Effect of STW 5-II (Iberogast-N) on Tolerance to Gastric Gas in Patients With Functional Dyspepsia. The IBO-2 Study

STW 5-II has been shown to improve numerous symptoms in functional dyspepsia.

To determine if the herbal medicinal product STW 5-II may improve gastric gas transit and tolerance in patients with functional dyspepsia.

In a parallel, randomized, double-blinded, placebo-controlled study, a gas challenge test was performed in 32 patients with functional dyspepsia and bloating after 2 weeks of treatment with (a) STW 5-II and (b) placebo. The challenge test consisted of continuous infusion of gas into the stomach (100 mL/min for 15 min) with simultaneous nutrient perfusion (315 kcal for 15 min, 210 mL final volume). Gas evacuation, symptom perception, and abdominal distension were continuously registered for 90 min.

Gastric gas infusion was followed by a progressive start of gas evacuation from the rectum that was significantly accelerated when patients were on STW 5-II (319 ± 81 mL after 20 min infusion start), compared to placebo (80 ± 39 mL; p = 0.015), but this difference declined during the following 90 min of gas evacuation (final gas retention 470 ± 160 and 662 ± 179, STW 5-II and placebo, respectively, p = 0.431). Gas infusion was associated with a significant rise and posterior progressive decline in abdominal symptom perception (mainly bloating) that was significantly lower in patients treated with STW 5-II (mean score increment 0.8 ± 0.4) than in patients treated with placebo (score increment 2.1 ± 0.4; p = 0.036). There were no significant differences in abdominal distension between groups.

STW 5-II improves tolerance to gastric gas in patients with functional dyspepsia and may be beneficial for the treatment of gas-related abdominal symptoms like bloating.

EudraCT number: 2019-003976-38.