Will controlled release mebeverine be able to surpass placebo in treatment of diarrhoea predominant irritable bowel syndrome?

Background and Aims: Irritable bowel syndrome (IBS) is a chronic relapsing disorder characterized by abdominal pain-discomfort and altered bowel habits. The IBS-diarrhoea predominant subtype (IBS-D) is defined as >25% of bowel movements representing type 6 or 7 of the Bristol Stool Form Scale. Management of IBS-D is mainly symptomatic, including lifestyle modification. Due to absence of standard treatment, multiple drugs are used. A controlled release (CR) form of mebeverine, recommended for spasmodic gastrointestinal disorders (including IBS) has recently been introduced in Indian market. We have conducted a placebo-controlled double blind randomized controlled trial [CTRI/2018/03/012897] to evaluate the effectiveness and safety of this product. Methods: 40 patients of IBS-D were recruited from medicine out-patient department (OPD) of a tertiary care hospital and randomized to two parallel groups. One received mebeverine 200 mg CR tablets twice daily for 8 weeks, while other received matching placebo. Outcome parameters were number of bowel movements per day over past 7 days (NoBM7d), severity of abdominal cramps and IBS quality of life (IBSQoL) score. Medication adherence record and treatment emergent adverse events were captured. Results: Mebeverine group showed modest but statistically significant improvement in NoBM7d, cramps and IBSQoL from baseline to 4 and 8 weeks. The changes within the placebo group were not statistically significant. Also, the intergroup differences at both 4 and 8 weeks were not statistically significant. Adherence was better in mebeverine group and both interventions were well tolerated. Conclusions: Mebeverine 200 mg CR twice daily has modest effect in IBS-D and therefore will not be a good choice for patients with severe symptoms.