Clinical benefit of eplerenone in patients with mild symptoms of systolic heart failure already receiving optimal best practice background drug therapy: analysis of the EMPHASIS-HF study.

BACKGROUND: In EMPHASIS-HF (Eplerenone in Mild Patients Hospitalization and Survival Study in Heart Failure), eplerenone significantly reduced major cardiovascular events versus placebo in 2737 patients with mild symptoms of heart failure and an ejection fraction of <35%, in addition to recommended therapy. However, it is not known whether such benefits were preserved in patients receiving optimal background drug therapy, that is, high doses of angiotensin-converting enzyme inhibitor (ACEi, or angiotensin receptor blocker), ß-blocker, or both drug classes. METHODS AND RESULTS: We further analyzed EMPHASIS-HF according to the use and dose of these background drug classes. Patients receiving ≥ 50% of target dose were considered to be receiving high doses; patients on <50% or no drug comprised the low-dose group. The primary end point of the study (cardiovascular death/heart failure hospitalization), as well as all-cause mortality, was evaluated in this way. The beneficial clinical effects of eplerenone (as observed in the main study) were preserved for the EMPHASIS-HF primary end point in patients receiving higher doses of ACEi or angiotensin receptor blocker, ß-blocker, or both (hazard ratio for eplerenone versus placebo, ACEi/angiotensin receptor blocker: high dose, 0.67; low dose, 0.65; ß-blockers: high dose, 0.55; low dose, 0.72; both ACEi/angiotensin receptor blocker and ß-blocker: high dose, 0.59; low dose, 0.68; P value for interaction 0.80, 0.15, and 0.53, respectively), as well as for all-cause mortality. There were no major safety issues, except a borderline increased risk of hypotension with eplerenone in those on high-dose ACEi or ACEi/ß-blocker. CONCLUSIONS: Eplerenone provides substantial benefit on major events (with an acceptable safety profile) in patients with mild symptoms of systolic heart failure, even in those already receiving high doses of standard background therapies.

Administration-time differences in effects of hypertension medications on ambulatory blood pressure regulation.

Specific features of the 24-h blood pressure (BP) pattern are linked to progressive injury of target tissues and risk of cardiovascular disease (CVD) events. Several studies have consistently shown an association between blunted asleep BP decline and risk of fatal and nonfatal CVD events. Thus, there is growing focus on ways to properly control BP during nighttime sleep as well as during daytime activity. One strategy, termed chronotherapy, entails the timing of hypertension medications to endogenous circadian rhythm determinants of the 24-h BP pattern. Significant and clinically meaningful treatment-time differences in the beneficial and/or adverse effects of at least six different classes of hypertension medications, and their combinations, are now known. Generally, calcium channel blockers (CCBs) are more effective with bedtime than morning dosing, and for dihydropyridine derivatives bedtime dosing significantly reduces risk of peripheral edema. The renin-angiotensin-aldosterone system is highly circadian rhythmic and activates during nighttime sleep. Accordingly, evening/bedtime ingestion of the angiotensin-converting enzyme inhibitors (ACEIs) benazepril, captopril, enalapril, lisinopril, perindopril, quinapril, ramipril, spirapril, trandolapril, and zofenopril exerts more marked effect on the asleep than awake systolic (SBP) and diastolic (DBP) BP means. Likewise, the bedtime, in comparison with morning, ingestion schedule of the angiotensin-II receptor blockers (ARBs irbesartan, olmesartan, telmisartan, and valsartan exerts greater therapeutic effect on asleep BP, plus significant increase in the sleep-time relative BP decline, with the additional benefit, independent of drug terminal half-life, of converting the 24-h BP profile into a more normal dipping pattern. This is the case also for the bedtime versus upon-awakening regimen of combination ARB-CCB, ACEI-CCB, and ARB-diuretic medications. The chronotherapy of conventional hypertension medications constitutes a new and cost-effective strategy for enhancing the control of daytime and nighttime SBP and DBP levels, normalizing the dipping status of their 24-h patterning, and potentially reducing the risk of CVD events and end-organ injury, for example, of the blood vessels and tissues of the heart, brain, kidney, and retina.

Description of antihypertensive use in patients with resistant hypertension prescribed four or more agents.

Data describing the use of recommended antihypertensive agents in the resistant hypertension population are limited. Treatment recommendations for resistant hypertension include maximizing diuretic therapy by using chlorthalidone and/or adding an aldosterone antagonist. Additional recommendations include combining antihypertensive agents from different drug classes. This retrospective cohort study describes antihypertensive use in patients with resistant hypertension defined as the concurrent use of ≥4 antihypertensive agents. Claims data from the Medstat MarketScan Commercial Claims and Encounter database were used to identify patients with resistant hypertension based on International Classification of Diseases, 9th Revision, Clinical Modification (ICD-9-CM) diagnosis codes and National Drug Codes between May 1, 2008 and June 30, 2009. Of the 5 442 410 patients with hypertension in the database, 140 126 met study criteria. The most frequently prescribed antihypertensive classes were angiotensin-converting enzyme inhibitors and/or angiotensin receptor blockers (96.2%), diuretics (93.2%), calcium channel blockers (83.6%), and ß-blockers (80.0%). Only 3.0% and 5.9% of patients were on chlorthalidone or an aldosterone antagonist, respectively. A total of 15.6% of patients were treated with angiotensin-converting enzyme inhibitor plus angiotensin receptor blocker. Our findings demonstrate that frequently prescribed antihypertensive agents for the treatment of resistant hypertension included guideline-recommended first-line agents. However, evidence-based and recommended agents, such as chlorthalidone and aldosterone antagonists, were underused. Moreover, minimally efficacious combinations, such as an angiotensin-converting enzyme inhibitor with an angiotensin receptor blocker, were prescribed at higher rates than evidence-based and recommended agents.

