Medium-term effects of beta-blockade on left ventricular mechanics: a double-blind, placebo-controlled comparison of nebivolol and atenolol in patients with ischemic left ventricular dysfunction

The controversial role of beta-blockers in heart failure with preserved ejection fraction

Beta-blocker (BB) therapy is a main pillar in treating patients with heart failure and reduced ejection fraction and has shown a prognostic benefit. However, evidence for application of BB in heart failure with preserved ejection fraction (HFpEF), especially in the absence of coronary artery disease, atrial fibrillation or arterial hypertension, is scarce. HFpEF is characterized by elevations in left atrial pressure and reduced compliance of the left ventricle leading to a hampered increase of cardiac output (CO) during exercise, which results in exertional dyspnea. This may be due to either a limited increase in stroke volume or reduced chronotropy during physical activity. We critically discuss the pathophysiological background of HFpEF, current data on BB in heart failure therapy, as well as the potential benefits and harms of BB therapy in HFpEF. Furthermore, we argue that non-cardio selective BB with peripheral activity to reduce afterload may be more suitable in this population than cardio-selective BB. Although preliminary data on BB in HFpEF are available, multicenter prospective trials to assess a reduction of cardiovascular morbidity are warranted. Future trials need to focus on phenotyping HFpEF patients and assess who may benefit most from tailored BB therapy.

Nebivolol versus Carvedilol or Metoprolol in Patients Presenting with Acute Myocardial Infarction Complicated by Left Ventricular Dysfunction

OBJECTIVE

The aim of this study was to evaluate the efficacy of nebivolol, carvedilol or metoprolol succinate on the outcome of patients presenting with acute myocardial infarction (AMI) complicated by left ventricular dysfunction.

SUBJECTS AND METHODS

Patients (n = 172, aged 28-87 years) with AMI and left ventricular ejection fraction ≤0.45 were randomized to the nebivolol (n = 55), carvedilol (n = 60) and metoprolol succinate (n = 57) groups. Baseline demographic and clinical characteristics and composite event rates of nonfatal MI, cardiovascular mortality, hospitalization due to unstable angina pectoris or heart failure, stroke or revascularization during the 12-month follow-up were compared among the groups using the x03C7;2 test, t test or log-rank test as appropriate.

RESULTS

Baseline demographic and clinical characteristics were similar in the three groups. The composite end point during follow-up was lower in the patients treated with nebivolol than those treated with metoprolol (14.5 vs. 31.5%; p = 0.03). However, event rates were similar between the patients treated with carvedilol and those treated with the metoprolol (20.3 vs. 31.5%, p > 0.05) and between the patients treated with nebivolol and carvedilol (14.5 vs. 20.3%, p > 0.05).

CONCLUSION

The patients treated with nebivolol experienced 12-month cardiovascular events at a lower rate than those treated with metoprolol succinate. However, event rates were similar between the carvedilol and the metoprolol succinate groups and between the nebivolol and the carvedilol groups.

Clinical and economic aspects of the use of nebivolol in the treatment of elderly patients with heart failure

Heart failure is a common and disabling condition with morbidity and mortality that increase dramatically with advancing age. Large observational studies, retrospective subgroup analyses and meta-analyses of clinical trials in systolic heart failure, and recently published randomized studies have provided data supporting the use of beta-blockers as a baseline therapy in heart failure in the elderly. Despite the available evidence about beta-blockers, this therapy is still less frequently used in elderly compared to younger patients. Nebivolol is a third-generation cardioselective beta-blocker with L-arginine/nitric oxide-induced vasodilatory properties, approved in Europe and several other countries for the treatment of essential hypertension, and in Europe for the treatment of stable, mild, or moderate chronic heart failure, in addition to standard therapies in elderly patients aged 70 years old or older. The effects of nebivolol on left ventricular function in elderly patients with chronic heart failure (ENECA) and the study of effects of nebivolol intervention on outcomes and rehospitalization in seniors with heart failure (SENIORS) have been specifically aimed to assess the efficacy of beta-blockade in elderly heart failure patients. The results of these two trials demonstrate that nebivolol is well tolerated and effective in reducing mortality and morbidity in older patients, and that the beneficial clinical effect is present also in patients with mildly reduced ejection fraction. Moreover, nebivolol appears to be significantly cost-effective when prescribed in these patients. However, further targeted studies are needed to better define the efficacy as well as safety profile in frail and older patients with comorbid diseases.

