Peppermint Oil to Improve Visualization in Screening Colonoscopy: A Randomized Controlled Clinical Trial

Abstract

Background: Screening colonoscopy has been associated with reduced mortality from colorectal cancer by means of early detection and timely treatment. However, visualization during colonoscopy is often impaired since the colon is naturally prone to peristalsis and spasm. There is evidence to suggest benefit of topical peppermint oil in causing smooth muscle relaxation, thereby decreasing peristalsis. The aim of our study was to determine if peppermint oil helps reduce colonic spasticity so as to allow for better visualization during screening colonoscopy.

Methods: We performed a randomized controlled, double-blinded, clinical trial where patients undergoing screening colonoscopy were assigned to receive either peppermint oil or placebo. Once cecum was reached, 50 mL of either solution was directly injected via the working channel of the colonoscope. Colonic peristalsis, spasticity and bowel visibility were documented. Bowel preparation quality, withdrawal time and adenoma detection rate (ADR) were also assessed. Continuous variables were analyzed using t-test or Wilcoxon rank-sum test while categorical variables were compared using the two-way Chi-square test.

Results: Forty-eight patients were included, of whom 24 patients received peppermint oil and 24 received placebo. Mean Boston bowel preparation score (BBPS) was excellent for both groups (8 points vs. 7.9 points; P = 0.98). Both mean total colonoscopy time (17.8 min vs. 21.9 min; P = 0.07) and mean cecal intubation time (7.2 min vs. 10.3 min; P = 0.04) were shorter with peppermint oil as compared to placebo. Complete absence of bowel spasticity was observed among 58.3% patients in the peppermint oil group as compared to 45.8% patients in the placebo group (P = 0.05). More than 75% of bowel was visualized in 83% of patients in both groups (P = 0.56). Mean ADR was higher in the peppermint group as compared to the placebo group (45.8% vs. 37.5%; P = 0.56).

Conclusion: Our study suggests that topical peppermint oil reduces bowel wall spasticity, which could lead to better visualization of the bowel during screening colonoscopy. Although use of peppermint oil was associated with better ADRs, these results did not achieve statistical significance. Larger sample size and use of alternative methods of peppermint oil administration allowing for more absorption time may establish stronger results.




Gastroenterol Res. 2019;12(3):141-147
doi: https://doi.org/10.14740/gr1180