The Pharmaceutical Journal
Vol 273 No 7321 p554
16 October 2004

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SSRIs provide modest benefit in selected IBS patients

POEM series

Clinical question Are selective serotonin reuptake inhibitors effective for the treatment of irritable bowel syndrome?

Bottom line Paroxetine in a dose of 10mg to 40mg per day provides at least a small benefit in terms of overall well-being for patients with irritable bowel syndrome who have already tried a high-fibre diet. We do not know the true magnitude of this benefit because of the way the results are reported. We also do not know whether selective serotonin reuptake inhibitors are more effective than tricyclic antidepressants.

Synopsis Although tricyclic antidepressants are somewhat effective for irritable bowel syndrome (IBS), it is less clear whether selective serotonin reuptake inhibitors (SSRIs) are similarly helpful. Patients for this study came from two groups: (1) patients presenting to the gastroenterologist on a low-fibre diet who did not improve on a high-fibre diet; and (2) patients presenting for care who were already eating a high-fibre diet. They were randomised to either placebo (n=43) or paroxetine 10mg per day, increasing the dose to 20mg or 40mg per day if there was no improvement at the lower dose (n=38). The mean age of patients was 46 years, 74 per cent were women, and most had diarrhoea-predominant IBS. Eight patients withdrew from the paroxetine group and seven withdrew from the placebo group; approximately half in each group because of perceived adverse drug effects. The primary outcome was overall well-being measured using a five-point scale, where an increase of 0.5 points equals a clinically significant improvement. A clinically significant improvement was reported by 63.3 per cent of patients receiving paroxetine compared with 26.3 per cent receiving placebo (P=0.01, number needed to treat [NNT] 2.7). The benefit was similar for the subset of patients with a Beck Depression Inventory score of less than 10. Although there was a small improvement in food avoidance for the patients taking paroxetine, there was no difference in work or social function. When patients were asked at the end of the 12-week study whether they wanted to continue the study medicine, 84 per cent in the paroxetine group said yes compared with only 37 per cent in the placebo group (P<0.001, NNT 2). The mean improvement in scores for well-being are not reported for the two groups, though.

Level of evidence 1b (individual randomised controlled trial with narrow confidence interval)

Reference Tabas G, Beaves M, Wang J, et al. Paroxetine to treat irritable bowel syndrome not responding to high-fiber diet: a double-blind, placebo-controlled trial. American Journal of Gastroenterology 2004;99:914–20.

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