Peppermint Oil Suppresses GI Spasms During Upper Endoscopy

Laurie Barclay, MD

May 02, 2003

May 2, 2003 — Peppermint oil administered intraluminally has superior efficacy and fewer adverse effects than hyoscine-N-butylbromide (hyoscyamine sulfate) for suppression of gastrointestinal (GI) spasms during upper endoscopy, according to the results of a randomized, double-blind, double-dummy trial published in the April issue of Gastrointestinal Endoscopy.

"GI endoscopy without general anesthesia causes a hyperperistaltic state in the stomach, which frequently necessitates the use of antispasmodic agents, such as hyoscine-N-butylbromide, but these drugs have side effects," write Naoki Hiki, MD, PhD, from the University of Tokyo Graduate School of Medicine in Japan, and colleagues. "Peppermint oil is harmless and acts locally to inhibit GI smooth muscle contraction."

In 100 patients, the investigators compared the antispasmodic effects of intramuscular hyoscyamine and a placebo solution given intraluminally via endoscopy, and also the effects of a placebo solution given intramuscularly with those of a peppermint oil solution given intraluminally.

The opening ratio, defined as the percent change in diameter of the pyloric ring before and after the administrations, was significantly higher in the peppermint oil group than in the hyoscyamine group. The contraction ratio, defined as the percent change in diameter between the maximally and minimally opened pyloric ring states, was significantly lower after peppermint oil administration than after hyoscyamine injection.

The time required for disappearance of the antral contraction ring(s) was 97.1 ± 11.4 seconds in the peppermint oil group, compared with 185.9 ± 10.1 seconds in the hyoscyamine group ( P < .0001). Although hyoscyamine injection produced adverse effects such as dry mouth, blurred vision, and urinary retention, there were no significant adverse effects with peppermint oil.

A major study limitation is intramuscular instead of intravenous administration of hyoscyamine, because the longer period required for intramuscular absorption may have affected the time needed for the drug to inhibit peristalsis.

"Peppermint oil solution administered intraluminally can be used as an antispasmodic agent with superior efficacy and fewer side effects than hyoscine-N-butylbromide administered by intramuscular injection during upper endoscopy," the authors write. "In a preliminary study of the effects of Hyoscyamine administered intravenously and peppermint oil solution given intraluminally, a more rapid and potent antispasmodic effect of the latter also was observed. The investigators propose to study the antispasmodic effect of peppermint oil on other smooth muscle structures, such as the major duodenal papilla and the duodenum itself, and the potential use of this agent during ERCP and colonoscopy."

Gastrointest Endosc. 2003;57:475-482

Reviewed by Gary D. Vogin, MD