Effect of H2-receptor antagonists cimetidine and famotidine on interdigestive gastric motor activity and lower esophageal sphincter pressure in progressive systemic sclerosis.

The effect of the H2-receptor antagonists cimetidine and famotidine on interdigestive gastric motor activity and lower esophageal sphincter pressure was assessed in 41 patients with uncomplicated progressive systemic sclerosis. There was no significant change in gastric phasic motor activity after the intravenous administration of cimetidine (n = 6), famotidine (n = 13), and physiological saline (n = 15), or the intragastric infusion of 7% sodium bicarbonate (n = 7). The lower esophageal sphincter pressure was increased significantly by both cimetidine and famotidine, but only famotidine caused a significant pressure rise in patients without an increase of gastric motility. Cimetidine and physiological saline produced a similar pattern of change in the esophageal sphincter pressure, as did famotidine and sodium bicarbonate. These findings suggest that the inhibition of acetylcholinesterase activity and gastric acid secretion may be involved in the respective mechanisms of action of cimetidine and famotidine.