The purpose of the study is to determine the efficacy and safety of Rezular (arverapamil) in the treatment of IBS-D.

We have fulfilled our enrollment requirements for this study.

This study has been designed as a multicenter, randomized, double-blind, placebo controlled parallel dose group trial. The study will be open to both women and men. At screening the patient will be assessed to see if they meet the Rome III criteria for IBS-D. After screening, patients will undergo a 14-day run-in period evaluation, during which eligibility to be randomized to drug or placebo will be determined. Patients will complete daily telephone diaries during the run-in and double-blind phases of the study. Patients will be evaluated at regularly scheduled clinic visits during double-blind phase of the study.

Patients who complete the study may have the opportunity to rollover to the open-label one-year safety study (ARDIS-3).

Inclusion Criteria:

• fulfilling Rome III criteria for IBS-D

Exclusion Criteria:

• major cardiovascular disease
• psychiatric illness except mild or moderate depression
• pregnancy
• presence of other GI disease that could explain IBS-like symptoms
• history of major gastric, hepatic, pancreatic or intestinal surgery or perforation