[Beta-blockers : myths and facts]. / Bêtabloquants: entre mythes et réalité.

Beta-blockers are very commonly drugs used in clinical practice, but whose mechanisms and clinical impacts are not always well understood, especially in certain specific clinical situations. This article proposes a review of some pharmacology notions over the different generations of ß-blockers, as well as a review of indications and side effects in particular clinical situations, such as COPD, portal hypertension with esophageal varices and erectile dysfunction. Finally, an overview of response variability of these treatments is discussed from a genetic point of view.

Les bêtabloquants sont des traitements médicamenteux couramment utilisés en pratique clinique mais dont les mécanismes et les impacts demeurent parfois méconnus, notamment dans certaines situations cliniques spécifiques. Cet article propose une revue de quelques notions pharmacologiques des différentes générations de bêtabloquants, ainsi que les indications et effets secondaires dans des situations cliniques particulières, comme la BPCO, l'hypertension portale avec varices œsophagiennes et la dysfonction érectile. Enfin, un survol de la variabilité de réponses à ces traitements est abordé notamment d'un point de vue génétique.

Three Generations of ß-blockers: History, Class Differences and Clinical Applicability.

BACKGROUND: Beta-adrenergic receptors are expressed in cardiomyocytes and activated by either noradrenaline released from sympathetic synapses or circulating catecholamines. Their corresponding receptors have three subtypes, namely, ß1, ß2 and ß3, which are members of the G protein-coupled receptors (GPCRs) family. Activation of ß1-adrenergic receptors causes various physiological reactions including cardiac contraction and renin secretion from juxtaglomerular cells of the kidney. Antagonists of ß-adrenergic receptors, known as ß-blockers, have been used effectively for over four decades and have beneficial effects in the treatment of cardiovascular diseases. There are three generations of ß-blockers according to their pharmacological properties. Firstgeneration ß-blockers are non-selective, blocking both ß1- and ß2-receptors; second-generation ß- blockers are more cardioselective in that they are more selective for ß1-receptors; and thirdgeneration ß-blockers are highly selective drugs for ß1-receptors. The latter also display vasodilator actions by blocking α1-adrenoreceptors and activating ß3-adrenergic receptors. In addition, thirdgeneration ß-blockers exhibit angiogenic, antioxidant, anti-proliferative, anti-hypertrophic and antiapoptotic activities among other effects that are still under investigation. CONCLUSION: The objective of this review is to describe the evolution observed during the development of the three distinctive generations, thereby highlighting the advantages of third-generation ß- blockers over the other two drug classes.

[Ocular hypotensive effect of systemic beta-blockers in patients with primary glaucoma and arterial hypertension]. / Oftal'mogipotenzivnyĭ éffekt sistemnogo primeneniia beta-blokatorov pri pervichnoĭ glaukome i arterial'noĭ gipertenzii.

AIM: to evaluate the ocular hypotensive efficacy of systemic beta-blockers in primary glaucoma patients suffering from arterial hypertension (AH). MATERIAL AND METHODS: The study included 29 patients with POAG (58 eyes) aged from 47 to 83 years. Patients with stage I-III POAG received instillations of prostaglandin analogs and carbonic anhydrase inhibitors. All POAG patients also suffered from arterial hypertension and were prescribed selective beta-blockers (metoprolol, bisoprolol, or nebivalol) as monotherapy or as part of combination therapy (if the target arterial pressure had not been achieved under the initial treatment). After the start of oral beta-blockers therapy, the patients were re-examined at 2 and 4 weeks, 3 months, 6 months, and 1 year. RESULTS: A clinically significant reduction of IOP in the most seriously affected eye - by 3.3 mmHg (p<0.05), or 14% - occurred four weeks after the start of selective beta-blockers. Over three months of combination therapy, IOP in the 'worst' eye decreased by 4.4 mmHg (18.5%). At 1 year, IOP in the 'worst' eye was 6.2 mmHg (26%) lower than at baseline (p<0.05). CONCLUSION: Aged and senile patients with primary glaucoma usually suffer from polypathy (on average, they have 6.3±0.6 concurrent somatic diseases). To reduce the risk of polypharmacy and the frequency of side effects in the treatment of POAG and AH patients, it is advised that the treatment includes oral selective beta-blockers able to provide target levels of arterial pressure and IOP. In this study, oral beta-blockers in POAG and AH patients enabled IOP reduction as great as 18.5%-26% of baseline values over a 1-year follow-up period.

