[Therapeutic perspectives in the irritable bowel syndrome]

Future treatments of functional intestinal disorders (FID) are essentially dependent on the possible pathophysiologic hypotheses. Schematically, symptoms experienced by patients with FID can be attributed to intestinal (small or large intestine) motor disturbances or to visceral sensitivity derangement, which, in turn, may be primary or secondary to an anomalous response to alimentation, liberation of hormones or neuromediators, or to a "stress" situation. New therapeutic agents can be directed against the symptoms experienced by patients (? action on pain or intestinal transit disorders) or against the initial pathophysiologic mechanisms. In the treatment of functional diarrhea, several substances have been proposed recently. Encephalines are peptides with extremely short duration of action which are degraded by two membranous enzymes, encephalinase and carboxypeptidase. Recently, it has been shown that acetorphan, an inhibitor of encephalinase, is efficacious in acute diarrhea. Alpha-2-antagonists are substances which are capable of slowing intestinal transit time and increasing intestinal absorption. Their antidiarrheic action is moderate, and they do not act on abdominal pain. Molecules that do not traverse the neuromeningeal barrier but that act selectively on the digestive tract and are better tolerated are expected. In patients complaining of severe idiopathic constipation substances capable of stimulating colonic motility are useful: substance P or neurotensin analogues might prove interesting. Antagonists of opium receptors such as Naloxone have proved efficacious in the treatment of certain cases of chronic idiopathic intestinal pseudo-obstructions or severe constipation. The development of orally active substances or with hepatic elimination are a prerequisite. Therapy based on well characterized pathophysiologic abnormalities would be welcome.(ABSTRACT TRUNCATED AT 250 WORDS)