Effect of omeprazole and cimetidine on plasma aldosterone response to angiotensin II

Objective: The Effect of omeprazole, a proton pump inhibitor, and cimetidine, an H2-receptor antagonist, on plasma aldosterone (PA) response to angiotensin II (AII) were evaluated. Methods: Furosemide (a loop diuretic agent, 20 mg) was given intravenously to eight healthy subjects during a control period, and after pretreatment with omeprazole (20 mg daily) or cimetidine (800 mg daily) for 6 days. Blood samples for determination of plasma renin activity (PRA), AII, PA, adrenotorticotropic hormone (ACTH) and potassium were obtained just before, and 30, 60 min and 120 min after furosemide administration. Results: PRA, AII and PA increased significantly after furosemide administration whereas ACTH and potassium did not. Significant correlations between plasma AII and PA were obtained in the control and omeprazole trial, but not in the cimetidine trial. The slope of the regression lines of the control and omeprazole trials did not differ significantly. Conclusion: These results suggest that, in contrast to cimetidine, the inhibitory effect of omeprazole on AII-stimulated aldosterone production following dosing with furosemide is negligible.