Atenolol is inferior to metoprolol in improving left ventricular function and preventing ventricular remodeling in dogs with heart failure

OBJECTIVES

beta-Blockers are standard therapy for patients with heart failure (HF). This study compared the effects of chronic monotherapy with 2 different beta(1)-selective adrenoceptor blockers, namely atenolol and metoprolol succinate, on left ventricular (LV) function and remodeling in dogs with coronary microembolization-induced HF [LV ejection fraction (EF) 30-40%].

METHODS

Twenty HF dogs were randomized to 3 months of therapy with atenolol (50 mg once daily, n = 6), metoprolol succinate (100 mg, once daily, n = 7) or to no therapy (control, n = 7). LV EF and volumes were measured before initiating therapy and after 3 months of therapy. The change (Delta) in EF and volumes between measurements before and after therapy was calculated and compared among study groups.

RESULTS

In controls, EF decreased and end-systolic volume increased. Atenolol prevented the decrease in EF and the increase in ESV. In contrast, metoprolol succinate significantly increased EF and decreased end-systolic volume. DeltaEF was significantly higher and Deltaend-systolic volume significantly lower in metoprolol succinate-treated dogs compared to atenolol-treated dogs (EF: 6.0 +/- 0.86% vs. 0.8 +/- 0.85%, p < 0.05; end-systolic volume: -4.3 +/- 0.81 ml vs. -1 +/- 0.52 ml, p <0.05).

CONCLUSIONS

In HF dogs, chronic therapy with atenolol does not elicit the same LV function and remodeling benefits as those achieved with metoprolol succinate.

Nebivolol: third-generation β-blockade

Nebivolol is a third generation beta-blocker. It is highly selective for the beta1-adrenoceptor, and has additional nitric oxide-mediated vasodilating and antioxidant properties, along with a favourable metabolic profile. Nebivolol is well tolerated by patients with hypertension and heart failure. Although several smaller studies were conducted with nebivolol in hypertensive patients, no large randomised clinical trials have been performed to prove efficacy on hard clinical end points. In patients with heart failure, a large mortality/morbidity trial was conducted, and nebivolol was shown to reduce the composite end point of mortality and hospitalisations. Nebivolol is registered, in Europe, for mild-to-moderate, uncomplicated hypertension and mild-to-moderate heart failure; and outside Europe, for hypertension. This review describes experimental and clinical data regarding this selective beta-blocker with vasodilating and antioxidant effects.

Nebivolol for heart failure in the elderly

Recent analyses in the temporal trends of mortality and hospitalization in patients with chronic heart failure showed marginal changes in the last 20 years, particularly in the elderly. According to the Euro Heart Survey program and other observational reports, only 37-50% of patients with heart failure are treated with beta-blockers, with a dosage that is approximately half the target dose of clinical trials. The most frequent reason for the limited use of beta-blockers and the suboptimal doses prescribed, is age greater than 70 years. Only two multicenter, double-blind, randomized, placebo-controlled, parallel group trials; the Effects of Nebivolol on Left Ventricular Function in Elderly Patients with Chronic Heart Failure (ENECA) and the Study of Effects of Nebivolol Intervention on Outcomes and Rehospitalization Seniors with Heart Failure (SENIORS), both with nebivolol, have been specifically aimed to assess the efficacy of beta-blockade in elderly heart failure patients. The results of such trials demonstrated that the drug is well tolerated and effective in reducing mortality and morbidity, and that the beneficial clinical effect is independent of the baseline ejection fraction.

