Eplerenone in the treatment of chronic heart failure

There has been a recent revival of interest in aldosterone receptor antagonists for the treatment of chronic heart failure. This was largely triggered by fresh insights into the role of aldosterone in a number of key pathophysiological processes, including fibrosis and remodeling, inflammation, and the potentiation of catecholamine effects. The therapeutic efficacy of spironolactone (Aldactone^®, Pfizer) in severe chronic heart failure was established by the Randomized Aldactone Evaluation Study, but hormonal side effects (gynecomastia) associated with the drug posed a problem. More recently, the Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study has provided firm support for the use of eplerenone (Inspra?, Pfizer) in heart failure following acute myocardial infarction in addition to neurohormonal blockade with angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers and β-blockers. This strategy can be expected to benefit both mortality and morbidity. Due to the fact that eplerenone is a selective aldosterone receptor antagonist, it does not cause troublesome hormonal side effects. This is an important feature of the drug that is likely to help maintain compliance.     

New treatment option for heart failure patients: eplerenone

Aldosterone plays an important role in the harmful cardiac remodeling process and pathophysiology of heart failure after a myocardial infarction. Until recently, spironolactone (Aldactone) was the only pharmacologic agent available to directly block the deleterious effects of aldosterone. The use of spironolactone is complicated by its antiprogesterone and antiandrogen side effects, such as gynecomastia and menstrual irregularities. Eplerenone (Inspra), a member of a new class of drugs called selective aldosterone receptor antagonists, was recently approved for the treatment of both hypertension and post-myocardial infarction heart failure and appears to be devoid of the antiprogesterone and antiandrogen effects. In a trial in patients with heart failure following a myocardial infarction, eplerenone treatment significantly reduced mortality and morbidity compared to placebo. Eplerenone may be considered as part of the therapeutic plan in patients who have suffered a myocardial infarction and demonstrate evidence of heart failure.     

The role of aldosterone receptor antagonists in the management of heart failure: An update

The aldosterone receptor antagonists (ARAs) spironolactone (Aldactone) and eplerenone (Inspra) have become part of standard medical therapy for heart failure, having shown clinical efficacy in randomized trials in patients with advanced symptomatic systolic heart failure, postinfarction heart failure with cardiac dysfunction, and systolic heart failure with mild symptoms. The benefits include a lower rate of death. Yet to be answered is whether the two drugs are clinically equivalent; another question is whether they may benefit everyone with symptomatic heart failure, including diastolic heart failure.     

Aldosterone receptor antagonists for heart failure: current status, future indications

Many patients with heart failure should receive an aldosterone receptor antagonist, ie, either spironolactone (Aldactone) or the newer agent eplerenone (Inspra)--in addition to an angiotensin-converting enzyme (ACE) inhibitor or an angiotensin II receptor blocker (ARB) or both, and a beta-blocker. We review the evidence and indications.     

The role of aldosterone in heart failure and the clinical benefits of aldosterone blockade

Aldosterone has a variety of detrimental effects on the heart and vasculature and is increasingly recognized as an important target in chronic heart failure, as illustrated by the Randomized Aldactone Evaluation Study. In this article, the evidence supporting the cardiovascular effects of aldosterone in humans and the proven benefits of aldosterone-receptor antagonists in heart failure shall be discussed.     

The role of aldosterone in heart failure and the clinical benefits of aldosterone blockade

Aldosterone has a variety of detrimental effects on the heart and vasculature and is increasingly recognized as an important target in chronic heart failure, as illustrated by the Randomized Aldactone Evaluation Study. In this article, the evidence supporting the cardiovascular effects of aldosterone in humans and the proven benefits of aldosterone-receptor antagonists in heart failure shall be discussed.     

