Dose-response study of omeprazole on meal-stimulated gastric acid secretion and gastrin release

In a placebo-controlled, double-blind, crossover, and randomized trial, the effect of 30, 60, and 90 mg of oral omeprazole on peptone-stimulated gastric acid secretion and synchronously measured gastrin release was studied in 8 healthy subjects. Peptone-stimulated acid output was reduced dose-dependently by 42%, 80%, and 92%, respectively. In spite of a short mean plasma half-life of 52 min, the inhibitory effect lasted for greater than 4.5 h and was significantly correlated to the area under the plasma concentration time curve for omeprazole. Mean basal serum gastrin and gastrin profiles increased insignificantly without alteration of integrated gastrin output and did not show any correlation either to the omeprazole area under the plasma concentration time curve or to the inhibition of peptone-stimulated acid secretion. Side effects, significant alterations of laboratory screen, or alterations of serum concentrations of thyroid hormones were not detected. In conclusion, omeprazole is a potent and, under the conditions tested, well-tolerated inhibitor of meal-stimulated gastric acid secretion in humans.