Achieving a Maximally Tolerated ß-Blocker Dose in Heart Failure Patients: Is There Room for Improvement?

Heart failure (HF) is associated with significant morbidity and mortality. Although initially thought to be harmful in HF, beta-adrenergic blockers (ß-blockers) have consistently been shown to reduce mortality and HF hospitalization in chronic HF with reduced ejection fraction. Proposed mechanisms include neurohormonal blockade and heart rate reduction. A new therapeutic agent now exists to target further heart rate lowering in patients who have been stable on a "maximally tolerated ß-blocker dose," but this definition and how to achieve it are incompletely understood. In this review, the authors summarize published reports on the mechanisms by which ß-blockers improve clinical outcomes. The authors describe differences in doses achieved in landmark clinical trials and those observed in routine clinical practice. They further discuss reasons for intolerance and the evidence behind using ß-blocker dose and heart rate as therapeutic targets. Finally, the authors offer recommendations for clinicians actively initiating and up-titrating ß-blockers that may aid in achieving maximally tolerated doses.

Medication adherence and persistence according to different antihypertensive drug classes: A retrospective cohort study of 255,500 patients.

BACKGROUND: Suboptimal adherence to antihypertensives leads to adverse clinical outcomes. This study aims to determine and compare medication adherence and persistence to different first-line antihypertensive drug classes in a large cohort. METHODS: A cohort study was performed using claims data for prescriptions in the German statutory health insurance scheme that insures approximately 90% of the population. A total of 255,500 patients with a first prescription of an antihypertensive were included and followed for 24months. Persistence was determined based on gaps in continuous dispensation. Adherence was analyzed by calculating the medication possession ratio (MPR). RESULTS: Within a 2-year period, 79.3% of all incident users of antihypertensive monotherapy met the classification of non-persistence (gap >0.5 times the number of days supplied with medication) and 56.3% of non-adherence (MPR<0.8). Beta-blockers (42.5%) and angiotensin-converting enzyme inhibitors (31.9%) were the most widely prescribed drug classes. Non-persistence and non-adherence were highest for diuretics (85.4%, n=6149 and 66.3%, n=4774) and lowest for beta-blockers (77.6%, n=76,729 and 55.2%, n=54,559). The first gap of antihypertensive medication occurred in median 160-250days after initiation, and the average medication possession ratio for all drug classes was less than 0.8. Fixed combinations with diuretics showed a 19.8% lower chance for non-adherence (OR=0.802, 99.9% CI=[0.715-0.900], p<0.001) and an 8.4% lower hazard for non-persistence (HR 0.916, 99.9% CI=[0.863-0.973], p<0.001) compared with monotherapies. CONCLUSIONS: This large cohort study reveals important differences in 2-year adherence and persistence between antihypertensives that were lowest for diuretics. Fixed-dose combinations with diuretics may facilitate adherence compared to single substance products. However, effective strategies to improve adherence to antihypertensives are needed regardless of drug class.

Relationship between different doses of beta-blockers and prognosis in elderly patients with reduced ejection fraction.

BACKGROUND: Beta-blockers (BBs) remain underused in elderly patients with reduced ejection fraction (REF). Our aim was to determine the prognostic impact of different doses of BB in this setting. METHODS AND RESULTS: A single-center observational study was conducted. Inclusion criteria were age≥75 and EF≤0.35. Six months after diagnosis, patients were divided into 3 groups depending on BB dose: no BB (NBB), low dose (<50% of the target dose) (LD), and high dose (≥50%) (HD). Two different analytical approaches were employed: multivariate Cox model and propensity-score (PS) matching. Outcomes were all-cause death and heart failure (HF) admission. We included 559 patients (134 NBB, 259 LD, and 166 HD) with median follow-up of 29.9months. There were 212 deaths (NBB: 70 (52.2%); LD: 94 (36.3%); and HD: 48 (28.9%)) and 171 HF admissions (NBB: 42 (31.3%); LD: 85 (32.8%); and HD: 44 (26.5%)). On multivariate analysis, both LD and HD were associated with improved survival, with no differences between them (HD vs. NBB=0.67, 95% CI=[0.46-0.98], p=0.037; HD vs. LD=1.03, 95% CI=[0.72-1.46], p=0.894; and LD vs. NBB=0.65, 95% CI=[0.48-0.90], p=0.009). However, BB therapy failed to show benefits in HF admissions (p=NS, for each comparison). PS-matched analysis included 198 patients, with similar results to those mentioned above. CONCLUSIONS: BB therapy was associated with a significant reduction in mortality among elderly patients with REF, regardless of dose. Nevertheless, it was not associated with a decrease in HF admissions. Further studies are needed to determine the optimal BB dose in these patients.

