Pharmacology: Omeprazole markedly inhibits basal and stimulated gastric acid secretion. It has a unique mode of action, irreversibly blocking the proton-pump of the parietal cells which is supposedly the terminal step in the acid secretory pathway.
Pharmacokinetics: Omeprazole is rapidly absorbed after release from enteric-coated formulations. Peak plasma concentration of omeprazole occurs after 3-4 or 5-6 hrs following oral administration. The mean half-life is 0.5-1.5 hrs. Omeprazole is eliminated rapidly and almost completely by metabolism. Three metabolites observed in plasma are sulfide and sulfone derivatives of omeprazole and hydroxyomeprazole. These metabolites have very little or no antisecretory activity.