Effects of oral magnesium sulphate on colonic motility in patients with the irritable bowel syndrome

Abstract

Magnesium sulphate, a substance known to cause release of cholecystokinin (CCK) from the small intestinal mucosa, was given by mouth (dose 0.1 g/kg in 150 ml water) to 20 patients with the irritable bowel syndrome. A rapid increase in colonic segmental motor activity (onset within 2 to 6 min in most cases) was seen (percentage activity increased from 16.2 to 23.7 p<0.05; mean wave amplitude from 7.1 to 9.1 cm H2O, NS; motility index from 144 to 259, p<0.01). This increase was most marked in 10 patients who complained of attacks of abdominal pain after food (16.1 to 29.8%, p<0.01; 6.8 to 9.6 cm H2O, p<0.05; 135 to 350, p<0.05), and after the magnesium sulphate 3 of these patients experienced an attack of their usual pain. These findings provide further evidence that 'functional' abdominal pain after food may in some cases be related to an exaggerated intestinal motor response to cholecystokinin.