Eplerenone (Inspra), a new aldosterone antagonist for the treatment of systemic hypertension and heart failure.

Eplerenone is the second oral aldosterone antagonist available in the USA for the treatment of essential hypertension and heart failure. Treatment has been associated with reductions in blood pressure and improved survival (15% reduction in total mortality) for patients with heart failure who are in stable condition after a myocardial infarction. Due to the selectivity of eplerenone for the aldosterone receptor, adverse effects such as gynecomastia and vaginal bleeding seem to be less likely in patients who take eplerenone than in those who take spironolactone. The most severe side effect of spironolactone, hyperkalemia, was also observed with eplerenone. While eplerenone is more selective, with the potential for fewer side effects, its overall efficacy has not been proven to be superior to that of spironolactone in clinical trials. The American College of Cardiology recommends trying spironolactone first and then switching to eplerenone if patients develop gynecomastia, menstrual irregularities, or impotence.