Present experiences with omeprazole in the Zollinger-Ellison syndrome.

As effective tumour resection can be achieved in only a minority of patients with Zollinger-Ellison syndrome, therapy in such patients is usually directed to treatment and prevention of symptoms induced by hypersecretion of gastric acid. Omeprazole is a potent and long-acting inhibitor of pentagastrin stimulated gastric acid secretion in normal subjects, and this prompted a study of the effect of omeprazole on gastric acid hypersecretion and acid peptic disease resulting from endogenous hypergastrinaemia in Zollinger-Ellison patients. Omeprazole was found to be effective even in those patients whose symptoms were not adequately controlled by high doses of histamine H2-receptor antagonists, with or without pirenzepine. Serum gastrin levels were not affected; no laboratory abnormalities and minimal side-effects induced by omeprazole have been reported in Zollinger-Ellison patients even on long-term studies of up to 27 months.