Nebivolol: a novel beta-blocker with nitric oxide-induced vasodilatation

Nebivolol is a novel beta₁-blocker with a greater degree of selectivity for beta₁-adrenergic receptors than other agents in this class and a nitric oxide (NO)-potentiating, vasodilatory effect that is unique among beta-blockers currently available to clinicians (nebivolol is approved in Europe and is currently under review in the US). A NO-potentiating agent such as nebivolol may have an important role in hypertensive populations with reduced endothelial function such as diabetics, African-Americans and those with vascular disease. Nebivolol is a racemic mixture with beta-blocker activity residing in the d-isomer; in contrast, l-nebivolol is far more potent in facilitating NO release. Nebivolol is unique among beta-blockers in that, at doses <10 mg, it does not inhibit the increase in heart rate normally seen with exercise. The efficacy of nebivolol has been tested successfully in clinical trials against other agents including other beta-blockers, angiotensin-converting enzyme-inhibitors and calcium channel antagonists in patients with hypertension, angina, and congestive heart failure. The tolerability of nebivolol has been shown to be superior to that of atenolol and metoprolol. In controlled clinical trials, nebivolol has a side effect profile that is similar to placebo, in particular as it relates to fatigue and sexual dysfunction. This article will review published clinical data regarding this cardioselective beta-blocker.

Nebivolol: a third-generation beta-adrenergic blocker

OBJECTIVE

To describe the pharmacologic and pharmacokinetic properties of a new beta-adrenergic blocker, nebivolol, and review the literature evaluating its efficacy in the treatment of hypertension and heart failure.

DATA SOURCES

Articles were identified through searches of MEDLINE (1996-May 2006) and International Pharmaceutical Abstracts (1970-May 2006), using the key word nebivolol. Additional references were selected from the bibliographies of the articles cited. Searches were not limited by language, time, or human subject.

STUDY SELECTION AND DATA EXTRACTION

Preclinical studies evaluating the pharmacologic and pharmacokinetic properties of nebivolol in humans were selected for review. Randomized, controlled, blinded clinical trials assessing the efficacy of nebivolol for the treatment of hypertension and heart failure were also included.

DATA SYNTHESIS

Preclinical data have established nebivolol as a third-generation beta-adrenergic blocker, as it possesses vasodilatory properties that contribute to its hemodynamic effects beyond those achieved at beta-adrenergic receptors. Short-term, randomized, controlled clinical trials have shown nebivolol to be as effective as other antihypertensive therapies at lowering blood pressure. One long-term trial showed a significant reduction in death and hospital admissions for cardiovascular causes when nebivolol was compared with placebo in patients with heart failure (31.1% vs 65.3%; HR 0.86; 95% CI 0.74 to 0.99).

CONCLUSIONS

Nebivolol is a novel beta-adrenergic blocker that possesses unique pharmacologic properties, compared with other agents in its class. Nebivolol appears to be as effective as other antihypertensive agents at lowering blood pressure and possesses benefits for patients with heart failure. Additional studies are needed to address the long-term benefits of nebivolol for hypertension, to compare nebivolol with other beta-adrenergic blockers for heart failure, and to investigate the clinical relevance of nitric oxide-mediated vasodilation.

Pharmacological Mechanisms of Clinically Favorable Properties of a Selective β1-Adrenoceptor Antagonist, Nebivolol

