Serious Bleeding in Patients With Atrial Fibrillation Using Diltiazem With Apixaban or Rivaroxaban

Importance

Diltiazem, a commonly prescribed ventricular rate-control medication for patients with atrial fibrillation, inhibits apixaban and rivaroxaban elimination, possibly causing overanticoagulation.

Objective

To compare serious bleeding risk for new users of apixaban or rivaroxaban with atrial fibrillation treated with diltiazem or metoprolol.

Design, Setting, and Participants

This retrospective cohort study included Medicare beneficiaries aged 65 years or older with atrial fibrillation who initiated apixaban or rivaroxaban use and also began treatment with diltiazem or metoprolol between January 1, 2012, and November 29, 2020. Patients were followed up to 365 days through November 30, 2020. Data were analyzed from August 2023 to February 2024.

Exposures

Diltiazem and metoprolol.

Main Outcomes and Measures

The primary outcome was a composite of bleeding-related hospitalization and death with recent evidence of bleeding. Secondary outcomes were ischemic stroke or systemic embolism, major ischemic or hemorrhagic events (ischemic stroke, systemic embolism, intracranial or fatal extracranial bleeding, or death with recent evidence of bleeding), and death without recent evidence of bleeding. Hazard ratios (HRs) and rate differences (RDs) were adjusted for covariate differences with overlap weighting.

Results

The study included 204 155 US Medicare beneficiaries, of whom 53 275 received diltiazem and 150 880 received metoprolol. Study patients (mean [SD] age, 76.9 [7.0] years; 52.7% female) had 90 927 person-years (PY) of follow-up (median, 120 [IQR, 59-281] days). Patients receiving diltiazem treatment had increased risk for the primary outcome (RD, 10.6 [95% CI, 7.0-14.2] per 1000 PY; HR, 1.21 [95% CI, 1.13-1.29]) and its components of bleeding-related hospitalization (RD, 8.2 [95% CI, 5.1-11.4] per 1000 PY; HR, 1.22 [95% CI, 1.13-1.31]) and death with recent evidence of bleeding (RD, 2.4 [95% CI, 0.6-4.2] per 1000 PY; HR, 1.19 [95% CI, 1.05-1.34]) compared with patients receiving metoprolol. Risk for the primary outcome with initial diltiazem doses exceeding 120 mg/d (RD, 15.1 [95% CI, 10.2-20.1] per 1000 PY; HR, 1.29 [95% CI, 1.19-1.39]) was greater than that for lower doses (RD, 6.7 [95% CI, 2.0-11.4] per 1000 PY; HR, 1.13 [95% CI, 1.04-1.24]). For doses exceeding 120 mg/d, the risk of major ischemic or hemorrhagic events was increased (HR, 1.14 [95% CI, 1.02-1.27]). Neither dose group had significant changes in the risk for ischemic stroke or systemic embolism or death without recent evidence of bleeding. When patients receiving high- and low-dose diltiazem treatment were directly compared, the HR for the primary outcome was 1.14 (95% CI, 1.02-1.26).

Conclusions and Relevance

In Medicare patients with atrial fibrillation receiving apixaban or rivaroxaban, diltiazem was associated with greater risk of serious bleeding than metoprolol, particularly for diltiazem doses exceeding 120 mg/d.

Beta-Blockers after Myocardial Infarction and Preserved Ejection Fraction

BACKGROUND

Most trials that have shown a benefit of beta-blocker treatment after myocardial infarction included patients with large myocardial infarctions and were conducted in an era before modern biomarker-based diagnosis of myocardial infarction and treatment with percutaneous coronary intervention, antithrombotic agents, high-intensity statins, and renin-angiotensin-aldosterone system antagonists.

METHODS

In a parallel-group, open-label trial performed at 45 centers in Sweden, Estonia, and New Zealand, we randomly assigned patients with an acute myocardial infarction who had undergone coronary angiography and had a left ventricular ejection fraction of at least 50% to receive either long-term treatment with a beta-blocker (metoprolol or bisoprolol) or no beta-blocker treatment. The primary end point was a composite of death from any cause or new myocardial infarction.

RESULTS

From September 2017 through May 2023, a total of 5020 patients were enrolled (95.4% of whom were from Sweden). The median follow-up was 3.5 years (interquartile range, 2.2 to 4.7). A primary end-point event occurred in 199 of 2508 patients (7.9%) in the beta-blocker group and in 208 of 2512 patients (8.3%) in the no-beta-blocker group (hazard ratio, 0.96; 95% confidence interval, 0.79 to 1.16; P = 0.64). Beta-blocker treatment did not appear to lead to a lower cumulative incidence of the secondary end points (death from any cause, 3.9% in the beta-blocker group and 4.1% in the no-beta-blocker group; death from cardiovascular causes, 1.5% and 1.3%, respectively; myocardial infarction, 4.5% and 4.7%; hospitalization for atrial fibrillation, 1.1% and 1.4%; and hospitalization for heart failure, 0.8% and 0.9%). With regard to safety end points, hospitalization for bradycardia, second- or third-degree atrioventricular block, hypotension, syncope, or implantation of a pacemaker occurred in 3.4% of the patients in the beta-blocker group and in 3.2% of those in the no-beta-blocker group; hospitalization for asthma or chronic obstructive pulmonary disease in 0.6% and 0.6%, respectively; and hospitalization for stroke in 1.4% and 1.8%.

