Effect of cimetidine on gastric secretion and duodenogastric reflux

In 19 subjects (four controls, one gastric ulcer and 14 duodenal ulcer) maximal gastric secretion was evoked with histamine 0.13 mumol/kg/h (0.04 mg/kg/h) for two to two and a half hours. A slow intravenous bolus dose of 200 mg cimetidine was given at the beginning of the last hour. Gastric secretion was measured before and after cimetidine administration and expressed both as mean acid output (mmol H+/h) and 'pyloric loss and duodenogastric reflux corrected' volume (Vg, ml/h). Mean reduction by acid output was 86%; mean reduction by corrected volume (Vg) was only 64%. The discrepancy, which is significant (p less than 0.01), is caused by a marked increase in duodenogastric reflux after cimetidine.