Eplerenone Versus Spironolactone in Resistant Hypertension: an Efficacy and/or Cost or Just a Men's Issue?

PURPOSE OF REVIEW: To review comparative efficacy and tolerability data between the two main mineralocorticoid receptor antagonists (MRAs), spironolactone and eplerenone, in patients with resistant hypertension (HTN). The focus was whether spironolactone, being the classical non-selective agent that has been used for years, albeit with several anti-androgenic side effects, can be rivaled by eplerenone, an apparently weaker, but better tolerated, more selective MRA. RECENT FINDINGS: Evidence has accumulated that resistant HTN is generally volume-dependent, attributable to varying degrees of aldosterone excess with its attendant renal effects of sodium and fluid retention. Such aldosteronism may be due to an underestimated occurrence of primary aldosteronism; however, it more commonly occurs separately from it and independent from angiotensin II. The aldosterone-induced volume excess placed at the root of the development of resistant HTN in a large number of patients, together with the extrarenal deleterious effects of aldosterone, such as endothelial dysfunction, vascular remodeling and increased arterial stiffness, cardiac hypertrophy, and fibrosis can all be counterbalanced by the administration of MRAs. In the absence of a direct comparison between spironolactone and eplerenone, and in light of compelling evidence provided by the recently reported results of the PATHWAY-2 and ReHOT studies, spironolactone has been established as the most effective add-on anti-aldosterone therapy in resistant HTN. The data on use of eplerenone continue to emerge and are quite encouraging. Despite the lack of direct comparative data, the weight of evidence regarding efficacy is currently in favor of spironolactone. However, the data on the efficacy of eplerenone are promising but still being accumulated suggesting this agent as an alternative to spironolactone and certainly as the preferred choice for those not tolerating spironolactone, especially for patients developing anti-androgenic side effects like breast tenderness, gynecomastia/mastodynia, and/or sexual dysfunction. Both these agents appear to have several other pleiotropic effects that confer cardioprotection and renoprotection beyond their antihypertensive effect. Potassium levels and renal function need to be closely monitored during administration of these therapies. Future comparative studies may shed more light on these issues, while emerging newer agents may offer better and safer therapeutic options.

Neprilysin Inhibitors: Filling a Gap in Heart Failure Management, Albeit Amidst Controversy and at a Significant Cost.

Dual angiotensin and neprilysin inhibition using the combination drug sacubitril-valsartan has ushered in a new era in the treatment of heart failure (HF). The randomized controlled PARADIGM-HF trial, which randomized 8399 patients with HF to enalapril or sacubitril-valsartan, showed a 20% reduction in mortality and HF hospitalization with the new drug. This has been heralded as a step toward filling a crucial gap in HF management by providing strong evidence that combined inhibition of the angiotensin receptor and neprilysin is superior to inhibition of the renin-angiotensin system alone in stable patients with chronic HF as it negates the deleterious effects of angiotensin while concomitantly augmenting the beneficial effects of the endogenous natriuretic peptide system. This new therapy is costly, and other confirmatory studies have been lacking for over 2 years since its approval by major regulatory authorities. As such, controversy and heated discussions have amassed, as has detailed information from a plethora of secondary analyses of this pivotal trial about the pros and cons of this promising new therapeutic strategy in HF management. The aim of this review was to provide a critical assessment of all these aspects.