[The second generation of gastric antisecretory agents: omeprazole]

Omeprazole is the first representative of a new class of gastric acid secretion inhibitors. It acts by specific and prolonged inhibition of H+K+ ATPase, or proton pump, which is the terminal and compulsory stage of acid secretion by the parietal cells. The drug therefore inhibits both basal and stimulated secretion. It appears from therapeutic trials that omeprazole administered in doses of 20 mg a.m. once a day is superior to the H2-receptor antagonists in the healing of active duodenal ulcers and ulcerated reflux oesophagitis. It is as active or slightly more active than histamine inhibitors in gastric ulcers. Finally, it is the treatment of choice to prevent ulcerations in Zollinger-Ellison syndrome. These are the 4 indications for omeprazole at the moment. The use of that drug for periods of a few weeks has not given rise to any significant side-effect.