CONCLUSIONS

Among patients with acute myocardial infarction who underwent early coronary angiography and had a preserved left ventricular ejection fraction (≥50%), long-term beta-blocker treatment did not lead to a lower risk of the composite primary end point of death from any cause or new myocardial infarction than no beta-blocker use. (Funded by the Swedish Research Council and others; REDUCE-AMI ClinicalTrials.gov number, NCT03278509.).

Pharmacokinetics and bioequivalence of two metoprolol succinate extended release tablets in healthy Chinese subjects under fasting and fed conditions

AIMS

The aims of this study were to evaluate and compare the pharmacokinetic profiles and establish bioequivalence of test and reference metoprolol succinate extended-release (ER) tablets in healthy Chinese subjects under fasting and fed conditions.

MATERIALS AND METHODS

Subjects were randomly assigned to either the fasting or the fed group and also to one of the two treatment sequences (test-reference or reference-test), according to which they received a single 47.5-mg dose of the test or reference metoprolol ER tablet in the study periods. During each period, blood samples were collected at pre-dose and at intervals up to 48 hours after dosing. Plasma concentrations of metoprolol were determined by liquid chromatography. The safety of both ER tablets was monitored throughout the study.

RESULTS

60 subjects were enrolled and all completed the study, with 30 participants each in the fasting and fed groups. In both groups, the 90% confidence intervals for AUC0-48h, AUC0-inf, and Cmax were within the acceptable bioequivalence range (80 - 125%). There were no significant differences in adverse event (AE) reporting between the subjects receiving test or reference ER tablet. No serious AEs occurred during the study period.

CONCLUSION

The test metoprolol ER tablet was bioequivalent to the reference metoprolol ER tablet (Betaloc ZOK) in healthy Chinese subjects measured under both fasting and fed conditions. Both formulations were well tolerated by all study participants.

The role of plasma concentrations and drug characteristics of beta-blockers in fall risk of older persons

Beta-blocker usage is inconsistently associated with increased fall risk in the literature. However, due to age-related changes and interindividual heterogeneity in pharmacokinetics and dynamics, it is difficult to predict which older adults are more at risk for falls. Therefore, we wanted to explore whether elevated plasma concentrations of selective and nonselective beta-blockers are associated with an increased risk of falls in older beta-blocker users. To answer our research question, we analyzed samples of selective (metoprolol, n = 316) and nonselective beta-blockers (sotalol, timolol, propranolol, and carvedilol, n = 179) users from the B-PROOF cohort. The associations between the beta-blocker concentration and time to first fall were assessed using Cox proportional hazard models. Change of concentration over time in relation to fall risk was assessed with logistic regression models. Models were adjusted for potential confounders. Our results showed that above the median concentration of metoprolol was associated with an increased fall risk (HR 1.55 [1.11-2.16], p = .01). No association was found for nonselective beta-blocker concentrations. Also, changes in concentration over time were not associated with increased fall risk. To conclude, metoprolol plasma concentrations were associated with an increased risk of falls in metoprolol users while no associations were found for nonselective beta-blockers users. This might be caused by a decreased β1-selectivity in high plasma concentrations. In the future, beta-blocker concentrations could potentially help clinicians estimate fall risk in older beta-blockers users and personalize treatment.

Association between P-pulmonale and respiratory morbidity in COPD: a secondary analysis of the BLOCK-COPD trial

RATIONALE

Pulmonary hypertension (PH) in COPD confers increased risk of exacerbations (ECOPD). Electrocardiogram (ECG) indicators of PH are prognostic both in PH and COPD. In the Beta-Blockers for the Prevention of Acute Exacerbations of COPD (BLOCK-COPD) trial, metoprolol increased risk of severe ECOPD through unclear mechanisms.

OBJECTIVE

We evaluated whether an ECG indicator of PH, P-pulmonale, would be associated with ECOPD and whether participants with P-pulmonale randomized to metoprolol were at higher risk of ECOPD and worsened respiratory symptoms given the potential detrimental effects of beta-blockers in PH.

METHODS

ECGs of 501 participants were analyzed for P-pulmonale (P wave enlargement in lead II). Cox proportional hazards models evaluated for associations between P-pulmonale and time to ECOPD (all and severe) for all participants and by treatment assignment (metoprolol vs. placebo). Linear mixed-effects models evaluated the association between treatment assignment and P-pulmonale on change in symptom scores (measured by CAT and SOBQ).

RESULTS

We identified no association between P-pulmonale and risk of any ECOPD or severe ECOPD. However, in individuals with P-pulmonale, metoprolol was associated with increased risk for ECOPD (aHR 2.92, 95% CI: 1.45-5.85). There was no association between metoprolol and ECOPD in individuals without P-pulmonale (aHR 1.01, 95% CI: 0.77-1.31). Individuals with P-pulmonale assigned to metoprolol experienced worsening symptoms (mean increase of 3.95, 95% CI: 1.32-6.58) whereas those assigned to placebo experienced a mean improvement in CAT score of -2.45 (95% CI: -0.30- -4.61).

CONCLUSIONS

In individuals with P-pulmonale, metoprolol was associated with increased exacerbation risk and worsened symptoms. These findings may explain the findings observed in BLOCK-COPD.

