Captopril before and after spironolactone therapy in primary aldosteronism. Pathogenetic and therapeutical aspects

In three patients with primary aldosteronism, the acute effect of a single dose of captopril on the elevated mean arterial blood pressure (MAP) was studied before and after 4 weeks of treatment with spironolactone. Before spironolactone therapy, captopril did not cause any drop in MAP. Four weeks later, after an oral daily dose of 400 mg spironolactone, MAP was still elevated in all three patients, though electrolyte abnormalities were fully corrected. Since plasma renin activity (PRA) was increased to values above the normal range, the acute effect of captopril on MAP was tested again. A single dose of 25 mg captopril then caused a fall in MAP to normal. These data reveal the conversion from a renin-independent to a renin-dependent kind of hypertension after spironolactone therapy in three patients with primary aldosteronism syndrome. This might be of pathogenetic and therapeutic interest.