Are tolerability concerns a class effect of beta-blockers in treating patients with hypertension?

Insights on β-blockers for the treatment of hypertension: A survey of health care practitioners

A quantitative survey was completed by 103 primary care physicians (PCPs) and 59 cardiologists who regularly prescribed β-blockers to assess knowledge and use of this heterogeneous drug class for hypertension. More cardiologists than PCPs chose β-blockers as initial antihypertensive therapy (30% vs 17%, P < 0.01). Metoprolol and carvedilol were the most commonly prescribed β-blockers. Cardiologists rated "impact on energy" and "arterial vasodilation" as more important than PCPs (P < 0.05/<0.01, respectively). Awareness of vasodilation was greater for carvedilol (52%) than nebivolol (31%). Association between β-blockers and clinical variables included nebivolol with β₁ -selectivity, nebivolol and carvedilol with vasodilation and efficacy in older patients and African Americans, metoprolol with heart rate reduction, and atenolol and metoprolol with weight gain and hyperglycemia. Physicians preferred prescribing β-blockers with lower risk of incident diabetes. Clinical practice guidelines influenced physician prescribing more than formularies or performance metrics. This survey captures physicians' perceptions/use of various β-blockers and clinically relevant knowledge gaps.

The Role of Ivabradine in Cardiac Rehabilitation in Patients With Recent Coronary Artery Bypass Graft

BACKGROUND

Little is known about ivabradine in cardiac rehabilitation in patients with coronary artery bypass graft (CABG).

METHODS

In this prospective, randomized study, suitable patients admitted for cardiac rehabilitation after recent CABG were randomized to ivabradine 5 mg twice a day + standard medical therapy including bisoprolol 1.25 mg once daily (group I-BB, n = 38) or standard medical therapy including bisoprolol 2.5 to 3.75 mg once daily (group BB, n = 43). Patients were evaluated at admission, discharge, and 3 months. The primary end point was improvement in functional status, and other end points were improvement in diastolic function and recovery of systolic function. End points were assessed by distance covered in 6-minute walking test (6MWT), percentage with normal diastolic function, and percentage increase in left ventricular ejection fraction (LVEF).

RESULTS

Cardiac rehabilitation improved functional capacity in both groups. In group BB, distances covered in the 6MWT at admission, discharge, and 3 months were 215 ± 53, 314 ± 32, and 347 ± 42 m, respectively. Corresponding distances in group I-BB were 180 ± 91, 311 ± 58, and 370 ± 55 m. Normal diastolic function was restored in I-BB patients, increasing from 24% at admission to 50% and 79% at discharge and 3 months; in BB patients, it decreased from 23% to 19% and 16%. The LVEF improved in I-BB patients, from 57% ± 3% at admission to 62% ± 4% at discharge and 66% ± 3% at 3 months, while remaining unchanged in BB patients (57% ± 3%, 59% ± 4%, and 59% ± 3%).

CONCLUSION

Adding ivabradine to low-dose bisoprolol during cardiac rehabilitation in patients with CABG improved functional capacity, enhanced recovery of systolic function, and reduced diastolic dysfunction.

Efficacy and safety of nebivolol and valsartan as fixed-dose combination in hypertension: a randomised, multicentre study

BACKGROUND

The fixed-dose combination of any two antihypertensive drugs from different drug classes is typically more effective in reducing blood pressure than a dose increase of component monotherapy. We assessed the efficacy and safety of a fixed-dose combination of a vasodilating β blocker (nebivolol) and an angiotensin II receptor blocker (valsartan) in adults with hypertension.

METHODS

We did an 8-week, phase 3, multicentre, randomised, double-blind, placebo-controlled, parallel-group trial at 401 US sites. Participants (age ≥18 years) with hypertension but with blood pressure less than 180/110 mm Hg were randomly assigned (2:2:2:2:2:2:2:1) by a 24-h interactive web response system in blocks of 15 to 4 weeks of double-blind treatment with nebivolol and valsartan fixed-dose combination (5 and 80 mg/day, 5 and 160 mg/day, or 10 and 160 mg/day), nebivolol (5 mg/day or 20 mg/day), valsartan (80 mg/day or 160 mg/day), or placebo. Doses were doubled in weeks 5-8; results are reported according to the final dose. Participants and research staff were masked to treatment allocation. The primary and key secondary endpoints were changes from baseline to week 8 in diastolic and systolic blood pressure, respectively. The primary statistical comparison was between the highest fixed-dose combination dose and the highest monotherapy doses; lower doses were then compared if this comparison was positive (Hochberg method for multiple testing). Efficacy analyses were by intention to treat. Safety assessments included monitoring of adverse events. Continuous efficacy parameters were analysed using an ANCOVA model; binary outcomes were analysed using a logistic regression model. This study is registered with ClinicalTrials.gov, NCT01508026.

FINDINGS

Between Jan 6, 2012, and March 15, 2013, 4161 patients were randomly assigned (277 to placebo and 554-555 to each active comparator group), 4118 of whom were included in the primary analysis. At week 8, the fixed-dose combination 20 and 320 mg/day group had significantly greater reductions in diastolic blood pressure from baseline than both nebivolol 40 mg/day (least-squares mean difference -1·2 mm Hg, 95% CI -2·3 to -0·1; p=0·030) and valsartan 320 mg/day (-4·4 mm Hg, -5·4 to -3·3; p<0·0001); all other comparisons were also significant, favouring the fixed-dose combinations (all p<0·0001). All systolic blood pressure comparisons were also significant (all p<0·01). At least one treatment-emergent adverse event was experienced by 30-36% of participants in each group.