Aldosteron und Aldosteronrezeptorantagonisten in der Herzinsuffizienztherapie

In addition to the classical effects exerted by aldosterone on water and electrolyte haemostasis, recent data suggest additional roles in the pathophysiology of cardiovascular diseases. Examples are the regulation of blood pressure (by direct aldosterone effects on vessels and the CNS), myocardial hypertrophy and remodelling. Two aldosterone receptor antagonists, spironolactone and eplerenone, are currently available for the long-term therapy of chronic heart failure. Both compounds have clearly demonstrated their efficacy in heart failure treatment in end-point based clinical trials. Spironolactone, in addition to its antagonistic effects on the mineralocorticoid receptor, has anti-androgenic and gestagenic actions which can lead to endocrine side effects. Eplerenone selectively blocks aldosterone receptors and thus lacks adverse effects caused by non-specific steroid receptor blockade. The elimination half-life of eplerenone is shorter than the half-life of the active metabolites of spironolactone. Eplerenone is metabolised by CYP3A4, and pharmacokinetic interactions with inhibitors and inducers of this enzyme have to be considered. Essential for the clinical use of aldosterone antagonists in heart failure is the careful monitoring of potassium levels and renal function. The recommended doses should be followed precisely. Higher doses increase the risk of developing life-threatening hyperkalemia. Particular attention has to be paid to patients with impaired renal function. Aldosterone receptor antagonists should not be used when the glomerular filtration rate is below 50 ml/min.     

Eplerenone--a novel selective aldosterone blocker

OBJECTIVE: To review the pharmacology, pharmacokinetics, clinical efficacy, and safety of eplerenone, a new selective aldosterone blocker. DATA SOURCES: Primary literature and review articles were obtained via MEDLINE search (1966-April 2002). Additional studies and abstracts were identified from the bibliographies of reviewed literature. STUDY SELECTION AND DATA EXTRACTION: Studies and review articles related to eplerenone, aldosterone, aldosterone antagonist, and spironolactone were reviewed. Data pertinent to this article were included. DATA SYNTHESIS: Eplerenone is a selective aldosterone blocker. Recent data have demonstrated the deleterious effects of aldosterone in several chronic disease states including hypertension and heart failure. Animal studies using eplerenone have shown a positive role for aldosterone antagonism in the treatment of hypertension, heart failure, myocardial infarction, renal disease, and atherosclerosis. In humans, eplerenone appears to be effective for the treatment of hypertension. An ongoing study will examine the effect of eplerenone for heart failure. To date, the incidence of adverse effects with eplerenone has been slightly lower than with spironolactone. CONCLUSIONS: Eplerenone appears to be a promising drug in a new class of agents called selective aldosterone blockers. The drug may be approved for treatment of hypertension in 2002. Additional studies are ongoing that may provide information on other clinical uses for this medication.     

Eplerenone: a selective aldosterone receptor antagonist for patients with heart failure

OBJECTIVE: To evaluate the pharmacology, pharmacokinetics, safety, and clinical use of eplerenone in heart failure (HF). DATA SOURCES: English-language MEDLINE searches were performed from 1966 to May 2004. Key words included eplerenone, aldosterone receptor antagonist, heart failure, myocardial infarction, left-ventricular dysfunction, and cost-effectiveness. Additional references were identified from bibliographies of selected articles. STUDY SELECTION AND DATA EXTRACTION: Human trials evaluating the efficacy, safety, and cost-effectiveness of aldosterone receptor antagonists in HF were evaluated. DATA SYNTHESIS: Eplerenone is the first selective aldosterone receptor antagonist. The drug is indicated to improve the survival of stable patients with left-ventricular systolic dysfunction (ejection fraction <40%) and clinical evidence of HF following acute myocardial infarction. Efficacy and safety in this population have been demonstrated in a large, randomized clinical trial. Eplerenone is associated with severe and sometimes life-threatening hyperkalemia. Patients with reduced renal function and diabetes, as well as those on other drugs that increase potassium levels, are at highest risk. Eplerenone is metabolized by the cytochrome P450 system and may interact with drugs that interfere with this system. A major advantage of eplerenone over the nonselective aldosterone receptor antagonist spironolactone is lack of binding to progesterone and androgen receptors, which is associated with drug-induced gynecomastia, breast pain, and impotence. CONCLUSIONS: The addition of eplerenone to traditional HF therapy has been shown to reduce morbidity and mortality in patients who develop left-ventricular dysfunction after acute myocardial infarction. Eplerenone's selectivity reduces sex hormone-related adverse effects. Despite these benefits, the overall cost-effectiveness has yet to be determined.     

