Effect of Intraluminal Administration of Menthol Solution During Colonoscopy on Colonic Spasm and Adenoma Detection Rate

In recent years, with increasing research into antispasmodic agents, topical antispasmodics have attracted considerable attention due to their direct action on the gastrointestinal mucosa and relatively low incidence of adverse reactions. Menthol, a natural terpenoid compound found in peppermint oil, has been confirmed by numerous studies to possess spasmolytic properties. Existing evidence indicates that menthol relaxes intestinal smooth muscle and alleviates spasm symptoms by antagonizing L-type calcium channels on the smooth muscle cell membrane, thereby reducing calcium influx. Furthermore, it exhibits local analgesic effects and can attenuate visceral hypersensitivity. Some studies suggest that oral or topical administration of peppermint oil preparations may improve intestinal spasm during colonoscopy, highlighting its potential utility in digestive endoscopy procedures. Nevertheless, current research on the spasmolytic efficacy and safety of menthol solution when administered via endoscopic irrigation during colonoscopy remains limited, and high-quality clinical trials are urgently needed for validation. This study aims to investigate the effectiveness and safety of menthol solution in relieving intestinal spasm, thereby providing scientific evidence for optimizing colonoscopy procedures.

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Key information

Conditions

Colonoscopy

Age range

18 year–75 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Not applicable

Who can participate

Healthy volunteers accepted: Yes

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

Age between 18 and 75 years, regardless of gender;
Scheduled to undergo colonoscopy (for screening, diagnostic, or follow-up purposes);
Adequate bowel preparation quality (Boston Bowel Preparation Scale score ≥ 6);
Voluntarily signed informed consent and able to cooperate with completing study-related assessments.

Exclusion criteria

Allergy to menthol, cyclodextrin, or related substances;
History of severe intestinal diseases (such as ulcerative colitis, Crohn's disease, intestinal perforation, intestinal obstruction, intestinal tumors, etc.);
Presence of severe dysfunction of vital organs such as the heart, liver, kidneys, or lungs, or coagulation disorders;
Pregnant or lactating women;
Use of anticholinergic drugs, calcium channel blockers, or other spasmolytic agents within one week prior to the examination;
Psychiatric disorders or cognitive impairment that prevent cooperation with the study;
History of contraindications to colonoscopy or serious adverse reactions during previous procedures.

Treatment and study plan

Endoscopic irrigation was performed using a 0.1% menthol solution combined with simethicone.

Drug

Preparation method: Normal saline was used as the solvent. Menthol cyclodextrin inclusion complex (containing 7.3% menthol) was accurately weighed at 6.85 g and dissolved in 500 ml of normal saline to prepare a 0.1% menthol solution. After complete dissolution, 5 g of simethicone was added to form an aqueous suspension.

Endoscopic irrigation was performed using an aqueous suspension prepared with simethicone and normal saline.

Drug

Preparation method: 5 g of simethicone was added to 500 ml of normal saline to form the aqueous suspension.

Primary outcomes

Incidence of intestinal spasm

Time frame: Day 0

Intestinal spasm score:

Score 1 (Excellent): No spasm; the lumen opening is greater than or equal to two-thirds of the maximum diameter.

Score 2 (Moderate): Moderate spasm; the lumen opening is less than two-thirds of the maximum diameter.

Score 3 (Poor): Severe spasm; the oral-side lumen cannot be visualized.

The maximum diameter is defined as the diameter of the intestinal lumen when fully distended.

Spasm incidence: The percentage of patients with an intestinal spasm score of 2 or 3 out of the total number of patients in the group.
adenoma detection rate (ADR)

Time frame: Day 0

ADR = (Number of patients with at least one adenomatous polyp detected / Total number of patients in the group) × 100%.

Pathological diagnosis was used as the gold standard.

Secondary outcomes

Spasm inhibition rate

Time frame: Day 0

The percentage of patients whose lumen opening exceeded two-thirds of the maximum diameter within 30 seconds after water injection irrigation, relative to the total number of patients in the group.
Polyp detection rate (PDR)

Time frame: Day 0

PDR = (Number of patients with at least one polyp detected / Total number of patients in the group) × 100%.

Study contacts

Contact information is provided by the study sponsor or research team.

Jianning Yao

CONTACT

[email protected]

13733183434

Sponsors and collaborators

Lead sponsor

The First Affiliated Hospital of Zhengzhou University

Other

Registry information

Official study title

Effect of Intraluminal Administration of Menthol Solution During Colonoscopy on Colonic Spasm and Adenoma Detection Rate: An Efficacy and Safety Study

Important dates

Study start: 2026
Primary completion: 2026
Study completion: 2026
First posted: Mar 30, 2026
Registry last updated: Mar 30, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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