Esomeprazole is a proton pump inhibitor (PPI), a drug that is used to reduce acid secretion in the stomach. There are several different brand names for esomeprazole including Nexium, Essocam and Esmezol. The molecule is developed and marketed by AstraZeneca. Esomeprazole is the more active, S-isomer or S-enantiomer of the PPI omeprazole (the R-isomer), which