부산대학교 도서관

A variety of gastrointestinal diseases involve an imbalance between the protective actions of the gastrointestinal mucosa and the destructive actions of hydrochloric acid, which is secreted by the stomach. Many forms of treatment involve pharmacological agents that suppress gastric acid. Gastric acid is secreted from the parietal cells of the stomach through a process critically dependent on the enzyme hydrogen/potassium-ATPase, which exchanges intracellular hydrogen ions for extracellular potassium ions, thus increasing the acidity of the extracellular environment. As a novel drug for the suppression of gastric acid secretion, omeprazole is a specific inhibitor of this enzyme. Omeprazole is not stable in an acidic environment like the stomach, so it is administered as enteric-coated capsules, which do not dissolve until they reach the duodenum. The onset of action of omeprazole is approximately one hour, with a peak activity six hours after administration. As a result of omeprazole's suppression of gastric acid secretion, it also has the effect of causing a counter-regulatory increase in the release of gastrin (a hormone that induces acid secretion) from the cells of the stomach, and in the long-term, the number of gastrin-secreting cells is increased. This does not appear to enhance the likelihood of either ulcer recurrence following drug termination or neoplastic alterations in the cells of the stomach. Omeprazole has recently been approved by the FDA for use in the treatment of duodenal ulcer and gastric ulcer. It is also used in the treatment of both refractory ulcerative conditions that do not respond to more conventional forms of therapy and gastroesophageal reflux esophagitis (inflammation of the esophagus caused by regurgitated gastric acid). An extremely low incidence of side effects and a favorable safety profile make this drug very promising for treatment of a wide variety of gastric acid-related disorders. (Consumer Summary produced by Reliance Medical Information, Inc.)