Effects of captopril and enalapril on zinc metabolism in hypertensive patients

Objective: To investigate the effects of chronic captopril and enalapril treatment on zinc metabolism in hypertensive patients by assessing zinc levels in serum, urine and monocytes. Methods: Patients with newly diagnosed essential hypertension were randomly divided into two treatment groups: those treated with captopril only (n=16) and those treated with enalapril only (n=18). Ten healthy subjects served as controls. Prior to the start of treatment and again 6 months later, zinc was assessed in the serum, in urine collected over 24 hours, and in peripheral blood monocytes. Results: Significant enhancement of 24-hour urinary zinc excretion (μg/24 hour) after 6 months of treatment was observed only in the captopril-treated group (p<0.01). However, intramonocytic zinc levels decreased significantly in both of the treated groups over the same period (p<0.01 and p<0.04 in the captopril- and enalapril-treated groups, respectively). Conclusion: Treatment of hypertensive patients with captopril or enalapril may result in zinc deficiency.