Newer pharmacologic agents that mediate neurotransmitter activity may prove useful in the treatment of irritable bowel syndrome.
Irritable bowel syndrome (IBS) is a chronic disorder characterized by recurrent symptoms of lower abdominal pain with disturbed defecation and bloating. The disorder affects up to 20% of the population and is the most common gastrointestinal (GI) ailment diagnosed by general practitioners. Although it is estimated that only one in five patients with IBS seeks medical attention, direct medical costs account for an estimated $8 billion each year within the United States. While the syndrome is not believed to increase mortality or predispose patients to serious complications, it does significantly affect quality of life and has been identified as the second leading cause of absenteeism from work or school.
The pathophysiology of irritable bowel syndrome (IBS) is not fully understood. However, it is thought to be related to abnormal intestinal motility, enhanced pain sensitivity, and increased autonomic reactivity mediated by interactions between the central nervous system (CNS) and the enteric nervous system (ENS). As a functional disorder, structural or biochemical abnormalities are not evident and the diagnosis is based upon clinical presentation of patient symptoms. Management of IBS involves patient education, dietary and lifestyle changes, and pharmacologic therapy based on dominant symptoms. Although successful drug treatment for IBS has been limited, newer pharmacologic agents that mediate neurotransmitter activity may prove useful. The goal of this article is to provide the pharmacist with current information about the epidemiology, pathophysiology, clinical presentation, and treatment of irritable bowel syndrome (IBS).
An estimated 35 million Americans suffer from irritable bowel syndrome (IBS) and up to 75% of these patients are female. Two possible reasons for the gender disparity are that IBS has a hormonal etiology — since IBS symptoms appear to coincide with menses and pregnancy — and/or that women are more likely to seek medical care. IBS accounts for 12% of primary care visits and between 20% and 50% of gastroenterology consultations, resulting in an estimated 3.5 million physician visits per year in the U.S. This is second in number only to physician appointments for the common cold. Patients with higher education, high income levels, and a greater perceived intensity of pain and stress are most likely to pursue medical care for irritable bowel syndrome (IBS).
Irritable bowel syndrome (IBS) has a significant impact on the utilization of healthcare resources and quality of life. Patients with IBS symptoms miss three times as many workdays as do healthy individuals. In a study of undergraduate students diagnosed with IBS, impairment on indices of quality of life was greater than in patients with congestive heart failure. The irritable bowel syndrome (IBS) in American Women Survey revealed that IBS symptoms forced women to miss work, limit travel, and avoid outings. Of interest, more than 60% of the women interviewed expressed that they organized their schedule based on the location of restrooms. Patients with IBS commonly suffer from comorbid conditions, including fibromyalgia, chronic fatigue syndrome, dysmenorrhea, depression, anxiety, urinary problems, and other abdominal disorders. In addition, women diagnosed with irritable bowel syndrome (IBS) report having nearly twice as many abdominal or intestinal surgeries as women without the disorder.