An Open Label Trial of Duloxetine in the Treatment of Irritable Bowel Syndrome and Comorbid Generalized Anxiety Disorder

An Open Label Trial of Duloxetine in the Treatment of Irritable Bowel Syndrome and Comorbid Generalized Anxiety Disorder

The investigators propose to evaluate the effectiveness of duloxetine in treating subjects with both Irritable Bowel Syndrome (IBS) and Generalized Anxiety Disorder (GAD). The investigators hypothesize that duloxetine as a single therapeutic agent will effectively target pain and other core symptoms of IBS as well as GAD in this patient population with both conditions.

Generalized Anxiety Disorder (GAD) is commonly associated with Irritable Bowel Syndrome(IBS). The etiology of IBS remains unknown and it is often refractory to treatment. Duloxetine has demonstrated efficacy in the treatment of GAD as well as other pain disorders including fibromyalgia and diabetic neuropathy.

We plan to study 30 subjects with diagnoses of IBS and GAD between the ages of 18 and 65 years. There will be a single-blind placebo-run-in for the first 2 weeks, followed by open-label duloxetine for 12 weeks flexibly titrated to 120 mg/day. Subjects will be informed that they will receive placebo for 2 weeks during the trial. All study visits will be at Allegheny General Hospital Department of Psychiatry. The study consists of a total of nine office visits.

Inclusion Criteria:

• 18-65 years of age
• Active IBS diagnosis by a gastroenterologist
• Generalized Anxiety Disorder diagnosed by DSM-IV TR criteria and the Mini International Neuropsychiatric Interview for the DSM-IV (Mini)
• No changes in any non study medication once starting the study

Exclusion Criteria:

• Current diagnoses of Major Depressive Disorder, Panic Disorder, Social Phobia, Post Traumatic Stress Disorder, Obsessive Compulsive Disorders, Eating Disorders, Somatoform Disorders, Drug or alcohol abuse or dependence, or severe personality disorder
• Lifetime history of any Bipolar Disorder or Psychotic Disorder
• Concurrent GI disorders falling outside of Rome III Functional GI disorders
• Pregnant women or sexually active female subjects not using medically acceptable method of contraception
• Current suicidal ideation
• Unstable medical condition