Improvement in hemodynamics of amlodipine besylate combined with metoprolol in patients with hypertension complicated by heart failure

To observe the effect of amlodipine besylate combined with metoprolol in treating hypertension and heart failure. Total number of patients with hypertension combined with HF admitted to our hospital was One hundred and fifty from May 2017 to May 2022 selected for the study and they were distributed into single drug group and combination group by the method of random number table, with the total number of 75 cases in every group. Metoprolol treatment was given to the single drug group and metoprolol combined with amlodipine besylate treatment was given to the combination group. Both groups' scientific outcomes were compared, including their ventricular function, inflammatory factors, hemodynamics and liver and kidney function. Adverse treatment-related side events for patients were also tallied. Compared to the single drug group, the combination group's overall treatment effectiveness was higher (P<0.05). The combined group had better ventricular function, improved hemodynamics and lower levels of inflammatory factors (P<0.05). The liver, kidney function and adverse effects outcomes were the same in both groups (P>0.05). Amlodipine besylate combined with metoprolol has a better clinical effect in treating hypertension combined with heart failure, which can more effectively improve patients' cardiac function, inflammation and hemodynamics.

Comparison of new-onset post-operative atrial fibrillation between patients receiving carvedilol and metoprolol after off-pump coronary artery bypass graft surgery

OBJECTIVE

Post-operative atrial fibrillation (POAF) is a common complication of coronary artery bypass graft (CABG) surgery. Previous studies suggest carvedilol is more effective than metoprolol in preventing POAF in on-pump CABG. This study investigated if the same benefit would be seen in off-pump CABG.

METHODS

This single-center, retrospective review compared rates of new-onset POAF between adult patients who received carvedilol and metoprolol after off-pump CABG surgery. Safety endpoints included hypotension, bradycardia, dyspnea, and the composite. Multivariate logistic regression was conducted to identify associations between demographics, potential confounders, and beta-blocker dose and POAF. Kaplan-Meier plots and Cox proportional-hazards models examined differences in time-to-event for POAF.

RESULTS

134 patients were included (34 carvedilol and 100 metoprolol). The mean age was 63 years, 70.9% were male, 85% had history of hypertension, 3.7% had history of heart failure with reduced ejection fraction, and 38.8% were taking beta blockers prior to admission. POAF developed in 2 patients (5.8%) in the carvedilol group and 24 patients (24.0%) in the metoprolol group (odds ratio 0.17 [95% CI 0.03-0.83], p = 0.023). Safety endpoints occurred in 10 carvedilol (29.4%) and 44 metoprolol (44.0%) patients (p = 0.134). Hypotension and dyspnea rates were similar between groups; bradycardia occurred more commonly among metoprolol-treated patients (p = 0.040). Time-to-event analyses revealed a hazard ratio = 0.22 (95% CI 0.05-0.93, p = 0.040) for carvedilol use.

CONCLUSIONS

In this single-center, retrospective study of off-pump CABG patients, carvedilol was associated with reduced POAF risk and enhanced safety compared to metoprolol.

Co-prescription of metoprolol and CYP2D6-inhibiting antidepressants before and after implementation of an optimized drug interaction database in Norway

Purpose

To compare the co-prescription of metoprolol and potent CYP2D6-inhibiting antidepressants before and during a 10-year period after implementation of an optimized drug interaction database into clinical decision support systems in Norway.

Methods

The study was a retrospective, cross-sequential nationwide analysis of drug-dispensing data retrieved from the Norwegian Prescription Database over a 1-year period before (2007) and two 1-year periods after (2012 and 2017) implementation of a drug interaction database providing recommendations on non-interacting alternative medications. Primary outcome was changes in co-prescription rates of metoprolol and the potent CYP2D6-inhibiting antidepressants fluoxetine, paroxetine, or bupropion relative to alternative antidepressants with no or limited CYP2D6 inhibitory potential. To control for potential secular trend bias, a comparison group consisting of atenolol/bisoprolol users was included.

Results

The co-prescription rate of metoprolol with potent CYP2D6 inhibitors declined following implementation of the optimized database, by 21% (P < 0.001) after 5 years and by 40% (P < 0.001) after 10 years. Compared with atenolol/bisoprolol users, patients treated with metoprolol had significantly reduced likelihood of being prescribed a CYP2D6-inhibiting antidepressant in the two post-implementation periods (OR 0.61 (95% CI 0.54–0.69) and OR 0.45 (95% CI 0.40–0.51), respectively, versus OR 0.84 (95% CI 0.74–0.94) prior to implementation). Small and mostly insignificant differences in average daily metoprolol dosage were found between patients treated with the various antidepressants.

Conclusion

The present study suggests that implementation of a drug interaction database providing recommendations on non-interacting drug alternatives contributes to reduced co-prescribing of drug combinations associated with potentially serious adverse effects.

Intravenous Metoprolol Versus Diltiazem for Rate Control in Atrial Fibrillation

BACKGROUND

Currently, it remains unclear whether β-blockers or nondihydropyridine calcium channel blockers are preferred for the acute management of atrial fibrillation (AF).

OBJECTIVE

The objective of this study was to compare the efficacy and safety of intravenous (IV) metoprolol and diltiazem for rate control.

METHODS

This was a single-center, retrospective cohort study of patients who presented to the emergency department between 2015 and 2019 with AF with rapid ventricular rate (RVR) and received IV metoprolol or diltiazem. The primary outcome was the percentage of patients who achieved rate control (defined as heart rate < 100 beats per minute). Secondary outcomes included time to rate control, percentage of patients requiring additional agents for rate control, and incidence of cardioversion, bradycardia, and hypotension.