The cardiovascular effects of eplerenone, a selective aldosterone-receptor antagonist

BACKGROUND: The role of the renin-angiotensin-aldosterone system in the pathophysiology and treatment of hypertension and heart failure has been extensively studied. Angiotensin-converting enzyme inhibitors and angiotensin II-receptor blockers have been shown to effectively reduce blood pressure, protect the kidney, and reduce morbidity and mortality in patients with heart failure. Therefore, there is increased interest in the effects of aldosterone and the use of aldosterone-receptor antagonists in the treatment of cardiovascular disease. Eplerenone is the first selective aldosterone-receptor antagonist approved for the treatment of hypertension and left ventricular (LV) dysfunction after acute myocardial infarction (AMI). OBJECTIVE: The goal of this article was to review the pharmacologic properties, clinical efficacy, and tolerability of eplerenone in the treatment of hypertension, LV dysfunction, and proteinuria. METHODS: Relevant English-language articles were identified through searches of MEDLINE (1966-May 2003), Current Contents, and International Pharmaceutical Abstracts (1970-May 2003) using the terms hypertension, heart failure, eplerenone, aldosterone, and aldosterone antagonist. Other pertinent publications were identified from the reference lists of the identified articles. Information was also obtained from abstracts presented at national meetings and data on file with the manufacturer. RESULTS: In clinical trials, eplerenone alone and in combination with renin-angiotensin blockade significantly reduced both systolic and diastolic blood pressure compared with placebo (P < 0.05 to P < 0.001). In EPHESUS (Eplerenone Post-Acute Myocardial Infarction Heart Failure Efficacy and Survival Study), the addition eplerenone to optimal medical therapy reduced morbidity and mortality in patients with AMI and LV dysfunction, although the incidence of serious hyperkalemia was also significantly greater. In comparisons with spironolactone, eplerenone was associated with a lower incidence of gynecomastia and other sex hormone-related adverse effects. CONCLUSIONS: Either alone or in combination with other antihypertensive agents, eplerenone appears to be effective for the treatment of hypertension. Morbidity and mortality were reduced when eplerenone was added to standard therapy for LV dysfunction complicating AMI. The use of eplerenone for hypertension or heart failure may be limited in patients at risk for hyperkalemia.     

醛固酮拮抗剂螺内酯治疗慢性心力衰竭临床观察

目的分别判断血浆醛固酮水平〉正常者及醛固酮水平≤正常者两组患者对醛固酮拮抗剂螺内酯治疗的疗效。方法将慢性充血性心力衰竭患者342例,随机分为螺内酯治疗组（常规治疗＋螺内酯）及对照组（仅行常规治疗）,在出院时观察两组患者心功能改善情况,作对照比较。结果342例CHF患者中228例（66．6％）血醛固酮水平〉正常,螺内酯治疗疗效明显（P〈0．01）;114例（33．3％）血醛固酮水平≤正常,螺内酯治疗与仅行常规治疗相比差异无统计学意义（P〉0．05）。结论螺内酯对血醛固酮水平〉正常的CHF患者具有良好疗效。     

Neurohormones and heart failure: the importance of aldosterone

Heart failure is a major cause of cardiovascular morbidity and mortality and its incidence is on the increase. The pathophysiology of heart failure is multi-factorial but recent studies suggest that aldosterone plays an important and independent role in its progression. Emerging evidence now suggests that aldosterone exerts renal-independent effects. It binds to its mineralocorticoid receptor to produce direct effects on the myocardium and vasculature, leading to damaging processes such as hypertrophy, necrosis, fibrosis and endothelial dysfunction, factors known to contribute to the pathophysiology of heart failure. Mineralocorticoid receptor antagonists have thus emerged as a new paradigm for the treatment of heart failure. The benefits of these agents on both morbidity and mortality when used in patients with chronic symptomatic heart failure have been demonstrated by recent trials.     

