Effect of chronic nifedipine in patients inadequately controlled by a converting enzyme inhibitor and a diuretic.

Nifedipine, in a slow release preparation, was given at a mean daily dosage of 47 +/- 4 mg to 12 patients with severe hypertension in whom arterial pressure was not satisfactorily controlled (mean arterial pressure 132 +/- 4 4 mm Hg) by the combination of a converting enzyme inhibitor and a diuretic. The addition of nifedipine induced an appreciable decrease in mean arterial pressure of 31 +/- 5 mm Hg and of serum potassium and plasma aldosterone. After adequate control of hypertension and because of severe hypokalemia in some patients, discontinuation of the diuretic was attempted in 10 subjects. After 1.7 +/- 0.5 months of treatment by the converting enzyme inhibitor and nifedipine no change in arterial pressure occurred while serum potassium had returned to normal in most patients. These results show that nifedipine may be useful in patients with a residual rise of arterial pressure when treated by converting enzyme inhibitor plus diuretics; in such patients, however, the serum potassium concentration should be carefully monitored. In addition, our observations suggest that calcium blockers may be an effective alternative to diuretics in patients receiving a converting enzyme inhibitor.