RESULTS

A total of 200 patients were included in this study. Rate control was achieved in 35% and 41% of the metoprolol and diltiazem groups, respectively (P = 0.38). Mean time to rate control was not significantly different between the metoprolol and diltiazem groups (35 vs 21 minutes, P = 0.23). One patient developed hypotension, no patient developed bradycardia, and 4 patients required electric cardioversion. No adverse events were observed in patients with ejection fraction ≤40%.

CONCLUSION AND RELEVANCE

There was no difference in the achievement of rate control between IV metoprolol and diltiazem. This is the largest study to date comparing the two classes of agents for acute rate control in AF. No patient-specific factors were identified that would influence the preferential use of one medication over the other.

Effect of metoprolol tartrate tablets and recombinant human B-type natriuretic peptide on the sudden cardiac death and malignant arrhythmias in patients with acute myocardial infarction and heart failure

To explore the effect of metoprolol tartrate tablets and recombinant human natriuretic peptide B (NPPB) on sudden cardiac death and malignant arrhythmias in patients with acute myocardial infarction and patients with heart failure (AMI-HF). A total of 105 AMI-HF patients treatedfrom January 2020 and June 2021 were enrolled and divided into Group I (n=53) and Group II (n=52). Both groups received conventional treatment, and Group II was additionally treated with metoprolol tartrate tablets and NPPB. The clinical observation indicators of the two groups of patients were compared. Group II had better left ventricular end diastolic diameter (LVEDd), left ventricular end systolic diameter (LVESD) and left ventricular ejection fraction (LVEF) (p<0.05). The standard deviation of NN (R-R) interval (SDNN), mean NN (R-R), root mean square of continuous difference (RMSSD) and the percentage of difference between adjacent RR intervals >50ms (pNN50) increased after treatment, with more increase in the Group II (p<0.05). Group II obtained significantly lower levels of B type natriuretic peptide (BNP),N terminal pro B type natriuretic peptide (NT-ProBNP), interleukin (IL)-6 and hs-CRP in contrast to Group I (p<0.05). Markedly higher total response rates were observed in Group II (p<0.05). The combination of metoprolol tartrate tablets and NPPB is effective in treating AMI-HF.

Oral Manifestations of Commonly Prescribed Drugs

Drugs are being prescribed with more frequency and in higher quantities. A serious adverse drug event from prescribed medications constitutes 2.4% to 16.2% of all hospital admissions. Many of the adverse drug events present intraorally or periorally in isolation or as a clinical symptom of a systemic effect. Clinical recognition and treatment of adverse drug events are important to increase patient adherence, manage drug therapy, or detect early signs of potentially serious outcomes. Oral manifestations of commonly prescribed medications include gingival enlargement, oral hyperpigmentation, oral hypersensitivity reaction, medication-related osteonecrosis, xerostomia, and other oral or perioral conditions. To prevent dose-dependent adverse drug reactions, physicians should prescribe medications judiciously using the lowest effective dose with minimal duration. Alternatively, for oral hypersensitivity reactions that are not dose dependent, quick recognition of clinical symptoms associated with time-dependent drug onset can allow for immediate discontinuation of the medication without discontinuation of other medications. Physicians can manage oral adverse drug events in the office through oral hygiene instructions for gingival enlargement, medication discontinuation for oral pigmentation, and prescription of higher fluoride toothpastes for xerostomia.

Left ventricular functional recovery of infarcted and remote myocardium after ST-segment elevation myocardial infarction (METOCARD-CNIC randomized clinical trial substudy)

BACKGROUND

We aimed to evaluate the effect of early intravenous metoprolol treatment, microvascular obstruction (MVO), intramyocardial hemorrhage (IMH) and adverse left ventricular (LV) remodeling on the evolution of infarct and remote zone circumferential strain after acute anterior ST-segment elevation myocardial infarction (STEMI) with feature-tracking cardiovascular magnetic resonance (CMR).

METHODS

A total of 191 patients with acute anterior STEMI enrolled in the METOCARD-CNIC randomized clinical trial were evaluated. LV infarct zone and remote zone circumferential strain were measured with feature-tracking CMR at 1 week and 6 months after STEMI.

RESULTS

In the overall population, the infarct zone circumferential strain significantly improved from 1 week to 6 months after STEMI (- 8.6 ± 9.0% to - 14.5 ± 8.0%; P < 0.001), while no changes in the remote zone strain were observed (- 19.5 ± 5.9% to - 19.2 ± 3.9%; P = 0.466). Patients who received early intravenous metoprolol had significantly more preserved infarct zone circumferential strain compared to the controls at 1 week (P = 0.038) and at 6 months (P = 0.033) after STEMI, while no differences in remote zone strain were observed. The infarct zone circumferential strain was significantly impaired in patients with MVO and IMH compared to those without (P < 0.001 at 1 week and 6 months), however it improved between both time points regardless of the presence of MVO or IMH (P < 0.001). In patients who developed adverse LV remodeling (defined as ≥ 20% increase in LV end-diastolic volume) remote zone circumferential strain worsened between 1 week and 6 months after STEMI (P = 0.036), while in the absence of adverse LV remodeling no significant changes in remote zone strain were observed.

CONCLUSIONS

Regional LV circumferential strain with feature-tracking CMR allowed comprehensive evaluation of the sequelae of an acute STEMI treated with primary percutaneous coronary intervention and demonstrated long-lasting cardioprotective effects of early intravenous metoprolol.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT01311700. Registered 8 March 2011 - Retrospectively registered.