Differential restoration of functional hyperemia by antihypertensive drug classes in hypertension-related cerebral small vessel disease

Dementia resulting from small vessel diseases (SVDs) of the brain is an emerging epidemic for which there is no treatment. Hypertension is the major risk factor for SVDs, but how hypertension damages the brain microcirculation is unclear. Here, we show that chronic hypertension in a mouse model progressively disrupts on-demand delivery of blood to metabolically active areas of the brain (functional hyperemia) through diminished activity of the capillary endothelial cell inward-rectifier potassium channel, Kir2.1. Despite similar efficacy in reducing blood pressure, amlodipine, a voltage-dependent calcium-channel blocker, prevented hypertension-related damage to functional hyperemia whereas losartan, an angiotensin II type 1 receptor blocker, did not. We attribute this drug class effect to losartan-induced aldosterone breakthrough, a phenomenon triggered by pharmacological interruption of the renin-angiotensin pathway leading to elevated plasma aldosterone levels. This hypothesis is supported by the finding that combining losartan with the aldosterone receptor antagonist eplerenone prevented the hypertension-related decline in functional hyperemia. Collectively, these data suggest Kir2.1 as a possible therapeutic target in vascular dementia and indicate that concurrent mineralocorticoid aldosterone receptor blockade may aid in protecting against late-life cognitive decline in hypertensive patients treated with angiotensin II type 1 receptor blockers.     

Spironolactone use in patients with heart failure

BACKGROUND: The addition of spironolactone, an aldosterone antagonist, to standard therapy can reduce the risk of both morbidity and mortality in patients with severe heart failure. OBJECTIVE: To evaluate the use of spironolactone in class III and IV heart failure patients in four urban teaching hospitals. METHODS: We conducted a concurrent medical record review of 163 patients with documented heart failure admitted to a general medicine service over a 5-week period. Data retrieved included patient demographics, heart failure class, left ventricular ejection fraction, spironolactone contraindications, spironolactone use, dose and frequency, and other heart failure medication use, dose and frequency. All data reflected patients' baseline status. RESULTS: Our patient population was 80% white people, 61% male, with a mean age of 70 years (35-99). A total of 114 had class III or IV heart failure (70%). Angiotensin-converting enzyme inhibitors or appropriate alternative were prescribed in 117 (72%) patients, whereas beta-blockers were used in 121 (74%) patients. Fifty-seven patients met spironolactone ideal candidate criteria. Of these, eight (14%) were appropriately prescribed spironolactone. CONCLUSIONS: Three years after publication of the Randomized Aldactone Evaluation Study, spironolactone is underutilized in the treatment of heart failure. Results of this study indicated that the majority of patients in class III or IV heart failure were not prescribed spironolactone. Improvements in spironolactone prescribing are needed.     

Aldosterone antagonists in heart failure

Aldosterone antagonists represented by nonselective spironolactone and mineralocorticoid-selective eplerenone are approved for treatment of symptomatic heart failure with reduced systolic function. Their cardioprotective, antifibrotic, and antiarrhythmic effects have been proven in animal experiments, and their effects on morbidity and mortality have been demonstrated in randomized clinical trials. Yet, they remain the most underutilized of all classes of medications for heart failure, primarily because of fear of hyperkalemia. Thorough patient screening and selection is the key for minimizing risks and optimizing benefits from these drugs. Ongoing trials will demonstrate whether the indication for aldosterone antagonists can be expanded to less severe heart failure or patients with preserved systolic function.     