Nebivolol is a racemic mixture of d- and l-enantiomers. The drug is characterized by beta(1)-adrenoceptor selectivity and long-acting beta-blockade exerted predominantly by d-enantiomer. Nebivolol is devoid of intrinsic sympathomimetic activity and has no relevant membrane stabilizing action. Antiproliferative properties of nebivolol were demonstrated in endothelial and smooth muscle cell cultures. Infusion of nebivolol causes a vasodilation in all vascular beds by endothelial-dependent mechanism involving stimulation of beta(3)-adrenoceptors as well as by endothelial-independent mechanism. Nebivolol possesses not only direct vasodilator properties but also augments the action of endothelium-dependent vasodilators. The antioxidant property of nebivolol can at least in part explain why treatment with this drug enhances eNOS activity and minimizes the reperfusion-induced myocardial injury. The systemic effects of nebivolol in humans have an unusual hemodynamic profile. In contrast to traditional beta-adrenoceptor antagonists, nebivolol reduces preload and afterload due to systemic vasodilation and improves arterial distensibility. At 5 mg daily nebivolol effectively reduces systolic and diastolic blood pressure over a 24-h period. During treatment with nebivolol arterial pressure follows the natural circadian rhythm. Trough-to-peak ratio for nebivolol is 0.9. It has been demonstrated in numerous placebo-controlled studies that exercise tolerance is not reduced during nebivolol therapy. By chronic administration to patients with left ventricular dysfunction nebivolol increases myocardial contractility. Nebivolol produced no significant changes in lipid levels, insulin sensitivity or glucose tolerance. These findings make nebivolol a promising therapeutic tool for the treatment of arterial hypertension and chronic heart failure.

??-Adrenoceptor Antagonists in Elderly Patients with Chronic Heart Failure

Chronic heart failure (CHF) is a common and disabling condition with an incidence and prevalence that increase sharply with age. The median age of presentation of new heart failure cases is > 75 years. Effective treatments, including beta-adrenoceptor antagonists, have been proven in randomised, controlled trials. The average age in these placebo-controlled mortality and morbidity studies of beta-adrenoceptor antagonists in heart failure has, however, been < 63 years, and all patients with an ejection fraction > or = 40% were excluded. This lack of a representative sample of elderly patients with heart failure has raised concerns about extrapolating the available evidence for beta-adrenoceptor antagonists to a more elderly heart failure population. Beta-adrenoceptor antagonists may have a less beneficial effect or even an adverse effect in elderly heart failure patients. There is evidence that beta-adrenoceptor antagonists are less frequently prescribed in elderly CHF patients, and that this lack of treatment is associated with impaired outcomes. Establishing which beta-adrenoceptor antagonists, if any, are effective in elderly CHF is therefore of extreme importance. The elderly have a reduced cardiovascular reserve and may be less tolerant of the introduction of a vasoconstricting beta-adrenoceptor antagonist. In addition, the higher proportion of elderly CHF patients with relatively preserved systolic function (for which no treatment has been proven to reduce mortality and morbidity) means that we cannot say with certainty that beta-adrenoceptor antagonists have been proven to be effective in a general elderly CHF population. Third-generation beta-adrenoceptor antagonists with vasodilating actions in addition to their beta-adrenoceptor antagonist effects may offer several theoretical advantages over earlier beta-adrenoceptor antagonists for elderly CHF patients. Three of this class (carvedilol, bucindolol and nebivolol) have been evaluated with respect to their efficacy in reducing mortality and morbidity in CHF, and only two of these (carvedilol and nebivolol) had a proven outcome benefit in a properly powered randomised, controlled trial. Only the Study of the Effects of Nebivolol Intervention on Outcomes and Rehospitalisation in Seniors with Heart Failure (which used the vasodilating third-generation beta-adrenoceptor antagonist nebivolol) has prospectively investigated the treatment of CHF in elderly patients, including those with preserved systolic function, and demonstrated a significant reduction in the risk of death or cardiovascular hospitalisation. In conclusion, prescribers are advised that nebivolol should be preferred in elderly patients with CHF, because of its proven efficacy in a representative group of elderly CHF patients.

Effects of nebivolol versus carvedilol on left ventricular function in patients with chronic heart failure and reduced left ventricular systolic function

BACKGROUND

Beta-adrenoceptor antagonist (beta-blocker) therapy results in a significant improvement in left ventricular (LV) systolic function and prognosis in patients with chronic heart failure. Both carvedilol and nebivolol produce hemodynamic and clinical benefits in chronic heart failure, but it is unknown whether their peculiar pharmacologic properties produce different effects on LV function.

OBJECTIVE

To assess the effects on LV function of nebivolol compared with carvedilol in patients with chronic heart failure and reduced LV systolic function.

