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

Phase 4

Completed

Brief Summary: 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.

Detailed Description: 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.

Recruitment & Eligibility

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

Arm && Interventions

Group	Intervention	Description
Duloxetine	Duloxetine	Two weeks of placebo run in followed by 12 weeks of Duloxetine.

Primary Outcome Measures

Name	Time	Method
Clinical Global Impression Scale	endpoint [12 weeks]	The scale consists of two parts the first part being Severity of Illness and the second part is Global Improvement. We report the Global improvement scale. The Global Improvement is a 1-7 change scale of global improvement since inclusion in the project ranging with 1 "very much improved", 4 "no change", and 7 "very much worse."

Secondary Outcome Measures

Name	Time	Method
Irritable Bowel Syndrome-Quality of Life Scale	endpoint [12 weeks]	The IBS-QOL consists of 34 items, each with a five-point response scale. Ratings range from 1 "not at all" to 5 "extremely" or "a great deal" Higher responses on the scale indicate worse outcome. A minimal total score would be 34, maximum 170.
Hamilton Anxiety Rating Scale	endpoint [12 weeks]	The HAM-A is a 14 question scale with five responses. Responses range from 0 "not present" to 4 "very severe." The total score ranges from 0 to 56. Higher values represent a worse outcome.
Irritable Bowel Syndrome Severity Scoring System	endpoint [12 weeks]	This is a 4 item Likert scale with each assessment being 100 mm scored from measuring from 0 to 400. Higher numbers indicate worse outcome.