Assessment of the novel selective aldosterone blocker eplerenone using ambulatory and clinical blood pressure in patients with systemic hypertension.

Eplerenone is a highly selective aldosterone blocking agent, which was recently approved for the treatment of hypertension and has also been shown to reduce mortality in post-myocardial infarction patients with heart failure. To assess its usefulness in patients with essential hypertension, we performed a 12-week, double-blind, placebo-controlled, parallel-arm, fixed-dose study over a range of doses using clinic and ambulatory blood pressure (BP). After single-blind placebo therapy for 3 to 4 weeks to obtain baseline measures, 400 patients were randomized to receive placebo or 1 of 4 doses of eplerenone (25, 50, 100, and 200 mg once daily). In addition, changes from baseline in serum potassium, active renin activity, and serum aldosterone were assessed. After 12 weeks of therapy, reductions in clinic BP showed a significant dose response in which 25 mg of eplerenone achieved statistical significance compared with placebo for systolic BP; maximum clinic BP reduction was achieved with the 100 mg dose. Ambulatory BP monitoring showed that all doses of eplerenone (25 to 200 mg/day) lowered BP significantly greater than placebo with a significant dose response. The 24-hour mean BP reductions ranged from 6.4/4.4 to 10.3/5.7 mm Hg on eplerenone compared with 1.3/0.8 mm Hg on placebo. One patient on placebo and 1 patient on 200 mg of eplerenone had episodes of elevated serum potassium levels (>5.5 mEq/L). Increases in serum aldosterone were related to dose but not to reductions in 24-hour BP. Side effects and withdrawal rates attributed to eplerenone were similar to those of placebo. These data show that eplerenone is an effective antihypertensive agent at doses as low as 25 mg/day. The top effective dose in stage 1 to 3 hypertension based on clinic and ambulatory BP was 100 mg once daily. The incidence of elevated serum potassium levels was not increased across doses of eplerenone in this study. [ABSTRACT FROM AUTHOR]