METHODS

Seventy patients with a LV ejection fraction <or=40% and in New York Heart Association (NYHA) functional class II or III were randomly assigned to receive carvedilol or nebivolol therapy for 6 months. At baseline and after 6 months of treatment, all patients were assessed clinically and by biochemical and hematological investigation, ECG, 24-hour Holter monitoring, echocardiogram, measurement of ventilatory function, and a 6-minute walk test.

RESULTS

Compared with baseline values LV end-systolic volume decreased and LV ejection fraction increased in both the carvedilol (from 79 +/- 38mL to 73 +/- 43mL and from 33% +/- 6% to 37% +/- 11%) and the nebivolol group (from 72 +/- 35mL to 66 +/- 32mL and from 34% +/- 7% to 38% +/- 10%), although the between-group differences were not statistically significant. ECG data showed a decrease in resting HR in both groups (from 83 +/- 20 bpm to 66 +/- 11 bpm for carvedilol and from 81 +/- 15 bpm to 65 +/- 11 bpm for nebivolol; p < 0.001 vs baseline for both groups) but no difference in the PQ, QRS, and QT intervals. Hematologic (in particular, N-terminal pro-brain natriuretic peptide), Holter monitoring (with the exception of HR), and respiratory functional data did not show any significant variation in either group after 6 months' therapy. SBP and DBP decreased in both groups. A small reduction in mean NYHA functional class from baseline was seen in both groups (from 2.5 +/- 0.5 to 2.2 +/- 0.5 for carvedilol [p < 0.05] and from 2.3 +/- 0.4 to 2.2 +/- 0.5 for nebivolol [not significant]). The 6-minute walk test showed a trend toward an increase in the walking distance in both groups. During 6 months of treatment no significant differences in adverse events were observed between the groups.

CONCLUSION

Nebivolol is as effective as carvedilol in patients with symptomatic chronic heart failure and reduced LV systolic function.

Effects of nebivolol on left ventricular function in elderly patients with chronic heart failure: results of the ENECA study

AIM

To examine the effect of the beta(1)-selective beta-blocker nebivolol, administered as add-on therapy, on left ventricular function in 260 elderly patients (>65 years) with chronic heart failure (CHF).

METHODS

The principal inclusion criteria were (1) NYHA class II-IV CHF and (2) a left ventricular ejection fraction (LVEF) <= 35%. The primary end-point was the change in LVEF in response to nebivolol treatment for 8 months.

RESULTS

Baseline LVEF values in the two groups were as follows: nebivolol 25.41+/-7.09% and control 26.41+/-5.55%. LVEF improved significantly (p=0.027) more in the nebivolol group (6.51+/-9.15%) than in the control group (3.97+/-9.20%), the relative improvement (percentage increase in the initial value) being 35.70+/-57.62% in the nebivolol group and 19.19+/-40.96% (p=0.008) in the placebo group. Examination of different subgroups did not reveal any heterogeneity in the effects of nebivolol treatment vs. placebo treatment. There were no significant differences between the nebivolol and placebo groups as concerns the changes in clinical status, quality of life, or safety parameters.

CONCLUSION

The findings of the ENECA study confirmed that nebivolol significantly improved cardiac function and proved to be safe and well tolerated in elderly patients with signs of CHF and an impaired LVEF.

Beta-blocker treatment of patients with diastolic heart failure and arterial hypertension. A prospective, randomized, comparison of the long-term effects of atenolol vs. nebivolol

