Background & Objective:  Irritable bowel syndrome (IBS) is a functional bowel disorder characterized by changes in bowel movements and abdominal pain in the absence of structural disorders. Although effective treatment for irritable bowel syndrome is not yet available. One of the treatments is the low-dose antidepressants, depending on the type and severity of the disease. This study was performed to compare the effect of selective serotonin-norepinephrine reuptake inhibitors including duloxetine and imipramine from a tricyclic antidepressant.
Materials & Methods: forty-eight definitively diagnosed IBS patients (based on Rome III criteria) were examined in 2 groups of men and women. Patients in the control group were treated with Dicyclomine and Imipramine while the case group received dicyclomine and duloxetine. The outcomes were measured before and 3 months after treatment to determine and compare the improvement in responses (mainly diarrhea).
Results: Duloxetine could significantly improve the symptoms such as abdominal pain in females (P-value: 0.01) and males (P-value: 0.001), bloating in females (P-value: 0.004) and incomplete defecation in females (P-value: 0.001) and in males (P-value: 0.007). The side effects of this drug were, however, higher than Imipramine. The introduction of more appropriate treatment requires further studies on a larger sample size to assess the symptoms and the side effects.
Conclusion: Based on the effect of duloxetine on this clinical results, it is recommended as an effective treatment in controlling of abdominal pain, bloating, and incomplete defecation.