Effect of eliglustat on the pharmacokinetics of digoxin, metoprolol, and oral contraceptives and absorption of eliglustat when coadministered with acid-reducing agents

Eliglustat is an oral substrate reduction therapy indicated for patients with Gaucher disease type 1. Based on in vitro data, clinical trials were conducted to assess the potential for drug-drug interactions between eliglustat and digoxin (P-glycoprotein substrate), metoprolol (sensitive CYP2D6 substrate), a combined oral contraceptive (CYP3A substrate), and acid-reducing agents. Healthy subjects were enrolled in four Phase 1 clinical studies to evaluate the effect of eliglustat on the pharmacokinetics, safety, and tolerability of digoxin (N = 28), metoprolol (N = 14), and a combined oral contraceptive (N = 30) and the effect of acid-reducing agents on eliglustat pharmacokinetics, safety, and tolerability (N = 24). Coadministration resulted in increased exposure to digoxin (1.49-fold) and metoprolol (2-fold) with eliglustat, negligible effects on oral contraceptive pharmacokinetics with eliglustat, and a negligible effect of acid-reducing agents on eliglustat pharmacokinetics. Across all studies, eliglustat was well-tolerated. One serious adverse event (spontaneous abortion) and one discontinuation due to an adverse event (urinary tract infection) were reported, both during the acid-reducing agents study. When eliglustat is coadministered with medications that are P-glycoprotein or CYP2D6 substrates, lower doses of these concomitant medications may be required. Eliglustat may be coadministered with oral contraceptives and acid-reducing agents without dose modifications for either drug.

Metoprolol for the Prevention of Acute Exacerbations of COPD

BACKGROUND

Observational studies suggest that beta-blockers may reduce the risk of exacerbations and death in patients with moderate or severe chronic obstructive pulmonary disease (COPD), but these findings have not been confirmed in randomized trials.

METHODS

In this prospective, randomized trial, we assigned patients between the ages of 40 and 85 years who had COPD to receive either a beta-blocker (extended-release metoprolol) or placebo. All the patients had a clinical history of COPD, along with moderate airflow limitation and an increased risk of exacerbations, as evidenced by a history of exacerbations during the previous year or the prescribed use of supplemental oxygen. We excluded patients who were already taking a beta-blocker or who had an established indication for the use of such drugs. The primary end point was the time until the first exacerbation of COPD during the treatment period, which ranged from 336 to 350 days, depending on the adjusted dose of metoprolol.

RESULTS

A total of 532 patients underwent randomization. The mean (±SD) age of the patients was 65.0±7.8 years; the mean forced expiratory volume in 1 second (FEV1) was 41.1±16.3% of the predicted value. The trial was stopped early because of futility with respect to the primary end point and safety concerns. There was no significant between-group difference in the median time until the first exacerbation, which was 202 days in the metoprolol group and 222 days in the placebo group (hazard ratio for metoprolol vs. placebo, 1.05; 95% confidence interval [CI], 0.84 to 1.32; P = 0.66). Metoprolol was associated with a higher risk of exacerbation leading to hospitalization (hazard ratio, 1.91; 95% CI, 1.29 to 2.83). The frequency of side effects that were possibly related to metoprolol was similar in the two groups, as was the overall rate of nonrespiratory serious adverse events. During the treatment period, there were 11 deaths in the metoprolol group and 5 in the placebo group.

CONCLUSIONS

Among patients with moderate or severe COPD who did not have an established indication for beta-blocker use, the time until the first COPD exacerbation was similar in the metoprolol group and the placebo group. Hospitalization for exacerbation was more common among the patients treated with metoprolol. (Funded by the Department of Defense; BLOCK COPD ClinicalTrials.gov number, NCT02587351.).

Impact of metoprolol standard dosing pathway in Chinese patients with acute coronary syndrome: protocol for a multicentre prospective study

INTRODUCTION

Metoprolol is the most frequently used β-receptor blockers; however, the prescribed dose in China is far less than the recommended doses in the guidelines. Based on the Chinese and International guidelines and the Chinese clinical practice, we are conducting this study (NCT03413410) to test the feasibility and tolerability of the metoprolol optimal dosing pathway by observing the percentage of patients achieving target dose in Chinese acute coronary syndrome (ACS) patients during hospitalisation.

METHODS AND ANALYSIS

A total of about 1000 patients aged ≥18 years, hospitalised for ACS will be enrolled from ~15 hospital sites in China between February 2018 and April 2019. The percentage of patients achieving the target metoprolol dosage at discharge is the primary endpoint. The secondary endpoints included the following: mean heart rate (HR) and blood pressure (BP) of the patients who have achieved target dose at discharge and during the follow-up period, percentage of patients experiencing bradycardia (HR <50 beats/min), hypotension (BP <90/60 mm Hg) and drug-related temporary heart failure worsening during hospitalisation and 1 month after discharge, respectively. We will also assess the proportion of patients reporting metoprolol-related adverse events and the leading causes for metoprolol discontinuation.

ETHICS AND DISSEMINATION

The study protocol has been approved by the Ethics committee of the Chinese PLA General Hospital (number: S2017-112-01). Study findings will be disseminated through presentations at national and international conferences and submitted for publications in peer-reviewed journals.

TRIAL REGISTRATION NUMBER

ClinicalTrials.gov registry (NCT03413410).