We compared the effects of 6 months administration of atenolol or nebivolol on resting and exercise hemodynamic parameters and maximal exercise capacity, in 26 patients with hypertension and left ventricular (LV) diastolic dysfunction (ejection fraction >50%, end-diastolic diameter <60 mm and increased pulmonary wedge pressure at rest and/or at peak exercise). Both atenolol and nebivolol administration was associated with a significant decrease in the resting and peak exercise heart rate and blood pressure and in LV mass, with an increase in the E/A ratio. This latter effect was greater with nebivolol. Nebivolol was associated with an increase in the peak VO(2), VO(2) at the anaerobic threshold and with a decrease in the VE/VCO(2) ratio. With regards to the hemodynamic parameters, compared to patients on atenolol, those on nebivolol showed a lower reduction in the cardiac index, a greater increase in the stroke volume index and a decline in the mean pulmonary artery pressure and pulmonary wedge pressure, both at rest and peak exercise. Thus, although the two beta-blockers have a similar antihypertensive action, nebivolol administration was associated with a greater hemodynamic improvement, compared to atenolol.

Beta-blockade in hypertension and congestive heart failure

Hypertension is common and increases the risk of death from coronary artery disease and cerebral vascular disease. The reason for treating hypertension is to prevent the long-term complications of this disorder. Many studies of antihypertensive therapy have produced only modest reductions in coronary events; in particular, with the use of beta-blockers. Clinical trials and meta-analyses have shown a lesser effect of these drugs on primary prevention of coronary events, cardiovascular and total mortality with respect to other antihypertensive approaches based on the use of low-dose diuretic therapy, especially in the elderly, even if the reduction of stroke and heart failure (HF) were similar. New beta-blockers with vasodilating properties due to the capacity to enhance the release of endothelial nitric oxide, then lessening a contributory mechanism to the pathogenesis of atherosclerosis as endothelial damage and dysfunction, seem to possess considerable potential in the treatment of hypertension, particularly in terms of improvement of cardiovascular outcome of patients. In HF, there is now considerable interest in the therapeutic use of beta-blockade. Some recent clinical trials have demonstrated conclusive evidence of the beneficial effects of beta-blocker therapy on survival in chronic HF. As a result of these data, beta-blocker therapy has become part of standard therapy for patients with chronic HF, in addition to angiotensin-converting enzyme-inhibitors and diuretics. The treatment is, in general, well tolerated. There are, however, some unanswered questions. One is whether some beta-blockers may be better than others. The major mortality benefit is probably a class-effect of beta1-adrenoceptor blockade, but the differences between beta-blockers might be clinically relevant. For example, it is under debate whether ancillary properties of some beta-blockers, such as the capability of exerting antioxidant effects or enhancing the nitric oxide production, may contribute to the clinical effects of these drugs. Future clinical trials will report over the next few years and help to answer the question about differences in mortality effects among types of beta-blocking agents, thus correctly defining the precise role of these drugs in the wide spectrum of cardiovascular disease.

Effect of beta 1 blockade with atenolol on progression of heart failure in patients pretreated with high-dose enalapril

BACKGROUND

The survival benefit of beta-blocker treatment in patients with heart failure has been established in recent trials. Yet, the impact of beta-blockers added on high dose angiotensin converting enzyme inhibitors has not been reported.

AIMS

To investigate the effect of atenolol, a hydrophilic, selective beta1-adrenergic antagonist, added on enalapril 40 mg/day in patients with advanced left ventricular dysfunction in a double-blind placebo-controlled trial.

METHODS

One hundred and nineteen patients with class II or III heart failure, left ventricular ejection fraction < or = 25% and treatment with 40 mg enalapril daily were given an initial challenge dose of atenolol 12. 5 mg. One hundred patients (54 with idiopathic, 28 with ischemic, 18 with other dilated cardiomyopathy) tolerated challenge and were randomized to atenolol (maintenance dose 89+/-11 mg/day, range 50-100 mg/day) or placebo. The primary endpoint was combined worsening heart failure or death within 2 years, the secondary endpoint was hospitalization for cardiac events.

