About omeprazoleproton pump inhibitor, substituted benzimidazole, anti-secretory,antiulcer.mechanism of action of omeprazoleomeprazole is a proton pump inhibitor and 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 omeprazole 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. omeprazole irreversibly inhibits proton pumps activity and decreases gastric acid secretion.indications for omeprazole1. duodenal ulcer 2. gastric ulcer 3. zollinger- ellison syndrome 4. gastroesophageal reflux disease 5. oesophagitis 6. acid related dyspepsia 7. nsaid associated ulceration 8. prophylaxis of acid aspiration during anesthesia interactions for omeprazolediazepam: half life of diazepam is increased. phenytoin: increased