Paroxetine in Patients With Irritable Bowel Syndrome: A Pilot Open-Label Study

Background: Irritable bowel syndrome (IBS) is a common disorder and is the largest diagnostic cohort seen by gastroenterologists. There is a bidirectional comorbidity of IBS and psychiatric illness. Ours is the first study to examine the effect of any selective serotonin reuptake inhibitor in subjects with IBS.

Method: Twenty subjects with Rome I criteria-diagnosed IBS were treated with 20 to 40 mg of paroxetine for 12 weeks. We utilized a computer-administered patient daily questionnaire taken by patients over the telephone using an interactive voice response system.

Results: Sixty-five percent of patients (13/20) reported a reduction in abdominal pain, and 55% (11/20) reported a reduction in pain frequency (total or mean number of days per week in which the patient had the symptom decreased by 50%). Constipation and diarrhea were reduced in 69% and 57% of patients (9/13 and 8/14), respectively. Similarly, a clinically significant reduction in the symptoms of feeling of incomplete emptying (53% [9/17]) and bloating/abdominal distension (55% [11/20]) was apparent at study conclusion compared with baseline. On the Clinical Global Impressions scale at week 12, 47% (8/17) of the patients were much or very much improved.

Conclusion: In our pilot open-label study, paroxetine was very effective in alleviating the abdominal pain and associated symptoms of IBS. These results warrant further examination in a placebo-controlled study.