RESULTS

After 395+/-266 days interim analysis revealed a significant difference between the atenolol and placebo group (log rank P<0.01) and the trial was concluded. Twenty-seven patients had developed worsening heart failure (8 in the atenolol group vs. 19 in the placebo group) and 13 patients had died (5 in the atenolol vs. 8 in the placebo group). Overall there were 23 hospitalizations for cardiac events (6 in the atenolol group vs. 21 in the placebo group, P=0.07); 17 hospitalizations were due to worsening heart failure (5 in the atenolol group, 12 in the placebo-group, P=0.05) and 10 due to arrhythmias (1 in the atenolol group vs. 9 in the placebo group, P<0.01)

CONCLUSIONS

The data suggest that in patients with advanced left ventricular dysfunction, beta-blockers can provide substantial benefits supplementary to that already achieved with high dose enalapril treatment.

Nebivolol in the management of essential hypertension: a review

Nebivolol is a lipophilic beta1-blocker. It is devoid of intrinsic sympathomimetic or membrane stabilising activity but appears to have nitric oxide-mediated vasodilatory effects. Nebivolol is administered as a racemic mixture of equal proportions of d- and l-enantiomers. The drug does not significantly influence glucose or plasma lipid metabolism and appears to have a protective effect on left ventricular function. At the recommended dosage (5 mg once daily) nebivolol reduces resting diastolic blood pressure as effectively as standard therapeutic dosages of atenolol, metoprolol, lisinopril and nifedipine, as shown in comparative trials. Nebivolol reduced blood pressure significantly more than enalapril 10 mg daily in the short but not the long term, although the enalapril dose may not have been optimal. Nebivolol has an additive effect in combination with hydrochlorothiazide. Standing blood pressure and/or mean 24-hour ambulatory blood pressure is significantly and similarly reduced with nebivolol, atenolol or nifedipine. Nebivolol tended to prevent increases in early morning blood pressure better than nifedipine. Overall response rates to nebivolol therapy (a decrease in sitting/supine diastolic blood pressure to < or = 90 mm Hg or a 10% or > or = 10 mm Hg fall in diastolic blood pressure) ranged from 58 to 81% after 4 to 52 weeks' treatment. In comparative studies, response rates were greater in nebivolol than in enalapril or metoprolol recipients, but not significantly different from those in atenolol or nifedipine recipients. Nebivolol 5 mg once daily is well tolerated in patients with hypertension. Adverse events are infrequent, transient and mild to moderate. Those reported most often include headache, fatigue, paraesthesias and dizziness. Several studies reported no signs of orthostatic hypotension with nebivolol. Comparative trials revealed no significant differences between the frequency and severity of adverse events in patients receiving nebivolol, atenolol, enalapril or placebo; however, the overall incidence of adverse events was greater with nifedipine or metoprolol. Some atenolol or enalapril, but not nebivolol, recipients reported impotence or decreased libido during therapy.

CONCLUSION

Current evidence indicates that nebivolol 5 mg once daily is a well tolerated beta-blocker, which is as effective as once daily atenolol and other classes of antihypertensive agents. It may therefore be recommended as a useful alternative first-line treatment option for the management of patients with mild to moderate uncomplicated essential hypertension.

Ejection fraction improvement by beta-blocker treatment in patients with heart failure: an analysis of studies published in the literature

Because ejection fraction (EF) is one of the most important predictors of survival in patients with left ventricular (LV) dysfunction and because Packer showed a large reduction in mortality figures with carvedilol, in contrast to former studies with bisoprolol and metoprolol, we investigated if this difference in survival may be related to a difference in improvement of LV function by different beta-blockers. We searched the MEDLINE database and all reference lists of articles obtained through the search for the relation between beta-blocker treatment and improvement in EF. Forty-one studies met the criteria and we added two of our own studies. Four hundred and fifty-eight patients were treated with metoprolol with a mean follow-up of 9.5 months and a mean increase in EF of 7.4 EF units. One thousand thirty patients were treated with carvedilol with a mean follow up of 7 months and a mean increase in EF of 5.7 EF units. One hundred ninety-nine patients were treated with bucindolol with a mean follow-up of 4 months and a mean increase in EF of 4.6 EF units. Several small studies with nebivolol, atenolol, and propranolol were also studied and, when combined, the mean increase in EF was 8.6 EF units. When patients with idiopathic and ischemic cardiomyopathies were compared, the average increase in EF units was 8.5 vs. 6.0, respectively. The use of beta-blocker treatment in heart failure patients, irrespective of the etiology, improved LV function in almost all studies and it appears that the differences among beta-blockers and among etiologies is small and probably insignificant. However, there is a difference in survival rate when the various beta-blockers are compared, suggesting that mechanisms other than improvement of LV function by beta-blockers are responsible for the difference in survival.

