Citalopram of modest benefit for IBS

Clinical Question

Does citalopram improve symptoms in patients with irritable bowel syndrome?

Bottom Line

Citalopram in a dose of 20 mg daily for 3 weeks (perhaps increasing to 40 mg at that time) modestly improves symptoms in patients with irritable bowel syndrome (IBS). Paroxetine showed a similar benefit in a previous study, so this is likely a class effect of serotonin specific reuptake inhibitors (SSRIs). (LOE = 1b)


Tack J, Broekaert D, Fischler B, Oudenhove LV, Gevers AM, Janssens J. A controlled crossover study of the selective serotonin reuptake inhibitor citalopram in irritable bowel syndrome. Gut 2006;55:1095-1103.  [PMID:16401691]

Study Design

Cross-over trial (randomized)


Unknown/not stated




Outpatient (specialty)


Because tricyclic antidepressants have demonstrated efficacy in IBS, and because serotonin receptors are involved in colonic motor pathways, physicians are starting to try SSRIs for their patients with IBS. A total of 22 patients meeting the Rome II criteria for IBS entered this crossover study. Their mean age was 39 years and 18 were women. After a 2-week washout period during which none of the participants received any medications, researchers measured their baseline symptoms (abdominal pain, bloating, stool pattern abnormalities, and overall symptom severity) using a 10-cm visual scale. Half then received citalopram (Celexa) 20 mg per day for 3 weeks, followed by citalopram 40 mg per day for 3 more weeks. Symptoms were measured by telephone at 3 weeks and 6 weeks. The other half received placebo. After a 3-week washout period, those in the placebo group received citalopram and vice versa, again with symptom measurement at 3 weeks and 6 weeks. Patients also kept a daily symptom diary. This was a well-designed crossover study, and although small, the fact that each patient served as her or his own control gives it adequate statistical power to detect a clinically meaningful difference. At the end of the study, the severity of abdominal pain, bloating, stool abnormalities, and global symptoms while taking citalopram improved by approximately 2 points more than while taking placebo on the 10-point visual scale. This is a clinically significant difference (although just barely). Because of the obvious carryover effect observed in the study, a separate analysis of the first 6 weeks as a double-blind parallel arm was performed. The benefit of citalopram over placebo was confirmed. It is not clear whether patients required the increase to 40 mg, since there was no direct comparison between 20 mg for 6 weeks and 40 mg for 6 weeks.