Omeprazole: a new approach to gastric acid suppression.

Omeprazole, one of a new group of antisecretory drugs, is a substituted benzimidazole that does not exhibit the anticholinergic or histamine H2 antagonistic properties of drugs such as cimetidine. This agent suppresses gastric acid secretion by inhibiting the proton pump mechanism, thereby blocking the final step of acid secretion. Omeprazole is significantly more effective than the histamine H2 receptor antagonists in eliminating acid secretion; thus, it may be beneficial in patients who are resistant to these agents. Omeprazole is indicated for severe erosive esophagitis, gastroesophageal reflux disease that does not respond to H2 receptor antagonists, and hypersecretory diseases such as Zollinger-Ellison syndrome and systemic mastocytosis. Because of the theoretic risk of carcinogenesis, short-term therapy is recommended, although long-term therapy is required for hypersecretory diseases.