The effect of Iberogast on heartburn in patients with indigestion

Rationale: Iberogast (STW5) is a multitarget herbal preparation which has been shown to effectively reduce symptoms in patients with functional dyspepsia. Many patients have, in addition to functional dyspepsia, heartburn complaints. Thus far, the mechanism of action of Iberogast in heartburn reduction is unknown. It has been demonstrated that the incidence of gastro-oesophageal reflux episodes is influenced by gastric motility and emptying. Since Iberogast affects proximal gastric motility, Iberogast could, in theory, result in a reduced incidence of reflux episodes in patients with dyspepsia. It is also possible that Iberogast could reduce the sensitivity of the oesophagus and stomach, and thus reduce perception of the refluxate. Given that the effect of proton pump inhibitors in dyspepsia with heartburn is small and the alternative treatment options are limited, a positive result could have a major effect on the treatment of heartburn in this patient population.

Objective: To assess the effect of Iberogast on heartburn, the incidence of reflux episodes and oesophageal sensitivity in patients with functional dyspepsia.

Study design: A prospective phase III study with a double blind placebo-controlled, randomized cross-over design.

Study population: Eighteen patients (> 18 years of age) with a history of dyspepsia and heartburn and a negative upper GI endoscopy will be invited to participate.

Intervention (if applicable): All patients will receive in one period either a placebo or Iberogast (20 drops three times daily) for at least 4 weeks, followed by a second period in which they will receive the other study medication (placebo if they received Iberogast during the first period and Iberogast if they received placebo during the first period).

Main study parameters/endpoints: The main study parameter is the GORD symptom score improvement based on the RDQ Questionnaire score. Secondary endpoints are a decrease in reflux (measured with 24-hour oesophageal pH-impedance monitoring) and a decrease in oesophageal acid perception (acid perfusion test).

Nature and extent of the burden and risks associated with participation, benefit and group relatedness: The subjects will have a total of 5 visits and will have to fill out 2 questionnaires on three separate occasions. There are no risks involved with oesophageal acid perfusion or with the 24-hour pH-impedance measurement. Both tests are only associated with discomfort in nose and throat upon placement of the catheter and with mild discomfort if the acid is perceived. Participants will be compensated financially for participation in the study and the findings could help treat future patients with similar complaints.

We hypothesize that Iberogast reduces heartburn in patients with functional dyspepsia through an effect on both oesophageal hypersensitivity to acid and on the incidence of reflux episodes.

Day 1, 4 weeks, 4 week 1 day, 8 weeks, 8 week 1 day

All patients will receive in one period either a placebo or Iberogast (STW5) (20 drops three times daily) for at least 4 weeks, followed by a second period in which they will receive the other study medication (placebo if they received Iberogast during the first period and Iberogast if they received placebo during the first period).