New directions in the irritable bowel syndrome

The irritable bowel syndrome (IBS) is an umbrella for the diagnosis of heterogeneous conditions that are awaiting better identification of specific manometric causes. This article focuses on the concept that future therapy for IBS will rely on identification of subgroups and in turn tailor the specific therapeutic approaches to an appreciation of the pathophysiology and symptom predominance of these subgroups. Future therapies will rely on the following principles: (1) prokinetic agents to coordinate upper gastrointestinal and colonic motility as well as improve the propulsive nature of colonic contractions; (2) gastrointestinal hormone agonists such as erythromycin and antagonists such as sandostatin and cholecystokinin antagonists; (3) spasmolytic therapy incorporating calcium channel blocking and anticholinergic agents; (4) inhibition of ovulatory cycle changes in circulating concentrations of gonadal hormones in women, who tend to dominate the IBS population; (5) incorporation of concepts relating to the role of subtypes of 5-hydroxytryptamine receptors in control of neural and myogenic function; (6) reassessment of food intolerance and sensitivity; and (7) incorporation of concepts relating to psychologic profiles and psychologic treatment approaches. IBS is a rich and fertile area for application of the exciting new pharmacologic advances relating to gastrointestinal smooth-muscle and neural innervation of the gut. Improvement in the understanding and treatment of IBS will be one of the major accomplishments of this decade.