About Esomeprazole A proton pump inhibitor, Substituted Benzimidazole, Antiulcer, antisecretory drug. Mechanism of Action of Esomeprazole Esomeprazole is the S enantiomer of Omeprazole and is a proton pump inhibitor. It is a prodrug. After administration it diffuses in to the parietal cell of the stomach and accumulates in the secretory canaliculi. In the acidic medium Esomeprazole is converted to sulfenamide. This sulfenamide covalently interacts with sulfhydryl (SH) group in the proton pump (H+ K+ATPase) and inhibits the exchange of extracellular K+ for intracellular H+ ion. Esomeprazole irreversibly inhibits proton pumps activity and decreases gastric acid secretion. As compared to Omeprazole, Esomeprazole produces better control of intragastric acidity in Gastroesophageal reflux diseases. It is as effective as Omeprazole in other disease condition. Indications for Esomeprazole 1.Gastric ulcer 2.Gastroesophageal reflux disease 3.Oesophagitis 4.NSAID associated ulcerat