Background: Peppermint oil (PO) has shown promise as an IBS therapy, but previous trials have demonstrated variable efficacy and tolerability results.
Aims: To evaluate the efficacy and tolerability of a novel formulation of PO designed for sustained release in the small intestine in patients with IBS-M and IBS-D.
Methods: This is a 4-week, randomized, double-blind, placebo-controlled clinical trial of PO or identical placebo 3 times daily in patients fulfilling Rome III criteria for IBS-M or IBS-D. The primary endpoint was the change from baseline in the Total IBS Symptom Score (TISS) after 4 weeks of treatment.
Results: Seventy-two patients (mean age 40.7 years, 75 % female, 77.8 % white) were randomized to PO (n = 35) or placebo (n = 37). At 4 weeks, PO was associated with a 40 % reduction in the TISS from baseline (mean change -1.16, SD ± 0.807), superior to the 24.3 % decrease (mean change -0.70, SD ± 0.737) observed with placebo (P = 0.0246). The decrease in the TISS of 19.6 % (mean change -0.55, SD ± 0.613) in the PO group at 24 h was also significantly larger than placebo (-10.3 %, mean change -0.27, SD ± 0.342) (P = 0.0092). At trial completion, patients in the PO group experienced greater improvement in multiple individual gastrointestinal symptoms as well as in severe or unbearable symptoms, compared to placebo. PO was well tolerated with few adverse events.
Conclusions: A novel PO formulation designed for sustained release in the small intestine is a safe, effective treatment capable of providing rapid relief of IBS symptoms.
Keywords: Abdominal pain; Bloating; Diarrhea; Irritable bowel syndrome; L-menthol; Peppermint oil.