title: L-menthol improves adenoma detection rate during colonoscopy: a randomized trial.
abstract: OBJECTIVE
  Colonoscopy is one of the most reliable methods for the detection of colorectal neoplasms. However, colonic peristalsis during colonoscopy results in some neoplastic lesions being hidden from view and commonly requires an intravenous or intramuscular injection of antispasmodic agents, which may sometimes causes unexpected adverse reactions. The aim of this study was to evaluate the efficacy of L-menthol spray as an antiperistaltic agent and its effect on adenoma detection.
  
  
  METHODS
  This was a prospective, randomized, single-blind placebo-controlled trial. A total of 226 patients who were scheduled to undergo colonoscopy were randomly assigned to receive either 20 mL of 1.6 % L-menthol (n = 118) or placebo (n = 108). Both treatments were sprayed locally onto the colonic mucosa via an endoscope. The adenoma detection rate (ADR) and the proportion of patients with no peristalsis were the primary and secondary outcomes, respectively.
  
  
  RESULTS
  The ADR was significantly higher in the L-menthol group than in the placebo group (60.2 % vs. 42.6 %; P = 0.0083). The proportion of patients with no peristalsis after treatment with L-menthol was significantly higher than in the placebo group (71.2 % vs. 30.9 %; P < 0.0001). There were no adverse effects in either group.
  
  
  CONCLUSIONS
  The results suggest that the suppression of colonic peristalsis by L-menthol sprayed directly onto the colonic mucosa improves the ADR.
  
  
  BACKGROUND
  ID: UMIN 000007972.
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, North Medical Center Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Ken
authors.initials: K
authors.lastname: Inoue
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, North Medical Center Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Dohi
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, North Medical Center Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Gen
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, North Medical Center Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Masayasu
authors.initials: M
authors.lastname: Jo
authors.affiliation: Department of Surgical Pathology, North Medical Center Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Mazaki
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, North Medical Center Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Tokita
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Naohisa
authors.initials: N
authors.lastname: Yoshida
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Okayama
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Kamada
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Kazuhiro
authors.initials: K
authors.lastname: Katada
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Kazuhiko
authors.initials: K
authors.lastname: Uchiyama
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Takeshi
authors.initials: T
authors.lastname: Ishikawa
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Osamu
authors.initials: O
authors.lastname: Handa
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Tomohisa
authors.initials: T
authors.lastname: Takagi
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Hideyuki
authors.initials: H
authors.lastname: Konishi
authors.affiliation: Department of Gastroenterology, Otsu City Hospital, Shiga, Japan.
authors.forename: Naoki
authors.initials: N
authors.lastname: Wakabayashi
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Yagi
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Naito
authors.affiliation: Department of Molecular Gastroenterology and Hepatology, Kyoto Prefectural University of Medicine, Kyoto, Japan.
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Itoh
mesh_terms: D000236:Adenoma / Q000175:diagnosis*; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000930:Antidiarrheals / Q000008:administration & dosage* / Q000009:adverse effects; D003106:Colon / Q000187:drug effects; D003110:Colonic Neoplasms / Q000175:diagnosis*; D003113:Colonoscopy / Q000379:methods*; D005260:Female; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects; D008297:Male; D008610:Menthol / Q000008:administration & dosage* / Q000009:adverse effects; D008875:Middle Aged; D010528:Peristalsis / Q000187:drug effects*; D011446:Prospective Studies; D016037:Single-Blind Method
chemical_list: D000930:Antidiarrheals; D008610:Menthol