Chronic constipation: Mechanisms of action and effective treatment

This is an exciting time in the treatment of functional gastrointestinal (GI) disorders because of our rapidly evolving understanding of the mechanism of action of these illnesses and their treatment. In this article, chronic constipation (CC), which is one of the most common functional disorders of the gut, is discussed. Although not life-threatening, CC can profoundly and negatively affect quality of life and is associated with a significant economic burden of direct and indirect annual healthcare costs. In the United States alone, estimates from several years ago placed the annual cost of laxatives to treat constipation at $800 million. Possible causes of CC range from psychologic disorders to dysfunctions of GI motility, though most patients do not have an identifiable explanation for their constipation. Recent research indicates that constipation most likely results from abnormalities of myenteric neurons or pacemaker function, defects in neurotransmitters, or incoordination of the muscles of the pelvic floor or anorectum, and may be influenced by environmental factors or chronic stress. In this article, the symptoms of CC are reviewed and the safety and efficacy of traditional, novel, and emerging therapies are examined. Because of the overlap in symptoms, many of the treatments discussed in this review also apply to patients with constipation-predominant irritable bowel syndrome.