Paroxetine to treat irritable bowel syndrome not responding to high-fiber diet: a double-blind, placebo-controlled trial

Am J Gastroenterol. 2004 May;99(5):914-20. doi: 10.1111/j.1572-0241.2004.04127.x.


Objectives: The purpose of the trial was to determine whether a high-fiber diet (HFD) alone or in combination with paroxetine or placebo was effective treatment for patients with irritable bowel syndrome (IBS).

Design: Trial of HFD alone (Group 1) followed by a randomized, double-blind trial of HFD with paroxetine or placebo (Group 2).

Setting: Gastroenterology office in a 524-bed university-affiliated community hospital in Pittsburgh.

Patients: Men and women, aged 18-65 yr, previously diagnosed with IBS but otherwise healthy.

Intervention: Institution of HFD in 98 participants consuming low- or average-fiber diets. Allocation of paroxetine to 38 and placebo to 43 symptomatic participants consuming HFDs.

Measurements: Overall well-being, abdominal pain, and abdominal bloating (Groups 1 and 2); food avoidance, work functioning, and social functioning (Group 2).

Results: In Group 1, overall well-being improved in 26% patients, and abdominal pain and bloating decreased in 22% and 26% patients, respectively, with an HFD. In Group 2, overall well-being improved more with paroxetine than with placebo (63.3%vs 26.3%; p= 0.01), but abdominal pain, bloating, and social functioning did not. With paroxetine, food avoidance decreased (p= 0.03) and work functioning was marginally better (p= 0.08). Before unblinding, more paroxetine recipients than placebo recipients wanted to continue their study medication (84%vs 37%; p < 0.001).

Conclusions: The difference in overall well-being found in our paroxetine/placebo trial is greater than that found in previously published drug/placebo trials for IBS. Moreover, the difference in well-being applied to nondepressed recipients of paroxetine.

Publication types

  • Clinical Trial
  • Comparative Study
  • Randomized Controlled Trial
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adolescent
  • Adult
  • Aged
  • Dietary Fiber / adverse effects
  • Dose-Response Relationship, Drug
  • Double-Blind Method
  • Drug Administration Schedule
  • Female
  • Follow-Up Studies
  • Humans
  • Irritable Bowel Syndrome / diagnosis*
  • Irritable Bowel Syndrome / drug therapy*
  • Male
  • Middle Aged
  • Paroxetine / administration & dosage*
  • Probability
  • Reference Values
  • Risk Assessment
  • Serotonin Uptake Inhibitors / administration & dosage*
  • Treatment Outcome


  • Dietary Fiber
  • Serotonin Uptake Inhibitors
  • Paroxetine