Hypertension Treatment Effects on Orthostatic Hypotension and Its Relationship With Cardiovascular Disease

Although orthostatic hypotension (OH) is often considered a contraindication to blood pressure (BP) treatment, evidence is lacking. We examined the effect of BP goal or initial medication choice on OH in AASK (African American Study of Kidney Disease and Hypertension), a 2×3 factorial trial. Blacks with chronic kidney disease attributed to hypertension were randomly assigned 1 of 2 BP goals: intensive (mean arterial pressure, ≤92 mm Hg) or standard (mean arterial pressure, 102-107 mm Hg) and 1 of 3 initial medications (ramipril, metoprolol, and amlodipine). Postural changes in systolic BP, diastolic BP, or heart rate (HR) were determined after 2 minutes and 45 seconds of standing. OH was assessed each visit and defined using the consensus definition (drop in systolic BP ≥20 mm Hg or diastolic BP ≥10 mm Hg). Median follow-up was 4 years. Outcomes were congestive heart failure, stroke, nonfatal cardiovascular disease (CVD), fatal CVD, any CVD (composite of preceding events), and all-cause mortality. There were 1094 participants (mean age, 54.5±10.7 years; 38.8% female; OH was assessed at 52 864 visits). Mean seated systolic BP, diastolic BP, and HR were 150.3±23.9 mm Hg, 95.5±14.2 mm Hg, and 72.0±12.6 bpm, respectively. A more intensive BP goal did not alter the distributions of standing BP and was not associated with OH, but metoprolol was associated with systolic OH compared with ramipril (odds ratio, 1.68; 95% CI, 1.15-2.46) and amlodipine (odds ratio, 1.94; 95% CI, 1.09-3.44). Although consensus OH was associated with stroke (HR, 5.01; 95% CI, 1.80-13.92), nonfatal CVD (HR, 2.28; 95% CI, 1.21-4.30), and any CVD event (HR, 2.12; 95% CI, 1.12-3.98), neither BP goal or medication altered this risk. Concerns about causing OH or its CVD consequences should not deter a lower BP goal among adults with chronic kidney disease attributed to hypertension.

A Comparative Study of Carvedilol Versus Metoprolol Initiation and 1-Year Mortality Among Individuals Receiving Maintenance Hemodialysis

BACKGROUND

Carvedilol and metoprolol are the β-blockers most commonly prescribed to US hemodialysis patients, accounting for ∼80% of β-blocker prescriptions. Despite well-established pharmacologic and pharmacokinetic differences between the 2 medications, little is known about their relative safety and efficacy in the hemodialysis population.

STUDY DESIGN

A retrospective cohort study using a new-user design.

SETTING & PARTICIPANTS

Medicare-enrolled hemodialysis patients treated at a large US dialysis organization who initiated carvedilol or metoprolol therapy from January 1, 2007, through December 30, 2012.

PREDICTOR

Carvedilol versus metoprolol initiation.

OUTCOMES

All-cause mortality, cardiovascular mortality, and intradialytic hypotension (systolic blood pressure decrease ≥ 20mmHg during hemodialysis plus intradialytic saline solution administration) during a 1-year follow-up period.

MEASUREMENTS

Survival models were used to estimate HRs and 95% CIs in mortality analyses. Poisson regression was used to estimate incidence rate ratios (IRRs) and 95% CIs in intradialytic hypotension analyses. Inverse probability of treatment weighting was used to adjust for several demographic, clinical, laboratory, and dialysis treatment covariates in all analyses.

RESULTS

27,064 individuals receiving maintenance hemodialysis were included: 9,558 (35.3%) carvedilol initiators and 17,506 (64.7%) metoprolol initiators. Carvedilol (vs metoprolol) initiation was associated with greater all-cause (adjusted HR, 1.08; 95% CI, 1.02-1.16) and cardiovascular mortality (adjusted HR, 1.18; 95% CI, 1.08-1.29). In subgroup analyses, similar associations were observed among patients with hypertension, atrial fibrillation, heart failure, and a recent myocardial infarction, the main cardiovascular indications for β-blocker therapy. During follow-up, carvedilol (vs metoprolol) initiators had a higher rate of intradialytic hypotension (adjusted IRR, 1.10; 95% CI, 1.09-1.11).

LIMITATIONS

Residual confounding may exist.

CONCLUSIONS

Relative to metoprolol initiation, carvedilol initiation was associated with higher 1-year all-cause and cardiovascular mortality. One potential mechanism for these findings may be the increased occurrence of intradialytic hypotension after carvedilol (vs metoprolol) initiation.

Antiarrhythmic drug-induced smell and taste disturbances: A case report and literature review

RATIONALE

Metoprolol and amiodarone are common antiarrhythmic drugs used in clinics throughout the world. The taste and smell alterations induced by antiarrhythmic drugs remain uncommon throughout the world, with less than 10 reported cases.

PATIENT CONCERNS

In this case report, we describe a case of a 73-year-old female, diagnosed with arrhythmias, was treated for metoprolol. At the third week of metoprolol treatment, the patient noticed a qualitative change in her ability to smell, also called dysosmia. After the metoprolol was tapered, her ability to smell was recovered. However, her arrhythmia was getting worse and the patient was given amiodarone. After using amiodarone for about 2 weeks, the patient felt hypogeusia, or loss of taste sensation.

DIAGNOSES

The patient was diagnosed as dysosmia and taste disturbance induced by the antiarrhythmic drugs.

INTERVENTIONS

After noticed the side effects of the antiarrhythmic drugs, we asked the patient to abandon the drugs and have a radiofrequency ablation.

OUTCOMES

Her ability of smell and taste were recovered after withdrawing the antiarrhythmic drugs. Also, in the follow-up appointment, she reported no complaints of smell or taste anymore.