Therapy for heart failure

The treatment of congestive heart failure focuses on three steps: 1. Elimination of the precipitating cause or mechanism, and/or treatment of the underlying disease respectively. 2. Treatment of the failing heart syndrome itself. We shall concern ourselves with pharmacotherapy, omitting technical and surgical aspects. 3. Prophylactic treatment of complications, such as thromboembolism and arrhythmias. Drugs for the treatment of heart failure can be classified as follows: 1. Diuretics 2. Vasodilators 3. Neurohumoral Inhibitors 4. Inotropic drugs. Diuretics improve symptoms and exercise capacity and probably survival. They are the drug of first choice in acute and chronic heart failure. Potassium supplementation is necessary. Renal function needs to be monitored. The aldosterone antagonist spironolactone has probably important effects upon the myocardium. It retards fibrous tissue development and improves prognosis. Vasodilators unload the heart and improve contractile geometry and hemodynamics, thereby lessening symptoms. Prognosis, however, is not affected. They are indispensable in acute heart failure. In longterm treatment only the combination of nitrates with hydralazin has been shown to be effective. Angiotensin converting enzyme inhibitors combine vasodilation with neurohumoral inhibition. They are most effective in improving symptoms, exercise capacity and surviving chronic heart failure. If side effects (cough, allergy) prevent their use, then angiotensin II receptor antagonists can be used with equal benefit. However, both groups of drugs impair renal function and cannot be given in advanced renal failure or renal artery stenosis. Beta-receptor antagonists, previously considered contraindicated in heart failure are today amongst the most important drugs in heart failure. They improve survival and retard the need for cardiac transplantation in advanced failure. Their use, however, is rather difficult requiring extremely slow dose titration beginning with very low doses. Inotropic drugs are today mainly used in acute failure and cardiogenic shock. In longterm treatment only the digitalisglycosides have been shown to be effective in improving symptoms, exercise capacity and the general clinical course. Often antiarrhythmic treatment is necessary. Here amiodarone is the drug of choice today if beta blockers do not suffice. Prophylactic anticoagulation is indicated in all cases NYHA III and IV, with large hearts already in II. Future developments may include new inotropes, the ANP-system, and cytokines, as well as gene therapy for correction of myocardial phenotype change.     

Update of diuretics in the treatment of hypertension

Diuretics, which are primarily used to modify the volume and the composition of body fluids, are widely used to treat hypertension. The diuretics include a) the thiazides and thiazide-like agents, which are the most common drugs used to treat high blood pressure (these drugs inhibit sodium reabsorption in the early distal convoluted tubule); b) loop diuretics, such as furosemide, block chloride and sodium reabsorption by inhibition of the Na/K/2Cl cotransport system in the thick ascending limb of the loop of Henle; and c) potassium-sparing (retaining) diuretics, including aldosterone receptor blockers (such as spironolactone and eplerenone) and epithelial sodium channel blockers (such as amiloride and triamterene, which interfere with the reabsorption of sodium and excretion of potassium and hydrogen that takes place in the late distal tubule, the connecting tubule, and the cortical collecting duct). Hydrochlorothiazide 12.5 mg once daily or equivalent low dosages of other similar agents reduce blood pressure in approximately one-half to two-thirds of patients who are responsive to this class of drugs; higher doses add little to the effect on blood pressure and also increase side effects. Some combinations of very small doses of thiazide diuretics - for example, 6.25 mg hydrochlorothiazide or 0.625 mg indapamide, with a low dose of an antihypertensive drug of a different class - have average antihypertensive efficacy when used once daily. Furosemide is used in patients with renal failure or severe heart failure and is best given by continuous intravenous infusion. The potassium-sparing diuretics are generally used in combination with thiazide diuretics to treat hypertension. Side effects occur at about the same frequency and severity with equipotent doses of all diuretics. The incidence of side effects is dose-dependent and also increases as a function of the duration of the renal excretory and antihypertensive actions. However, longer-acting diuretics provide better 24-hour control of blood pressure and increase compliance and adherence to the treatment regimen.     

Renin-angiotensin system and heart failure

The local renin-angiotensin system in cardiac tissue has been demonstrated to be involved in the pathophysiology of cardiac hypertrophy and heart failure. Angiotensin II type 1(AT1) receptor stimulation leads to vasoconstriction, cell growth, oxidation, aldosterone release, and fibrosis. Recent evidence suggests that angiotensin II type 2(AT2) receptor exerts cardioprotective effects by counteracting against AT1 receptor. However, the role of AT2 receptor signaling in cardiac hypertrophy and fibrosis still remain controversial. This review focused on the accumulating evidence for the cardiac renin-angiotensin system in heart failure.     

Eplerenone for the treatment of cardiovascular disorders

The clinical utility and ultimately guideline recommendations for aldosterone receptor-blocking agents in cardiovascular disorders is clearly mentioned by a number of major clinical outcome trials. This article reviews the pharmacology, clinical efficacy and safety of the two currently available receptor blocking agents: spironolactone and eplerenone. The potential utility of eplerenone and other mineralocorticoid receptor agents beyond current clinical indications will also be examined.