In vivo and in vitro characterization of the novel antiarrhythmic agent SSR149744C: electrophysiological, anti-adrenergic, and anti-angiotensin II effects.

SSR149744C (SSR, 2-butyl-3-[4-[3-(dibutylamino)pro-pyl]benzoyl]-1-benzofuran-5-carboxylate isopropyl fumarate), is a new non-iodinated benzofuran derivative. The aim of this study was to evaluate in vivo its electrophysiological, hemodynamic, and anti-adrenergic properties and to determine its mechanism of action using in vitro studies. In chloralose-anesthetized dogs, SSR149744C (1-10 mg/kg i.v.) prolonged the sinus cycle length, A-H interval, Wenckebach cycle length, atrial effective refractory period (ERP), and atrio-ventricular node ERP in a dose-dependent manner without change of ventricular ERP and HV, QRS, or QTc intervals. Arterial blood pressure and ventricular inotropism were slightly decreased. SSR149744C, which has no or low affinity for alpha 1 and beta 1 adrenergic and angiotensin II AT1 receptors, reduced isoproterenol-induced tachycardia and phenylephrine- or angiotensin II-induced hypertension in anaesthetized dogs. In guinea pig papillary muscle, SSR149744C did not modify the resting potential, action potential amplitude and duration, but reduced the dV/dt max of the depolarization phase in a frequency-dependent manner. In isolated guinea pig cardiomyocytes and transfected CHO cells, SSR149744C (0.01-30 microM) inhibited several potassium currents: IKr (IC50 approximately 10 microM), IKs (IC50 approximately 30 microM), IK(ACh) (IC50 = 0.09 microM), and IKv1.5 (IC50 = 2.7 microM), the L-type calcium current: ICa(L) (IC50 approximately 5 microM) and also the amplitude of [Ca2+]i transient and cell shortening. Therefore, SSR149744C appears to have a multifactorial mechanism of action, which combines the blockade of several ion channels with the inhibition of responses of alpha 1 and beta 1 adrenergic as well as AT1 receptor stimulation. Like amiodarone, SSR149744C possesses the pharmacological effects of class I, II, III, and IV antiarrhythmic agents, which may confer upon this new drug a strong antiarrhythmic potential without ventricular proarrhythmia and iodine-related amiodarone-like side-effects.

Sympathetic innervation of mammary glands mediates suckling-induced reflex inhibition of milk yield in rats.

Previous work has shown that physiologic activation of the sympathetic system may inhibit milk yield (ME) in rats. Thus, adrenal catecholamines (CAs) are released by suckling, but it is not known whether such inhibition results also from reflex activation by the same stimulus of neural sympathetics upon the mammary gland. The present experiments were designed to determine whether suckling inhibits ME induced by oxytocin (OT) in the urethane-anesthetized lactating rat, and whether such inhibition results from adrenal and/or neurally released CAs. Rats were isolated (6 h) from their pups and then anesthetized. OT (0.8 mU every 2 min) was administered intravenously to the mothers during suckling. Rats were either chronically implanted with cannulae into the lateral cerebral ventricles (intracerebroventricularly), bilaterally adrenalectomized (ADX), hypophysectomized (HX), spinal cord transected (SCT: T3-T4), or had the nipple area (NA) locally anesthetized before suckling. MEs were low in control, sham, ADX and HX rats, but not in rats given the beta-adrenergic blocker propranolol (PROP; intravenously or intracerebroventricularly injected), nor in SCT, NA or PROP-HX rats. As revealed by ductal resistance measurements as an indicator of ductal tone, suckling-induced inhibition of ME was due to ductal constriction within the mammary glands. These effects of suckling, however, could be prevented by prior activation of ductal mechanoreceptors. Together, these results indicate that suckling inhibits ME through the reflex activation of neurally mediated central beta-adrenergic mechanisms, and that these effects, in turn, can be regulated by ductal mechanoreceptor activation.

Chronopharmacologic considerations when treating the patient with hypertension: a review.

Recognition of the existence of circadian variation in exacerbation of cardiovascular disease may have relevance to clinical use of cardioactive agents. Physiologic rational for the chronobiology of cardiac disease exists and can provide a basis on which to examine the efficacy of agents to manage cardiac disease. The use of 24-hour ambulatory blood pressure monitoring (ABPM) devices have advanced our ability to describe the interplay of chronobiologic rhythms and pharmacodynamic response to antihypertensive medications. This review summarizes the studies evaluating the use of various antihypertensive medications in the context of using 24-hour blood pressure monitoring devices. The studies are described in an attempt to increase awareness of chronobiology and potential implications of designing chronotherapeutic regimens.