Effect of cimetidine on the human lower oesophageal sphincter.

Lower oesophageal sphincter pressures in healthy volunteers were measured by a rapid pull-through technique during intravenous infusion of the histamine H2-receptor antagonist, cimetidine. No consistent effects on sphincter pressure were observed which are liable to be of clinical importance. Serum gastrin concentrations during cimetidine infusion were measured by radioimmunoassay and showed no significant variation. In a further series of experiments, the response of the lower oesophageal sphincter to intravenous bolus injection of pentagastrin was measured before and during cimetidine infusion. Cimetidine infusion had no significant effect on the sphincter response to pentagastrin.