Effect of omeprazole on gastric acid secretion in rat: evaluation of dose, duration of effect, and route of administration

The effect of omeprazole on gastric acid output was studied in rats before and during stimulation by continuous administration of tetragastrin at 50 micrograms/kg-hour. From 5 to 20 mg/kg of omeprazole was given to animals intraperitoneally, perorally and intravenously from 2 to 24 hours before the gastric secretory study was started, and the respective effects on acid secretion were compared. In each administration group, 20 mg/kg of omeprazole was the most potent among the groups receiving 5, 10 or 20 mg/kg, when the drug was given 2 hours before the study. There were statistically significant differences between the control group given tetragastrin only and each of the groups given 20 mg/kg of omeprazole perorally, intraperitoneally and intravenously. There was no significant difference among the groups given 20 mg/kg of omeprazole intraperitoneally, intravenously and perorally. The effect of 20 mg/kg of omeprazole continued at least 24 hours after the agent was administered perorally.