[Effect of antacids on intestinal motility].

Disturbances of gut motility occur frequently under a highdose antacid regimen. Typical symptoms are diarrhea and constipation. They are due to the cations of the antacids. Aluminum causes constipation, magnesium induces diarrhea, and calcium has no definite motor effect. The following mechanisms of action have to be taken into consideration: effects of the cations on the smooth muscle of the gut, on the enteric nervous system and on the release of gastrointestinal hormones as well as alterations of the physiochemical properties of the intraluminal contents. Aluminum inhibits the motor activity of the stomach and intestine, magnesium stimulates muscle contractions; however, the simultaneous activation of the intrinsic nerves, which are predominantly inhibitory, by magnesium may conceal the muscular effects of this cation. The diarrhea under a highdose regimen of antacid combinations appears to be due predominantly to the osmotic-secretory effects of the antacids.