LESSONS

These rare sensory disorders induced by anti-arrhythmic drugs were less documented in past literature. Our case report describes a patient with an arrhythmia who suffered reversible dysosmia and hypogeusia after taking metoprolol and amiodarone, respectively. We conclude that smell and taste disorders should be made aware to patients during the anti-arrhythmic treatment, helping to promote the safety of patients and drug compliance.

[Jaundice and liver injury with cholestatic pattern after treatment with Metoprololsuccinat]

Drug-induced liver injury is a well-known adverse event to numerous medications with clinical presentations from asymptomatic liver enzyme elevation to liver failure. However, liver injury after administration with metoprolol is not common, and only few case reports have been published. This is a case report of an 80-year-old woman with liver injury with cholestatic pattern and jaundice after two months of treatment with Metoprololsuccinat. With no evidence of other disease, liver function normalized in the following months after discontinuation of Metoprololsuccinat.

Evaluation of the safety and efficacy of metoprolol infusion for children and adolescents with hypertensive crises: a retrospective case series

BACKGROUND

Acute severe hypertension occurs infrequently in pediatric patients and, consequently, data on the efficacy and safety of most antihypertensive agents, as well as the adverse events associated with these agents, are very limited in this population. In this case series, we evaluated the use of metoprolol infusion in children with hypertensive emergencies.

METHODS

The study population comprised children younger than 18 years who had been admitted to the pediatric intensive care unit at King Abdullah University Hospital with blood pressure above the 99th percentile for age, height, and sex and who were symptomatic at the time of presentation. Metoprolol was given as an infusion at a dose of 1-5 mcg/kg/min. The rate of decrease in blood pressure, side effects from the medication, and outcome were assessed.

RESULTS

Thirteen patients ranging in age from 2 months to 16 years were included in this study. The initial mean blood pressure was 23-75 mmHg above the 99th percentile for age, height, and sex. Metoprolol was initiated at a dose of 0.5 mcg/kg/min and titrated according to the target blood pressure to a maximum of 5 mcg/kg/min. Mean blood pressure fell by an average of 12.3, 20.4, and 27.1% at 1, 8, and 24 h, respectively, which is consistent with findings on the use of other intravenous medications reported in published studies. The heart rate did not decrease below the normal range for age. There were no significant side effects of the metoprolol infusion. All patients were discharged home with no neurological sequelae secondary to their hypertension.

CONCLUSION

An infusion of metoprolol for a hypertensive emergency is a safe and effective treatment for pediatric patients.

Metoprolol Increases Uric Acid and Risk of Gout in African Americans With Chronic Kidney Disease Attributed to Hypertension

BACKGROUND

There is little evidence guiding selection of nondiuretic, antihypertensive agents with a goal of lowering uric acid (SUA) and minimizing gout risk.

METHODS

In the African American Study of Kidney Disease and Hypertension (AASK) trial, African Americans with chronic kidney disease were randomly assigned to metoprolol (a beta-blocker), ramipril (an angiotensin-converting enzyme inhibitors [ACEi]), or amlodipine (a dihydropyridine calcium-channel blocker). SUA was measured at baseline and 12 months. Gout-related hospitalizations were based on ICD9 codes. Gout-related medication use (GRMs) was based on active prescriptions of allopurinol, colchicine, or probenecid during the baseline visit of the AASK cohort phase. We examined the effect of drug assignment on 12-month SUA (linear regression), gout-related hospitalization (Cox regression), and GRM (logistic regression).

RESULTS

Of the 630 participants, 40% were female with a mean age of 55 years (SD, 10), mean SUA of 8.2 mg/dl (2.0), and mean serum creatinine of 1.8 mg/dl (0.6). After 12 months, metoprolol increased SUA by 0.3 mg/dl, while ramipril or amlodipine had no effect on SUA. Compared to ramipril, metoprolol significantly increased 12-month SUA (0.40; 0.10, 0.70 mg/dl; P = 0.009), nonsignificantly increased risk of gout-related hospitalization (hazard ratio: 3.87; 0.82, 18.26; P = 0.09), and significantly increased the odds of GRM (odds ratio: 1.62; 1.03, 2.54; P = 0.04). While metoprolol was associated with a higher 12-month SUA compared with amlodipine (0.57; 0.18, 0.95; P = 0.004), there was no difference in gout-related hospitalizations or GRM.

CONCLUSIONS

Metoprolol increased SUA and GRM in African American adults. Health professionals treating patients with kidney disease at risk for gout should avoid metoprolol and possibly consider an ACEi.

CLINICAL TRIALS REGISTRATION

Trial Number NCT00582777.

CYP 2D6*4 polymorphism and interindividual response variation to metoprolol in stage 1 hypertensive patients: no association in a rural Indian population?

BACKGROUND/AIM

Genetic polymorphism of CYP2D6 shows diverse pharmacokinetic and pharmacodynamic variation. Therefore, the present work was designed to study the variation in therapeutic responses to metoprolol (MP) in stage 1 hypertensive patients and also aims to verify the association of CYP2D6*4 polymorphism and response variation in an Indian population for the first time.

MATERIALS AND METHODS

Clinically, a total of 119 hypertensive patients and 116 healthy individuals as controls were included. Patients were treated with MP extended release 25 mg tablets once daily for 2 weeks. Reduction in systolic blood pressure, diastolic blood pressure, and pulse rate were recorded before and after the treatment. For genotyping, genotypes of 89 hypertensive patients and 71 healthy controls were investigated for CYP2D6*4 polymorphism.