Nebivolol in the treatment of cardiac failure: a double-blind controlled clinical trial

BACKGROUND

Nebivolol is a highly cardioselective long-acting beta-blocker with vasodilating properties, which acts in part via the endothelial L-arginine/nitric oxide pathway. As an antihypertensive drug it is effective in once-daily dosage. Nebivolol has previously been shown to improve left ventricular function in patients with cardiac impairment.

METHODS AND RESULTS

This paper reports a double-blind randomized trial comparing, in patients with heart failure, once-daily nebivolol 2.5 or 5.0 mg (initiated in all at 2.5 mg) with placebo on a constant background of digitalis plus diuretic. There was with nebivolol no overall deterioration of cardiac function or cardiac symptoms, and especially not of exercise capacity, in comparison with placebo. One patient on nebivolol 2.5 mg developed hypotension and pulmonary edema, and one patient on nebivolol 5 mg, bradycardia. All the remaining patients continued with unchanged diuretic and digitalis dosage. Nebivolol was accompanied by a trend toward clinical and functional improvement; rather better results were obtained with 2.5 than 5.0 mg.

CONCLUSIONS

In view of increasing interest in beta-blockade in heart failure, nebivolol merits further study in this context. The capacity of nebivolol to enhance endothelial nitric oxide production appears potentially attractive.

Pharmacological properties of nebivolol in man

OBJECTIVES

The aims of the present study were to determine (1) the beta 1-blocking potency and (2) the beta 1-adrenoceptor selectivity of nebivolol in man after repeated dosing (7 days) compared with that after a single oral intake and with that after atenolol for 7 days. In addition, it was investigated whether (3) nebivolol has alpha 1-blocking properties which might at least in part explain the vasodilating property of the compound.

METHODS

Twelve healthy subjects were randomized in an open, two-way cross-over study. beta 1-Blocking potency and beta 1-adrenoceptor selectivity of nebivolol 5 mg once daily (o.d.) were compared with those of atenolol at three doses (25, 50 and 100 mg) o.d. Measurements were performed after 1 and 7 days of drug intake. beta 1-Adrenoceptor potency was assessed by the percentage decrease in exercise-induced tachycardia (delta EIT) during beta-blockade. beta 1-Selectivity of nebivolol and atenolol were investigated using the heart rate response to isoprenaline at equipotent beta 1-blocking dosages of both drugs. alpha 1-Blockade of nebivolol was measured using the phenylephrine dose-response test.

RESULTS

delta EIT after a single oral dose of nebivolol 5 mg (10%) was significantly smaller than after nebivolol 5 mg o.d. for 7 days (15%). After 1 week of treatment no difference was seen in delta EIT between nebivolol 5 mg o.d. and atenolol 25 mg o.d. (16%). At these dosages the suppression in isoprenaline-induced tachycardia by both drugs did not differ (CD20 ratio 1.7). In contrast to atenolol 25 mg, after 1 week of nebivolol 5 mg o.d., blood pressure decreased. This decrease averaged 10% and-like in a study with hypertensive patients-was similar with that after atenolol 100 mg o.d. None of the phenylephrine test parameters changed from pre-study values after nebivolol.

CONCLUSIONS

beta 1-Blockade of nebivolol 5 mg is larger after repeated dosing than after a single oral intake. After once daily repeated dosing nebivolol 5 mg and atenolol 25 mg are equipotent in beta 1-antagonism. No difference in beta 1-selectivity is observed between the two drugs. Nebivolol has no additional alpha 1-blocking property, which may at least in part explain its vasodilating effect.