Abstract
BACKGROUND: Selective norepinephrine-serotonin receptor inhibitors (SNRIs) such as duloxetine have already shown beneficial effects on symptoms in irritable bowel syndrome (IBS) patients. The purpose of the present investigation was to assess the efficacy of duloxetine in the symptom and quality of life improvement in diarrhea predominant-IBS (IBS-D) patients. MATERIALS AND METHODS: IN a randomized, double-blind and placebo-controlled study, sixty patients diagnosed with IBS-D (ROM-IV criteria), referred to the gastrointestinal clinic of Rasoul-e-Akram Hospital of Iran university of medical sciences, randomly assigned in the treatment groups, group A: patients who received 135 mg mebeverine tablet twice a day combined with 30 mg duloxetine capsule per day and group B, who received the same regimen, except for placebo capsule once per day instead of duloxetine for twelve weeks. The assessment was performed using the IBS severity index, and IBS quality of life questionnaire (IBS-QOF) at baseline, and weeks 4, 8, and 12 after beginning the treatment. Drug adverse effects and compliance to treatment were evaluated every 2 weeks after starting the treatment. RESULTS: Sixty patients completed the trial. The duloxetine group showed significantly greater improvement on the IBS symptoms (P < 0.001), and the IBS-QOF (P < 0.001) in comparison to the placebo group at the endpoint. CONCLUSIONS: This study showed that adding duloxetine to mebeverine is safe with good efficacy on symptoms and QOL improvement in IBS-D patients. Besides, this study showed that 12 weeks' treatment duration is significantly more effective than 4 weeks' treatment, and drug adverse effects are more prominently seen in the first 2 weeks of treatment.