Mineralocorticoid Receptor Antagonists in Clinical Practice

Introduction to Mineralocorticoid Receptor Antagonists

Mineralocorticoid receptor antagonists (MRAs) are recommended by the American Heart Association for patients with Heart Failure with Reduced Ejection Fraction (HFrEF) and NYHA class II-IV symptoms, with a left ventricular ejection fraction (LVEF) ≤35%, as a Class I recommendation, significantly reducing mortality and morbidity when added to standard therapy 1, 2

MRAs have been demonstrated to be effective in landmark trials, including RALES (spironolactone), EPHESUS, and EMPHASIS-HF (eplerenone), for patients with HFrEF, providing a 30% relative risk reduction (RRR) in mortality in severe heart failure (RALES trial) and a 37% RRR in cardiovascular death or heart failure hospitalization in mild heart failure (EMPHASIS-HF trial) 2, 3
MRAs should be added to standard therapy including ACE inhibitor/ARB and beta-blocker for patients with HFrEF 4, 3

The American Diabetes Association recommends the use of MRAs for patients not meeting blood pressure targets on three classes of antihypertensive medications, including a diuretic, and for patients with resistant hypertension when added to existing treatment with ACE inhibitor/ARB, thiazide-like diuretic, and dihydropyridine calcium channel blocker 5
MRAs are indicated for patients with resistant hypertension who are not meeting blood pressure targets on three classes of antihypertensive medications, including a diuretic 6, 7

The American Diabetes Association indicates that MRAs are effective for patients with type 2 diabetes, eGFR ≥25 ml/min/1.73 m², normal serum potassium, and albuminuria, reducing albuminuria and providing cardiovascular benefits 8, 5
MRAs are indicated for patients with diabetic kidney disease, type 2 diabetes, eGFR ≥25 ml/min/1.73 m², normal serum potassium, and albuminuria (ACR ≥30 mg/g) 9

Adding an MRA to ACE inhibitor or ARB therapy significantly increases hyperkalemia risk, and for patients with serum creatinine >2.5 mg/dL for men or >2.0 mg/dL for women, caution is advised 1, 2, 5, 7, 10
For patients with elevated potassium levels (K+ >5.5 mmol/L), the dose of MRA should be halved and monitored closely, and for K+ >6.0 mmol/L, MRA therapy should be discontinued 2
The American College of Cardiology recommends spironolactone at an initial dose of 25 mg once daily as the first-line MRA treatment, with dose titration to 50 mg daily after one month if tolerated 4, 6, 11
Initial monitoring should include checking serum potassium and renal function within 1-2 weeks after initiation, and then at 4 weeks after initiation or dose change 4, 10
Long-term monitoring should be done every 6 months once stable, with more frequent testing for clinical instability 4
Discontinuation criteria include serum potassium that cannot be maintained at <5.5 mEq/L despite mitigation measures, and creatinine increases by more than 30% 4, 10
MRAs are contraindicated in patients with eGFR <30 mL/min/1.73 m² or serum potassium ≥5.0 mEq/L 4
Combination therapy with MRAs and both ACE inhibitors and ARBs should be avoided 12

MRAs provide high economic value in patients with HFrEF and NYHA class II-IV symptoms, making them a cost-effective therapeutic option when clinically indicated 4
Medication adherence should consider barriers such as cost and side effects when prescribing MRAs 5