Selective serotonin reuptake inhibitors (SSRIs) are frequently used for irritable bowel syndrome, while duloxetine was evaluated in other similar psycho-somatic syndromes.

This prospective, single-blind trial intends to compare the efficacy of SSRIs and duloxetine in the treatment of irritable bowel syndrome.

A group of 22 patients, 15 female and 7 male, mean age 50.2, diagnosed with irritable bowel syndrome according to the Rome II Diagnostic Criteria (1992) were treated with either an SSRI (escitalopram 20 mg/day, n = 6 or fluoxetine 40 mg/day, n = 6) or duloxetine (90 mg/day, n = 10). Patients were evaluated initially and every 4 weeks, for 6 months, using Hamilton Anxiety Rating Scale (HAMA), Hamilton Depression Rating Scale 17 items version (HAMD), Clinical Global Impressions -Severity/Improvement (CGI-I/S) and a 7-points Likert scale (LS) for self-evaluated severity.

Duloxetine improved anxiety and depressive symptoms, as reflected by the significant decrease of HAMA (−17.6 points, p < 0.05) and HAMD scores (−18.2 points, p < 0.05) at week 12. SSRIs also reduced the affective symptoms, significantly to baseline (p < 0.05), but less than duloxetine (−14.3, −15.2) at week 12, with no significant difference at week 24 (p = 0.120). The CGI-I results paralleled the decrease of HAMD and HAMA, while the LS evaluation of gastrointestinal symptoms improved similarly in both groups, with no significant difference (p = 0.09).

Duloxetine is an efficient agent in the treatment of irritable bowel syndrome, because it decreases the mood symptoms more rapidly than SSRIs. The overall efficacy of SSRIs and duloxetine at 6 months is nevertheless similar.