Propafenone shows class Ic and class II antiarrhythmic effects.

AIMS: Propafenone is a well-known Class Ic antiarrhythmic agent. It has the typical chemical structure of a beta-blocker, but human studies on its beta-blocking effects revealed conflicting results. METHODS AND RESULTS: Twelve healthy males received single oral doses of 600 mg propafenone and placebo according to a randomized, double-blind, placebo-controlled, cross-over protocol. Four hours following drug intake, heart rate and blood pressure were measured, and plasma concentrations of propafenone were determined at rest, during exercise and after recovery. At exercise, propafenone significantly decreased heart rate (-6%, P < 0.05), systolic blood pressure (-6%, P < 0.05), and the rate-pressure product (-11%, P < 0.05). Plasma concentrations of propafenone increased during exercise (+23%, P < 0.05) and decreased during recovery (-33%, P < 0.05). CONCLUSION: Both effects on heart rate and blood pressure as well as the changes of plasma concentrations of propafenone during exercise represent two particular features of beta-blockers. Therefore, we conclude that propafenone is both a Class Ic and a Class II antiarrhythmic agent, and 600 mg propafenone, i.e. the dose recommended in current guidelines for cardioversion of paroxysmal atrial fibrillation, cause clinically significant beta-blockade. Thus, single oral doses of 600 mg propafenone appear also suitable for cardioversion of paroxysmal atrial fibrillation in patients with structural heart disease since beta-blockers are explicitly indicated in the treatment of both coronary artery disease and heart failure.

Economic benefits associated with beta blocker persistence in the treatment of hypertension: a retrospective database analysis.

OBJECTIVES: To assess the association between medical costs and persistence with beta blockers among hypertensive patients, and to quantify persistence related medical cost differences with nebivolol, which is associated with improved tolerability, versus other beta blockers. METHODS: Adults who initiated hypertension treatment with a beta blocker were identified from the MarketScan * claims database (2008-2012). Patients were classified based on their first beta blocker use: nebivolol, atenolol, carvedilol, metoprolol, and other beta blockers. Patients with compelling indications for atenolol, carvedilol or metoprolol (acute coronary syndrome and congestive heart failure) were excluded. Patients enrolled in health maintenance organization or capitated point of service insurance plans were also excluded. Persistence was defined as continuous use of the index drug (<60 day gap). The average effect of persistence on medical costs (2012 USD) was estimated using generalized linear models (GLMs). Regression estimates were used to predict medical cost differences associated with persistence between nebivolol and the other cohorts. RESULTS: A total of 587,424 hypertensive patients met the inclusion criteria. Each additional month of persistence with any one beta blocker was associated with $152.51 in all-cause medical cost savings; continuous treatment for 1 year was associated with $1585.98 in all-cause medical cost savings. Patients treated with nebivolol had longer persistence during the 1 year study period (median: 315 days) than all other beta blockers (median: 156-292 days). Longer persistence with nebivolol translated into $305.74 all-cause medical cost savings relative to all other beta blockers. LIMITATIONS: The results may not be generalizable to hypertensive patients with acute coronary syndrome or congestive heart failure. CONCLUSIONS: Longer persistence with beta blockers for the treatment of hypertension was associated with lower medical costs. There may be greater cost savings due to better persistence with nebivolol than other beta blockers.

[Beta-blockers in septic shock: a review]. / Bloqueadores beta en shock séptico: una revisión.

