<P> PPIs have a half - life in human blood plasma of only 60--90 minutes, but because they covalently bind to the pump, the half - life of their inhibition of gastric acid secretion lasts an estimated 24 hours . Dissociation of the inhibitory complex is probably due to the effect of the endogenous antioxidant glutathione which leads to the release of omeprazole sulfide and reactivation of the enzyme . </P> <P> Medically used proton pump inhibitors: </P> <Ul> <Li> Omeprazole (OTC in the USA) </Li> <Li> Lansoprazole </Li> <Li> Dexlansoprazole </Li> <Li> Esomeprazole </Li> <Li> Pantoprazole </Li> <Li> Rabeprazole </Li> <Li> Ilaprazole (not FDA approved as of May 2017) </Li> </Ul> <Li> Omeprazole (OTC in the USA) </Li>

The most effective inhibitor of human gastric acid secretion is