INTERPRETATION

Nebivolol and valsartan fixed-dose combination is an effective and well-tolerated treatment option for patients with hypertension.

FUNDING

Forest Research Institute.

Predicting in vivo cardiovascular properties of β-blockers from cellular assays: a quantitative comparison of cellular and cardiovascular pharmacological responses

β-Adrenoceptor antagonists differ in their degree of partial agonism. In vitro assays have provided information on ligand affinity, selectivity, and intrinsic efficacy. However, the extent to which these properties are manifest in vivo is less clear. Conscious freely moving rats, instrumented for measurement of heart rate (β1; HR) and hindquarters vascular conductance (β2; HVC) were used to measure receptor selectivity and ligand efficacy in vivo. CGP 20712A caused a dose-dependent decrease in basal HR (P<0.05, ANOVA) at 5 doses between 6.7 and 670 μg/kg (i.v.) and shifted the dose-response curve for isoprenaline to higher agonist concentrations without altering HVC responses. In contrast, at doses of 67 μg/kg (i.v.) and above, ICI 118551 substantially reduced the HVC response to isoprenaline without affecting HR responses. ZD 7114, xamoterol, and bucindolol significantly increased basal HR (ΔHR: +122 ± 12, + 129 ± 11, and + 59 ± 11 beats/min, respectively; n=6), whereas other β-blockers caused significant reductions (all at 2 mg/kg i.v.). The agonist effects of xamoterol and ZD 7114 were equivalent to that of the highest dose of isoprenaline. Bucindolol, however, significantly antagonized the response to the highest doses isoprenaline. An excellent correlation was obtained between in vivo and in vitro measures of β1-adrenoceptor efficacy (R(2)=0.93; P<0.0001).

Hypertension and its management in countries in Africa and the Middle East, with special reference to the place of β-blockade

BACKGROUND

The prevalence and clinical consequences of hypertension in countries in Africa and the Middle East have not been studied as well as in other regions.

SCOPE

We have reviewed the literature on the epidemiology and management of hypertension and related cardiovascular complications in countries within Africa and the Middle East. A PubMed search for countries in the region and 'hypertension' was supplemented by articles identified from reviews, and by literature suggested by the authors.

FINDINGS

The prevalence of hypertension is >20% in some countries in the Middle East and Africa, despite an average population age that is some 10-15 years lower than those of developed countries. Hypertension in these countries is associated with an increased risk of cardiovascular risk factors and cardiovascular disease, as elsewhere. Awareness rates of hypertension are low. Hypertension and its complications are undertreated, and mortality rates from cardiovascular disease are higher than in developed countries.

CONCLUSION

Available resources should be brought to bear on the management of hypertension in these countries. In particular, a recent downgrading of the importance of β-blockers in hypertension management guidelines needs to be reassessed. These agents are as effective as other antihypertensive classes both on blood pressures and on cardiovascular event rates. General concerns over an increased rate of new-onset diabetes with β-blockers have been overstated, although these agents should be avoided in metabolic syndrome.

The role of β-blockers in the management of hypertension: an Asian perspective

Following publication of the National Institute of Clinical Excellence (NICE) Guidelines in 2006, the use of β-blockers as first-line therapy in hypertension has been somewhat controversial. However, a recent reappraisal of the European Society of Hypertension guidelines highlights that these agents exhibit similar BP lowering efficacy to other classes of agents, prompting a re-examination of the utility of these agents in various patient populations. The authors felt that it is important to address this controversy and provide an Asian perspective on the place of β-blockers in current clinical practice and the benefits of β-blockade in selected patient populations. In addition to their use as a potential first-line therapy in uncomplicated hypertension, β-blockers have a particular role in patients with hypertension and comorbidities such as heart failure or coronary artery disease, including those who had a myocardial infarction. One advantage which β-blockers offer is the additional protective effects in patients with prior cardiovascular events. Some of the disadvantages attributed to β-blockers appear more related to the older drugs in this class and further appraisal of the efficacy and safety profile of newer β-blockers will lend support to the current guideline recommendations in Asian countries and encourage increased appropriate use of β-blockade in current clinical practice within Asia.

Clinical updates on carvedilol: a first choice beta-blocker in the treatment of cardiovascular diseases

IMPORTANCE OF THE FIELD

Carvedilol, a non-selective beta-blocker, has recently drawn attention because of its therapeutic benefits over other prescribed analogues for the treatment of cardiovascular diseases (CVDs).

AREAS COVERED IN THIS REVIEW

The present review attempts to present the clinical efficacy of carvedilol in comparison to other available beta-blockers. The literature search was carried out in three electronic databases (Unbound Medline, Pubmed and Sciencedirect) and internet search engines (Scirus and Google Scholar) without time constraints to ensure maximum literature coverage.

WHAT THE READER WILL GAIN

A relatively large number of comparative studies have revealed that carvedilol has advantage over traditional beta-blockers with respect to hemodynamic and metabolic effects, due to its unique non-selective alpha-/beta-adrenoceptor affinity. Such results indicate its safe and effective therapeutic application particularly in patients with complicated CVDs, even in pediatric and geriatric patients.

TAKE HOME MESSAGE

The therapeutic profile of carvedilol indicates its suitability for treatment of complicated CVDs than other non-selective beta-blockers. However, there is a limitation in terms of its dose due to its low bioavailability (approximately 25%). Therefore, there is still need for bioavailability enhancement and dose reduction to further improve the therapeutic efficacy of the drug.