Amiloride in the treatment of primary hyperaldosteronism and essential hypertension.

1. Amiloride (40 mg/day) was given to nineteen patients with primary hyperaldosteronism. There were significant falls in systolic and diastolic blood pressure, in total exchangeable sodium and in serum sodium and bicarbonate, while total exchangeable potassium, total body potassium, serum potassium, chloride and urea, plasma renin, angiotensin II and aldosterone all increased significantly. Amiloride was effective in reducing the blood pressure in patients with and without adrenocortical adenoma. No carry-over effect was seen on withdrawing amiloride. Similar changes were associated with amiloride treatment in five patients with essential hypertension; hyperkalaemia was not observed. 2. Only negligible side effects were encountered in the entire series of 24 patients.