Upper gastrointestinal promotility drugs: not all uniform?

Abstract

The pathophysiology of functional gastrointestinal (GI) disorders has been under broad investigation in the past two decades; dysmotility remains one of the main focuses of the research. Numerous studies have documented abnormal gastroduodenal motility in patients with functional dyspepsia, irritable bowel syndrome, and other functional GI disorders. In functional dyspepsia, the abnormalities range from delayed to accelerated gastric emptying, abnormal antral and fundic contractions, and disordered accommodation in the fundus and antrum. Some of the functional GI symptoms may be explained by disturbed motility both during and after the meal. Less is known about small bowel dysmotility. Alterations in small bowel transit time, proximal small bowel accommodation, and abnormal contractions may play a role in pathophysiology of symptoms of the functional disorders. Currently, we have witnessed rapidly accumulating knowledge about the functional characteristics of GI tract motility. Some new tools are available such as a wireless motility capsule 1 or impedance pH test. These tests can give additional information about the relationships between GI transit and contractility as measured by manometry. But antroduodenal manometry, though uncommonly performed, still provide fascinating insights into upper GI motility. Using promotility agents to treat functional GI disorders is very attractive, given that they may target some of the underlining pathophysiologic mechanisms. Unfortunately, most of them are only modestly effective. This may be due to the fact that normal gut motility is a complex interaction between multiple neurotransmitters, while available drugs usually target only one neurotransmitter or receptor involved in the maintaining of normal GI motility function.