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

West Penn Allegheny Health System17 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

Purpose

TREATMENT

Masking

SINGLE

Enrollment

Conditions

Irritable Bowel Syndrome Generalized Anxiety Disorder

Interventions

DuloxetineDRUG

All subjects will receive single-blind placebo for the first two weeks, and then duloxetine for the next 12 weeks, followed by an up to 2 week taper off of the duloxetine. After 2 weeks of placebo daily, subjects will receive 30 mg per day of duloxetine for two weeks, then titrated up to 60 mg per day of duloxetine at week 2. A dosage decrease to 30 mg daily is permittable after week 2. This will be a flexible dose study with doses of duloxetine progressively increasing at weeks 4 (90 mg daily) and 6 (120 mg daily) in conjunction with CGI-I scores, to reach 120 mg daily or the maximum tolerated dose, if less than 120 mg daily at Week 12. There will be a post-taper follow up appointment at Week 14. Of Note: Amendment IRB Approved 6/14/11 Study Ending at Week 12 with removal of Week 14 visit as part of study.

Eligibility

Sex: ALLMin age: 18 YearsMax age: 65 Years

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

Clinical Global Impression Scale

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."

Time frame: endpoint [12 weeks]

Secondary Outcomes

Hamilton Anxiety Rating Scale

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.

Time frame: endpoint [12 weeks]

Irritable Bowel Syndrome-Quality of Life Scale

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.

Time frame: endpoint [12 weeks]

Irritable Bowel Syndrome Severity Scoring System

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.

Time frame: endpoint [12 weeks]

Data from ClinicalTrials.gov

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