5-PATHOGENESIS
PPIs include omeprazole, pantoprazole, esomeprazole, lansoprazole, rabeprazole, and the newer dexlansoprazole and tenatoprazole. They have a common chemical structure, represented by a benzimidazole ring plus a pyridine ring, varying only in the side chain substituted on both moieties. Omeprazole and pantoprazole have, respectively, a methoxy and a difluoromethoxy chain in their benzimidazole rings, whereas lansoprazole and rabeprazole modify the pyridine ring where the trifluoroethoxy and methoxypropoxy chains are located respectively. Tenatoprazole is the only one with an imidazopyridine, instead of a benzimidazole, ring structure, responsible for a longer half-life of the drug compared to other PPIs.2,32,33