In septic shock, high adrenergic stress is associated with cardiovascular and systemic adverse effects, which can negatively affect the results. Beta-adrenergic receptor block has been shown to be effective in controlling the disproportionate increase in heart rate, maintaining a favorable hemodynamic profile and apparently improving the efficiency of the cardiovascular system in order to maintain tissue perfusion. They have also been shown to modulate favorably catecholamine-induced immunosuppression and to decrease insulin resistance, protein catabolism, and proinflammatory cytokine expression associated with cardiovascular dysfunction. Selective beta-1 blockers appear to provide better results than non-selective blockers, even suggesting a positive impact on mortality. Future clinical trials are still needed to confirm these findings and define the scope of their benefits.

Intraclass differences among antihypertensive drugs.

The four major classes of antihypertensive drugs­diuretics, ß-blockers, calcium channel blockers, and renin-angiotensin system inhibitors (including angiotensin-converting enzyme inhibitors and angiotensin receptor blockers)­have significant qualitative and quantitative differences in the adverse effects they cause. Structural and chemical differences have been identified within these classes, especially among the calcium channel blockers and, to a lesser extent, among the thiazide/thiazide-like diuretics. However, it has been more difficult to demonstrate that these differences translate into differential effects with respect to either the surrogate endpoint of blood pressure reduction or, more importantly, hypertension-related cardiovascular complications. Based on a hierarchy-of-evidence approach, differences are apparent between hydrochlorothiazide and chlorthalidone based on evidence of moderate quality. Low-quality evidence suggests atenolol is less effective than other ß-blockers. However, no significant intraclass differences have been established among the other classes of antihypertensive drugs.

Beta-blockers and depression in elderly hypertension patients in primary care.

BACKGROUND AND OBJECTIVES: Previous findings regarding a possible association between beta-blocker use and depression are mixed. To our knowledge there have been no studies investigating the association of beta-blockers with depression in primary care hypertension patients without previous myocardial infarction. The aim of this study was to determine the relation between lipophilic beta-blocker use and depression in elderly primary care patients with hypertension. METHODS: This was a cross-sectional study in primary care practices located in the South of The Netherlands. Primary care hypertension patients without previous myocardial infarction or heart failure (n=573), aged between 60 and 85 years (mean age=70±6.6), were included. All patients underwent a structured interview that included a self-report questionnaire to assess depression (PHQ-9), which was divided in four groups (PHQ-9 score of 0, 1--3, 4--8, 9 or higher). RESULTS: A PHQ-9 score of 0 was more prevalent in non-beta-blocker users versus lipophilic beta-blocker users (46% versus 35%), a PHQ-9 score of 4--8 was less prevalent in non-beta-blocker users as compared with lipophilic beta-blocker users (14% versus 25%). A chi-squared test showed that lipophilic beta-blocker users as compared to non-beta-blockers users were more likely to be in a higher depression category. Ordinal regression showed a significant relationship between use of lipophilic beta-blockers and depression (OR=1.60, 95% CI=1.08--2.36) when adjusting for potential confounders. CONCLUSIONS: Our findings show that primary care hypertension patients who use a lipophilic beta-blocker are more likely to have higher depression scores than those who do not use a lipophilic beta-blocker.

Beta-blockers in older patients with heart failure and preserved ejection fraction: class, dosage, and outcomes.

BACKGROUND: We examined the clinical effectiveness of beta-blockers considered evidenced-based to heart failure and reduced ejection fraction (HFrEF) and their recommended target doses in older adults with HF and preserved ejection fraction (HFpEF). METHODS: In OPTIMIZE-HF (2003-2004) linked to Medicare (2003-2008), of the 10,570 older (age ≥ 65 years, mean, 81 years) adults with HFpEF (EF ≥ 40%, mean 55%), 8373 had no contraindications to beta-blocker therapy. After excluding 4614 patients receiving pre-admission beta-blockers, the remaining 3759 patients were potentially eligible for new discharge prescriptions for beta-blockers and 1454 received them. We assembled a propensity-matched cohort of 1099 pairs of patients receiving beta-blockers and no beta-blockers, balanced on 115 baseline characteristics. Evidence-based beta-blockers for HFrEF, namely, carvedilol, metoprolol succinate, and bisoprolol and their respective guideline-recommended target doses were 50, 200, and 10mg/day. RESULTS: During 6 years of follow-up, new discharge prescriptions for beta-blockers had no association with the primary composite endpoint of all-cause mortality or HF rehospitalization (hazard ratio, 1.03; 95% confidence interval {CI}, 0.94-1.13; p=0.569). This association did not vary by beta-blocker evidence class or daily dose. Hazard ratios for all-cause mortality and HF rehospitalization were 0.99 (95% CI, 0.90-1.10; p=0.897) and 1.17 (95% CI, 1.03-1.34; p=0.014), respectively. The latter association lost significance when higher EF cutoffs of ≥45%, ≥50% and ≥55% were used. CONCLUSIONS: Initiation of therapy with beta-blockers considered evidence-based for HFrEF and in target doses recommended for HFrEF had no association with the composite or individual endpoints of all-cause mortality or HF rehospitalization in HFpEF.

