Use of omeprazole in Zollinger-Ellison syndrome: a prospective nine-year study of efficacy and safety

Authors

  • D. C. METZ,

    1. Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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  • D. B. STRADER,

    1. Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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  • M. ORBUCH,

    1. Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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  • P. D. KOVIACK,

    1. Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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  • K. M. FEIGENBAUM,

    1. Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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  • R. T. JENSEN

    Corresponding author
    1. Digestive Diseases Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Bethesda, Maryland, USA.
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Dr. R. T. Jensen, Building 10. Room 9C-103. National Institutes of Health. Bethesda, MD 20892, USA.

SUMMARY

H+, K+-ATPase inhibitors such as omeprazole are the antisecretory agents of choice for the management of gastric acid hypersecretory states, including the Zollinger-Ellison syndrome. However, long-term follow-up data on the overall efficacy and safety of these agents in large numbers of patients are lacking. In the current study we examined the long-term efficacy and safety of omeprazole in 116 patients with Zollinger-Ellison syndrome treated with oral omeprazole at a single centre for up to 114 months (mean ± S.E.M. = 38 ± 3 months). The initial omeprazole maintenance dose was established according to the acute upward dose titration method in 89/116 patients (77%). Gastric acid output was effectively controlled using 60 mg of omeprazole once daily in 41/89 patients (46%) and 22/89 patients (25 %) required twice daily omeprazole therapy. The mean ranitidine equivalent dose for patients who required 60 mg omeprazole once daily (2.5 ± 0.2 g/day) was significantly lower than the mean ranitidine equivalent dose for patients who required more than 60 mg omeprazole once daily (4.3 ± 0.3 g/day). Long-term omeprazole maintenance therapy was discontinued in 36/116 patients (31%) but in no cases was discontinuation due either to drug-induced side-effects or uncontrolled gastric acid output. Fasting serum gastrin levels were significantly elevated above pre-treatment levels at only one time point during follow-up and were likely due to tumour growth rather than a drug effect. The final long-term omeprazole maintenance doses were lower than the initial doses but correlated closely with the preomeprazole basal acid output (r= 0.41, P < 0.001) and ranitidine equivalent dose requirements (r= 0.49, P < 0.001). We conclude that omeprazole effectively and safely controls gastric acid hypersecretion in all patients with Zollinger-Ellison syndrome for up to nine years without evidence by tachyphylaxis.

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