Eplerenone : a review of its use in left ventricular systolic dysfunction and heart failure after acute myocardial infarction

Eplerenone: a review of its use in patients with chronic systolic heart failure and mild symptoms

Eplerenone (Inspra®) is a selective mineralocorticoid receptor antagonist (MRA). In the EU, it is approved for use (in addition to standard optimal therapy) to reduce the risk of cardiovascular (CV) mortality and morbidity in adult patients with chronic systolic heart failure (HF) and mild symptoms. This article reviews the efficacy and tolerability of eplerenone in this indication and briefly summarizes its pharmacology. In the EMPHASIS-HF study, relative to placebo, the addition of eplerenone to optimal background therapy significantly reduced the risk of death from CV causes or hospitalization for HF in patients with chronic systolic HF and mild symptoms. Benefits of eplerenone therapy over placebo were also observed in several secondary outcomes, including: death from any cause or hospitalization for HF; death from any cause; hospitalization for any reason; or hospitalization for HF. Eplerenone was generally well tolerated in this study, with the most frequent adverse event being hyperkalaemia, which is a known adverse event of the drug class. Sexual adverse events (e.g. gynecomastia) occurred in <1 % of eplerenone recipients, reflecting the selectivity of eplerenone for mineralocorticoid receptors. Based on these results, European guidelines have been updated and recommend the use of an MRA to reduce the risk of HF hospitalization and premature death in all patients with persisting symptoms (New York Heart Association class II-IV) and a left-ventricular ejection fraction of ≤35 %, despite treatment with ACE inhibitor (or an angiotensin receptor blocker if an ACE inhibitor is not tolerated) and a β-blocker.

Contrasting effects of eplerenone and spironolactone on adrenal cell steroidogenesis

Spironolactone and eplerenone are widely used as mineralocorticoid antagonists. Spironolactone has several nonspecific actions including inhibition of androgen receptor and steroid hormone biosynthesis. While studies have shown that eplerenone does not exhibit nonspecific actions on androgen receptor, its effects on steroid hormone production have not been reported. Herein, the effects of eplerenone (0.1-30 microM) and spironolactone (0.1-30 microM) on steroid production were examined in human adrenocortical H295R cells. Spironolactone inhibited basal production of cortisol (91%) and aldosterone (53%). Treatment of H295R cells with angiotensin II (Ang II) for 24 h increased aldosterone production by 11-fold. Spironolactone inhibited Ang II stimulation of aldosterone production by 80%. Addition of pregnenolone increased aldosterone (9-fold) and cortisol (3-fold) production. Spironolactone inhibited pregnenolone metabolism to aldosterone (67%) and cortisol (74%). The inhibitory effects of spironolactone occurred at concentrations far higher than those needed to block mineralocorticoid receptor, suggesting an action directly on the enzymes involved in steroid production. In contrast, eplerenone did not inhibit basal, Ang II, forskolin, pregnenolone-stimulated cortisol, or aldosterone production. Together, these data demonstrate that opposed to spironolactone, pharmacologic concentrations of eplerenone do not inhibit adrenal cell aldosterone or cortisol production.

The effect of neurohormonal antagonists in reducing heart failure hospitalizations

OBJECTIVE

Heart failure (HF) is a major health problem facing the US and studies suggest that the incidence of this condition will rise significantly over the next 10 years. Limiting the incidence or duration of HF hospitalizations would, therefore, have a major impact on healthcare costs. The purpose of this review is to establish and discuss the proposed neurohormonal mechanisms by which HF can occur along with pharmacologic treatments designed to antagonize these pathological states in order to aid in the reduction of HF hospitalization.

METHODS

A Medline search (to December 200) was performed to compile published literature and assess numerous large-scale studies regarding the use of neurohormonal antagonists in the treatment of HF. In addition, evaluation of statistics and figures from various organizations dedicated to the improvement of HF care was utilized as aids in understanding the impact of these therapies on hospitalization and healthcare.

RESULTS

Heart failure is the most costly cardiovascular disease in the United States, with an estimated annual expenditure in excess of $20 billion. The frequency and duration of HF-associated hospitalizations are the key contributors to this pronounced economic burden. Use of pharmacologic interventions designed to specifically antagonize the renin-angiotensin-aldosterone system and the adrenergic system has had a significant impact on limiting hospitalization with regard to HF. However, the ever burdensome level of re-hospitalization rates for these patients is still problematic and appears to be based on a disconnect between established procedures to effectively treat these patients and the inability to accurately measure performance standards by managed care organization and hospital accreditation bodies. As a consequence, these antagonists, beta-blockers in particular, are still underutilized in the treatment of HF. Studies have shown that many of these hospitalizations could have been avoided had healthcare providers followed effective HF management programs.

CONCLUSIONS

Current evidence supports the benefits of neurohormonal blockade in decreasing hospital admissions due to HF. Appropriate use of these agents plus agreed-upon guidelines for treatment can continue to significantly decrease total HF-related hospitalizations and costs. Inclusion of beta-blockers as a performance measure in quality-of-care HF indicators should be considered as an important instrument to increase their utilization and to improve overall HF care.