The effect of omeprazole on insulin induced gastric secretion in man

The effect of oral omeprazole on insulin induced gastric secretion was studied in 12 healthy subjects. Each subject participated in two secretory tests receiving an intravenous infusion of insulin (0.03 units/kg/h) and being randomly allocated to receive 30mg or 60mg omeprazole suspended in 100ml water containing 16 mmol NaHCO3 on the second study day. Peak plasma concentrations of omeprazole were achieved within 30 minutes of administration in all but one subject and plasma half life was 30 minutes. Mean peak stimulated acid output in the six subjects receiving 30mg omeprazole was reduced to 4.3 +/- S.E. 1.8 mmol/h from a control value of 16.8 +/- 2.2 mmol/h (p less than 0.05) and in six subjects receiving 60mg omeprazole, mean peak output fell to 3.4 +/- 2.1 mmol/h from a control value of 12.3 +/- 2.6 mmol/h (p less than 0.05). The two doses of omeprazole produced similar reduction in acid secretion (74% and 73% respectively) but neither dose affected pepsin secretion. Both doses of omeprazole were associated with a small statistically insignificant increase in the plasma gastrin response to insulin infusion.