
• History of colorectal surgery (e.g., colectomy or colostomy).
• Known or suspected colonic obstruction or severe stricture.
• Requirement for inpatient bowel preparation.
• Known allergy or hypersensitivity to simethicone.
• Unable or unwilling to provide informed consent.

Sponsors & Collaborators

• Dalin Tzu Chi General Hospital: lead

Related Publications (12)

• 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.

  PMID: 19554657 RESULT

• 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.

  PMID: 35075814 RESULT

• 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.

  PMID: 36905434 RESULT

• 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.

  PMID: 29132175 RESULT

• 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.

  PMID: 38572443 RESULT

• 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.

  PMID: 28985630 RESULT

• 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.

  PMID: 31451919 RESULT

• 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.

  PMID: 24496417 RESULT

• 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.

  PMID: 21481857 RESULT

• 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.

  PMID: 32355887 RESULT

• 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.

  PMID: 22356322 RESULT

• 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.

  PMID: 33538338 RESULT

MeSH Terms

Interventions

Simethicone

Intervention Hierarchy (Ancestors)

Dimethylpolysiloxanes; Silicones; Siloxanes; Organosilicon Compounds; Organic Chemicals; Polymers; Macromolecular Substances; Biomedical and Dental Materials; Manufactured Materials; Technology, Industry, and Agriculture

Central Study Contacts

Chih -Wei Tseng

CONTACT

+886-5-2648000; cwtseng2@gmail.com

Study Design

• Study Type: interventional
• Phase: not applicable
• Allocation: RANDOMIZED
• Masking: DOUBLE
• Who Masked: INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: HEALTH SERVICES RESEARCH
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: March 3, 2026
• First Posted: June 29, 2026
• Study Start: August 1, 2026
• Primary Completion (Estimated): May 1, 2028
• Study Completion (Estimated): September 1, 2028
• Last Updated: June 29, 2026

Record last verified: 2026-02