Although it did not meet stringent recommended endpoints dictated by the FDA and European Medicines Agency, small intestinal-release peppermint oil reduced abdominal pain, discomfort and severity in patients with irritable bowel syndrome, according to study results.
Zsa Zsa Weerts, PhD, of the division of the gastroenterology and hepatology at Masstricht University Medical Center, the Netherlands, and colleagues wrote that despite medical advances, patients often find therapeutic options for IBS unsatisfactory.
“One of the pharmacotherapeutic entities currently used is peppermint oil,” researchers wrote. “This agent of herbal origin has menthol as its main constituent and is presumed to have several mechanisms of action including intestinal smooth muscle relaxation, modulation of transient receptor potential channel mediated visceral nociception, 5-hydroxytryptamine antagonism, antimicrobial and antifungal effects, and kappa-opioid receptor agonism.”
Researchers performed a double-blind trial of two versions of peppermint oil capsules — small intestinal-release and ileocolonic-release — compared with placebo. They randomly assigned 190 patients with IBS based on Rome IV criteria to receive 182 mg of either peppermint oil capsule or placebo for 8 weeks. A total of 178 patients completed the study.
The primary endpoint — defined by the FDA — was abdominal pain response based on at least a 30% decrease in weekly average of worst daily abdominal pain compared with baseline in at least 4 weeks. The co-primary endpoint was overall relief, defined by the European Medicines Agency. Investigators also assessed abdominal pain, discomfort, symptom severity and adverse events.
Weerts and colleagues found that peppermint oil did not offer a significantly different response with 46.8% of patients in the small intestinal-release group achieving response compared with 41.3% in the ileocolonic-release group and 34.4% in the placebo group. They also found no significant difference among the groups in overall relief.
However, researchers found that the small intestinal-release peppermint oil produced greater improvement in the secondary outcomes of abdominal pain (P = .016), discomfort (P = .02) and IBS severity (P = .02) compared with placebo. They found no benefits for the ileocolonic-release peppermint oil.
Weerts and colleagues wrote that while adverse events were more common in the peppermint oil groups, they were “mild and transient.”
“This indicates a rather good tolerability of peppermint oil when administered with a gradual titration schedule for the first week,” they wrote. “Thereby, the current results show, in our opinion, that small-intestinal release peppermint oil does have a moderate efficacy in patients with IBS and should not be ignored as a treatment option in everyday practice.” – by Alex Young
Disclosures: Weerts reports financial support from Will Pharma to attend a scientific meeting. Please see the full study for all other authors’ relevant financial disclosures.