Effect of cimetidine on lower esophageal sphincter pressure, intragastric pH and serum levels of immunoreactive gastrin in man.

The influence of cimetidine on the lower esophageal sphincter, the intragastric pH and the serum levels of immunoreactive gastrin was investigated in eight volunteers and compared with a control group. After oral application of 400 mg cimetidine, the intragastric pH rose from 1.7 +/- 0.13 to 6.2 +/- 0.4 and the lower esophageal sphincter pressure increased slightly but significantly from 15.6 +/- 1.1 to 22.7 +/- 1.8 mm Hg after 20 min and to 25.8 +/- 2.0 after 30 min, respectively. At the same time the serum immunoreactive gastrin levels did not change. A direct effect of cimetinidine on the lower esophageal sphincter or an indirect effect via gastric alkalinization is discussed.