OBJECTIVE

To investigate the efficacy and tolerability of octatropine methyl bromide plus diazepam (Valpinax) in patients with irritable bowel syndrome (IBS).

MATERIALS AND METHODS

We conducted a randomized, double-blind, multicentre study in 186 patients aged 18-65 years with IBS diagnosed according to Rome II criteria. Following a 2-week washout period, patients received octatropine plus diazepam 40 mg/2.5 mg twice daily or placebo for 6 weeks. The primary efficacy endpoint was response to a weekly question: "did you have satisfactory relief of your abdominal pain and discomfort during the last week?" Other endpoints included abdominal swelling, abdominal pain and discomfort, symptom severity, and the number of bowel movements. A prespecified subgroup analysis was conducted in patients with an abdominal pain and discomfort score > or = 3.

RESULTS

The primary efficacy endpoint showed a tendency towards a statistically significant benefit for octatropine plus diazepam over placebo among patients with a baseline abdominal pain and discomfort score of > or = 3 (3 vs. 0 patients; p = 0.059). Octatropine plus diazepam demonstrated significant improvements from baseline in all parameters assessed, but not compared with placebo. Adverse events were reported in 15.1% of patients receiving octatropine plus diazepam.

CONCLUSIONS

Patients with IBS and an abdominal pain and discomfort score of > or = 3, who may be considered in the active phase of the disease, may derive some benefits from octatropine plus diazepam. This study highlights that Rome II criteria should be considered with particular care in the design of a clinical trial, since it does not consider disease activity level on admission.