L-Menthol for Reducing Bowel Spasm During Colonoscopy

Summary and Comment |
April 11, 2014

L-Menthol for Reducing Bowel Spasm During Colonoscopy

  1. Douglas K. Rex, MD

Despite study limitations, L-menthol spray appeared to improve adenoma detection.

  1. Douglas K. Rex, MD

Bowel spasm during colonoscopy can slow down examinations and might prevent the identification of lesions. Outside the U.S., hyoscine is often given intravenously to counter bowel spasm. Now, researchers in Japan have conducted a randomized, single-blind, placebo-controlled trial of L-menthol spray, another antispasmodic agent, in 226 patients undergoing colonoscopy.

After the cecum was intubated, 20 mL of 1.6% L-menthol or placebo was sprayed onto the cecal mucosa. Within the L-menthol group only, an additional 20 mL dose could be given if significant peristalsis persisted. Few patients received sedation (2% in the L-menthol group and 3% in the placebo group).

The adenoma detection rate was significantly greater in the L-menthol group than in the control group (60.2% vs. 42.6%). The fraction of patients with no peristalsis after treatment was also significantly greater with L-menthol (71.2% vs. 30.9%). No adverse effects were reported.


This study's limitation is that the colonoscopists were not blinded; it is doubtful that effects on adenoma detection of this size would be reproduced in a double-blinded study. Nevertheless, L-menthol spray looks like a very safe way to achieve colon relaxation during colonoscopy. When the colon seems to be collapsing, I have a hard time differentiating whether the condition results from real colon spasm or from the colon deflating as gas escapes through the anus. We certainly see more collapse of the colon walls in deeply sedated patients, which I have attributed to a fully relaxed anal sphincter. We often prevent “colon spasm” by pressing the buttocks together so that air cannot escape. L-menthol appears a lot easier and deserves more investigation.

Editor Disclosures at Time of Publication

  • Disclosures for Douglas K. Rex, MD at time of publication Consultant / Advisory board Given Imaging; Olympus Corporation America; Exact Sciences; Endo Aid Speaker’s bureau Boston Scientific; Braintree Laboratories; Ferring Pharmaceuticals; Olympus America Grant / research support CDC; Olympus America; Boston Medical Center Editorial boards World Journal of Gastroenterology; The Journal of Clinical Gastroenterology; Techniques in Gastrointestinal Endoscopy; Gastroenterology & Hepatology; Expert Review of Gastroenterology & Hepatology; Medscape Gastroenterology; World Journal of Gastrointestinal Pharmacology and Therapeutics; Annals of Gastroenterology & Hepatology; World Journal of Gastrointestinal Oncology; Comparative Effectiveness Research; Journal of Anesthesia & Clinical Research; Gastroenterology; World Journal of Gastrointestinal Pathophysiology; Gastroenterology Research and Practice; GI & Hepatology News; Gastroenterology Report; Clinical Epidemiology Reviews; JSM Gastroenterology and Hepatology Leadership positions in professional societies American Society for Gastrointestinal Endoscopy (Councilor); US Multi-Society Task Forces (AGA, ACG, ASGE) (Chair)


Reader Comments (1)

Glenn Madokoro Physician, Gastroenterology, Newport Beach, CA

We have used menthol as an anti-peristaltic agent, albeit in lower doses than in this paper, for 3 years, since its use was reported for EGD's. It seems to have a mild effect, and its chief asset is that it can work in some patients, and is vastly less expensive tha glucagon, and does not have the potential to cause urinary retention that Levsin or Robinul do.

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