Peppermint Oil for the Treatment of Irritable Bowel Syndrome or Functional Abdominal Pain in Children: the MINT Study

Inclusion Criteria:

• Children aged between 8 years and 18 years
• Diagnosis of IBS or FAP-NOS according to the Rome IV criteria. According to thesecriteria, organic disorders will be ruled out after routine laboratory testinginitiated by their general practitioner or treating physician as part of standard ofcare. In patients without alarm symptoms only celiac screening (anti-transglutaminaseantibodies and IgA), and faecal calprotectin are necessary.37 In patients withdiarrhea faecal testing for Giardia Lambliae will be added. If alarm symptoms arepresent, further diagnostic testing (like a full blood count, CRP, liver tests or anultrasound) to rule out an organic disorder, is left to the discretion of the treatingphysician.
• An average daily pain rate of ≥ 3 of 10 on the Wong Baker Faces Pain Scale (This is avalidated pain scale to measure pain intensity). Informed Consent by both parents and by children aged ≥ 12 years. No informed consent fromparents is necessary for children >16 years.

Exclusion Criteria:

• Current treatment by another health care professional for abdominal symptoms
• Previous use of peppermint oil for these abdominal complaints
• Known hypersensitivity to mints or peppermint oil
• Gastrointestinal blood loss
• Recurrent or unexplained fevers
• Decreased growth velocity
• History of previous abdominal surgeries in the past 3 months
• Significant chronic health condition requiring specialty care (e.g., lithiasis,ureteropelvic junction obstruction, sickle cell, cerebral palsy, hepatic,hematopoietic, renal, endocrine, or metabolic diseases) that could potentially impactthe child's ability to participate or confound the results of the study
• Known concomitant organic gastrointestinal disease
• Current use of drugs which influence gastrointestinal motility, such as erythromycin,azithromycin, butyl scopolamine, domperidone, mebeverine and Iberogast. If laxativesare being used (in patients with IBS-C) they can continue using them during the study.
• Current use of proton-pump inhibitors
• Insufficient knowledge of the Dutch language
• Pregnancy or current lactation. Women with childbearing potential must have a negativeurine pregnancy test within 7 days prior to first dose of study treatment