This Drug and Therapeutics Bulletin (DTB) reviews the evidence on eplerenone (Inspra®), an aldosterone-receptor antagonist used in the treatment of patients with left ventricular systolic dysfunction and heart failure following a myocardial infarct (MI).

The bulletin notes the following:

• When started 3 to 14 days after the infarct, eplerenone can decrease mortality and morbidity.

• Eplerenone can cause hyperkalaemia; serum potassium concentrations require monitoring

• There is no evidence on its efficacy after 16 months of treatment.

• No published trials have assessed the effects of spironolactone on clinical outcomes after a MI nor compared spironolactone and eplerenone, either after MI or in chronic heart failure.

• The cost to the NHS of 1 year’s treatment with eplerenone (50mg/d) is around £557. vs. £28 with spironolactone (25mg/d).

Because there is no clinical trial evidence to support the theory that spironolactone is as effective as eplerenone when used after MI, the bulletin states that substituting spironolactone for eplerenone cannot be recommended. It adds that there is no justification for using eplerenone outside the licensed indication (e.g. as a substitute for spironolactone in patients with chronic heart failure). This review is in line with NICE guidance on the secondary prevention of MI, which recommends that for patients who have had an acute MI and who have symptoms and/or signs of heart failure and LVSD, treatment with a licensed aldosterone antagonist for post-MI treatment should be initiated within 3–14 days of the infarct.