Ligand bias prevents class equality among beta-blockers.

ß-Blockers are used for a wide range of diseases from hypertension to glaucoma. In some diseases/conditions all ß-blockers are effective, while in others only certain subgroups are therapeutically beneficial. The best-documented example for only a subset of ß-blockers showing clinical efficacy is in heart failure, where members of the class have ranged from completely ineffective, to drugs of choice for treating the disease. Similarly, ß-blockers were tested in murine asthma models and two pilot clinical studies. A different subset was found to be effective for this clinical indication. These findings call into question the current system of classifying these drugs. To consider 'ß-blockers', as a single class is misleading when considering their rigorous pharmacological definition and their appropriate clinical application.

Pilot study of the effect of lipophilic vs. hydrophilic beta-adrenergic blockers being taken at time of intracardiac defibrillator discharge on subsequent PTSD symptoms.

A pathophysiological model of posttraumatic stress disorder (PTSD) posits that an overly strong stress response at the time of the traumatic event leads to overconsolidation of the event's memory in part through a central ß-adrenergic mechanism. We hypothesized that the presence of a ß-blocker in the patient's brain at the time of the traumatic event would reduce the PTSD outcome by blocking this effect. The unpredictable, uncontrollable discharge of an implantable intracardiac defibrillator (ICD) is experienced by most patients as highly stressful, and it has previously been shown to be capable of causing PTSD symptoms. The present pilot study evaluated a convenience sample of 18 male cardiac patients who had been taking either a lipophilic ß-blocker (which penetrates the blood-brain barrier) or a hydrophilic ß-blocker (which does not) at the time of a discharge of their ICD. The self- report PTSD Checklist-Specific Version quantified 17 PTSD symptoms pertaining to the ICD discharge during the month preceding the evaluation. There was a statistical trend for patients who had been taking a lipophilic ß-blocker at the time of the ICD discharge to have (35%) less severe PTSD symptoms than patients who had been taking a hydrophilic ß-blocker (one-tailed p=0.07, g=0.64). Further, prospective, randomized, controlled studies are suggested.

ß-Blocker use and all-cause mortality of melanoma patients: results from a population-based Dutch cohort study.

BACKGROUND: Results from preclinical and observational studies suggest that ß-adrenoreceptor inhibition might influence disease progression of melanoma. PATIENTS AND METHODS: Patients ⩾18years with cutaneous melanoma (Breslow thickness >1mm) registered in the Eindhoven Cancer Registry between January 1, 1998 and December 31, 2010, who were also registered with PHARMO record linkage system (RLS), were eligible. Randomly selected patients using ß-blockers from PHARMO record linkage system (RLS) matched on age and gender served as a control cohort. Adjusted time-dependent and time-fixed Cox proportional hazard models were employed to estimate the hazard ratio of all-cause mortality. Five-year relative survival rates for all-cause mortality were calculated to estimate disease specific survival. RESULTS: 203 of 709 eligible patients used ß-blockers after melanoma diagnosis. The use of ß-blockers was not associated with the risk of dying (adjusted hazard ratio (HR) 0.82, 95% confidence interval (CI) 0.55-1.24). Neither duration of exposure nor ß-blocker dosage showed significant influence on survival. Five-year relative survival for ß-blocker users was lower than in non-users amongst melanoma patients (80.9% and 83.7%, respectively) but higher among the ß-blocker control group compared to the general population (101.4%). CONCLUSION: Our results do not show a statistically significant impact of ß-blocker exposure on overall survival of melanoma patients, regardless of the timing, duration or dosage of ß-blocker use.