l-Menthol sprayed on gastric mucosa causes edematous change

Abstract

Background and study aims: l-Menthol (LM), sprayed on the distal gastric mucosa, is a safe antispasmodic agent used during esophagogastroduodenoscopy (EGD). However, it seems to affect gastric mucosal endoscopic findings. Therefore, we evaluated whether LM causes specific changes and impacts the endoscopic morphology of gastric lesions. Patients and methods: A total of 98 patients scheduled to undergo EGD were randomly assigned to receive LM solution (160 mg of 0.8 % LM added to 2.5 mL of indigo carmine [IC]; n = 49; LM group) or decuple-diluted IC solution without LM (n = 49; placebo group). We compared the incidence of specific mucosal changes and the difference in the endoscopic findings of several gastric lesions between these groups. Results: Annular-reticular – like mucosal changes appeared immediately after the administration of LM solution. This change was observed in 71.4 % of the LM group compared with 12.2 % of the placebo group (P < 0.01). In the placebo group, this change was observed in 14.7 % of subjects with atrophic gastritis compared with 6.7 % of those without atrophic gastritis (P = 0.39), whereas in the LM group, this change was observed in 84.8 % of subjects with atrophic gastritis compared with 43.8 % of those without atrophic gastritis (P < 0.01). Most early gastric cancers, erosions, and ulcers observed in this study became well demarcated after LM administration, although the incidence of gastric lesions did not differ significantly between the two groups. Conclusion: LM changes the gastric mucosa into edematous mucosa, and this occurs more frequently in atrophic gastric mucosa than in pathologic lesions. LM may facilitate the demarcation of pathologic gastric lesions without intestinal metaplasia.

Clinical Application of L-Menthol in the Upper Gastrointestinal Endoscopic Procedure

“…It is also likely that the same mechanism underlies the additional effectiveness of L -menthol in determining the tumor margin. Mori et al 14) reported that L -menthol application causes an edematous change of gastric mucosa and thereby clarifies the margin of gastric lesions, such as erosion, ulcer, and early stage cancer, which we have also demonstrated in a study using peppermint oil 6) .…”

L-Menthol for Gastrointestinal Endoscopy: A Systematic Review and Meta-Analysis

“…Because the gastric peristalsis was distinctly different from colorectal peristalsis, a subgroup analysis was conducted to differentiate the effects on the different types of peristalsis. Although there was no statistically significant difference between the 2 subgroups, the 2 colonoscopy studies ( 47 , 53 ) included in our meta-analysis showed a higher PNP and PNMP than the remaining 5 gastroscopy studies because the intestinal epithelial cells were the main absorption site for L-menthol ( 64 ) Similar result was found in a gastroscopy study which observed congestive more significant changes in the gastric mucosa of patients with atrophic gastritis after the administration of L-menthol than in patients without atrophy ( 46 ). A potential explanation for this finding is that atrophic gastritis is usually accompanied by intestinal metaplasia and contains some intestinal metaplasia cells that absorb L-menthol.…”

“…A low risk of selection bias was observed for 6 studies (6/8) because they used a computer ( 11 , 45 , 56 , 57 ) and randomization table ( 47 , 53 ) to generate the randomization code. Regarding allocation concealment, the majority of studies (5/8) ( 11 , 45 , 46 , 56 , 57 ) were deemed as displaying a low risk of bias due to the use of opaque sealed envelopes. In terms of attrition bias and reporting bias, no incomplete outcome data and selective reporting were identified in any of the included studies.…”

“…All the included studies mentioned AEs. Two ( 46 , 52 ) only stated that no major side effects occurred, but the exact numbers were not reported. Hence, the remaining 6 studies reporting specific numbers were used for the quantitative synthesis, and 2 of the 6 studies ( 47 , 53 ) declared that no AEs occurred in their trial.…”

“…Hence, L-menthol has also been applied in the clinic, even as a first-line drug ( 34 ), for the treatment of irritable bowel syndrome ( 35 , 36 ) and functional dyspepsia ( 37 – 39 ), and several meta-analyses have assessed and confirmed its effectiveness and safety ( 40 – 44 ). In recent years, accumulating clinical trials have shown that directly spraying L-menthol onto the gastrointestinal mucosa significantly improves spasms ( 45 , 46 ) and the adenoma detection rate (ADR) ( 47 ) during an endoscopic procedure. However, some of the conclusions were inconsistent.…”