Omeprazole in Zollinger-Ellison syndrome. Effects of a single dose and of long-term treatment in patients resistant to histamine H2-receptor antagonists.

We studied the effect of omeprazole, a benzimidazole inhibitor of gastric acid secretion, in patients with Zollinger-Ellison syndrome. In five patients ingestion of 80 mg of omeprazole inhibited gastric acid secretion by 26 to 100 per cent after 6 hours and by 76 to 100 per cent after 24 hours. Seven patients were continuously treated with omeprazole once or twice daily for 8 to 19 months (average, 14). Six of these seven had symptoms that were resistant to high doses of histamine H2-receptor antagonists, and the seventh could not take high doses of cimetidine because of a possible drug-related increase in the serum creatinine concentration. Symptoms resolved in all patients within two weeks, and peptic lesions were healed at endoscopy after four weeks. All patients remained free of symptoms, and gastric acid secretion continued to be markedly inhibited by omeprazole therapy. We conclude that omeprazole is a potent and long-acting antisecretory drug in patients with Zollinger-Ellison syndrome and that it is effective in patients whose peptic-ulcer disease is relatively resistant to treatment with histamine H2-receptor antagonists. Its safety and effectiveness in long-term therapy remain to be assessed.