In the last 3 years, after a pause of more than 25 years, functional GI disorders including IBS and functional dyspepsia have once again become the focus of intense research and new drug development. It may be predicted that more effective medications will be available for patients suffering from these disorders within the next 5 years.

A more comprehensive disease model which emphasizes an important role of the sensory innervation of the GI tract has resulted in the development and assessment of several different types of medications. Many of these new drugs undergo clinical testing in Europe first before coming to the U.S. for evaluation in so-called Phase II studies.

Visceral analgesics act on the nerve endings within the gut and generally do not reach the brain. They include 5HT3 receptor antagonists (blocking the effect of serotonin) and opioid agonists (mimicking the effect of the body’s own painkillers, the endorphins). Their main indication is abdominal pain and discomfort.

Antispasmodics interfere with the excessive contractions of the intestine, particularly the sigmoid colon, which commonly occur after food intake and during stress. The new compounds are more specific for the GI tract and lack the disturbing CNS side effects of older medications of the same type. Their main indication is abdominal pain and discomfort.

Prokinetics enhance propulsive activity of the colon. They restore the ability of the colon to transport its contents in a coordinated fashion from the cecum to the rectum. Their main indication is constipation.

Antidepressants have recently been developed which can affect both mood and pain perception in patients with depression and IBS.