RESULTS

Based on reduction in systolic blood pressure, 26% of the patients did not respond to the MP treatment. Of the patients that responded, 28% responded very slowly, 35% (19 males, 23 females) responded moderately, and 12% (8 males, 6 females) showed a good response to MP. For genotype analysis, we pooled 89 hypertensive patients and 71 controls. No association was found between CYP2D6*4 polymorphism and MP response.

CONCLUSION

We found no relationship between MP response and CYP2D6*4 genotype in an Indian population in our study.

[Which is the preferred perioperative beta-blocker?]

Guidelines on perioperative cardiovascular evaluation and management of patients undergoing non-cardiac surgery recommend initiation of beta-blocker therapy in at-risk patients who are undergoing intermediate- to high-risk surgery. Continuation of therapy in patients already receiving beta-blockers is also recommended. Recent literature, however, reported an increased risk of perioperative cardiovascular mortality among patients who continued with existing beta-blockade; most patients in this study were using metoprolol. There are important pharmacodynamic and pharmacokinetic differences between various beta-blockers, and these differences may explain the differences in clinical effects. Metoprolol has less beta1 receptor affinity compared with atenolol and bisoprolol, and beta1 receptor polymorphisms affect the clinical effects of metoprolol. Furthermore, metoprolol is dependent on activity of the CYP2D6 liver enzyme, which results in clinically important differences in plasma concentration. It is, therefore, wise to follow the European guidelines and to initiate beta-blocker therapy in the perioperative period with either atenolol or bisoprolol.

Impact of CYP2D6 polymorphisms on clinical efficacy and tolerability of metoprolol tartrate

Metoprolol is a selective β-1 adrenergic receptor blocker that undergoes extensive metabolism by the polymorphic enzyme cytochrome P450 2D6 (CYP2D6). Our objective was to investigate the influence of CYP2D6 polymorphisms on the efficacy and tolerability of metoprolol tartrate. Two hundred and eighty-one participants with uncomplicated hypertension received 50 mg of metoprolol twice daily followed by response-guided titration to 100 mg twice daily. Phenotypes were assigned based on results of CYP2D6 genotyping and copy number variation assays. Clinical response to metoprolol and adverse effect rates were analyzed in relation to CYP2D6 phenotypes using appropriate statistical tests. Heart rate response differed significantly by CYP2D6 phenotype (P < 0.0001), with poor and intermediate metabolizers showing greater reduction. However, blood pressure response and adverse effect rates were not significantly different by CYP2D6 phenotype. Other than a significant difference in heart rate response, CYP2D6 polymorphisms were not determinants of variability in metoprolol response or tolerability.

[Efficacy and safety of bisoprololal in hypertensive patients with cardiovascular disease and chronic obstructive pulmonary disease]

Efficacy and safety of bisoprolol in hypertensive patients with cardiovascular disease and chronic obstructive pulmonary disease. A comparative study on the efficacy and safety of bisoprolol and sustained release metoprolol succinate in patients with arterial hypertension (AH), cardiovascular disease (CVD) and chronic obstructive pulmonary disease (COPD) was conducted. High antihypertensive efficacy and good tolerability of bisoprolol and metoprolol succinate sustained release was shown in hypertensive patients with CVD and COPD. Bisoprolol versus metoprolol succinate sustained release was more effective in reducing the number of PVCs in hypertensive patients with CVD and COPD. After 12 weeks of therapy of bisoprolol there was a trend to reduce the number of patients with concentric left ventricular hypertrophy by 16.6 % (from 83.3% at baseline vs 66.7% after 12 weeks of treatment, p < 0.1). Despite the fact that the identified changes in respiratory function (ERF) in both groups did not reach certainty bisoprolol versus metoprolol succinate sustained-release was a lesser extent influenced the performance of ERF and more - to reduce dyspnea to the evaluation scales Borg and mMRC (delta% = -7.1 in fixed vs delta% = -3.8 in control groups and delta% = -5.6 vs delta% = 0 respectively) in patients with AH, CVD and COPD.

Beta blockers for peripheral arterial disease

BACKGROUND

Beta (β) blockers are indicated for use in coronary artery disease (CAD). However, optimal therapy for people with CAD accompanied by intermittent claudication has been controversial because of the presumed peripheral haemodynamic consequences of beta blockers, leading to worsening symptoms of intermittent claudication. This is an update of a review first published in 2008.

OBJECTIVES

To quantify the potential harmful effects of beta blockers on maximum walking distance, claudication distance, calf blood flow, calf vascular resistance and skin temperature when used in patients with peripheral arterial disease (PAD).

SEARCH METHODS

For this update, the Cochrane Peripheral Vascular Diseases Group Trials Search Co-ordinator searched the Specialised Register (last searched March 2013) and the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library, 2013, Issue 2).

SELECTION CRITERIA

Randomised controlled trials (RCTs) evaluating the role of both selective (β1) and non-selective (β1 and β2) beta blockers compared with placebo. We excluded trials that compared different types of beta blockers.

DATA COLLECTION AND ANALYSIS

Primary outcome measures were claudication distance in metres, time to claudication in minutes and maximum walking distance in metres and minutes (as assessed by treadmill).Secondary outcome measures included calf blood flow (mL/100 mL/min), calf vascular resistance and skin temperature (ºC).

MAIN RESULTS

We included six RCTs that fulfilled the above criteria, with a total of 119 participants. The beta blockers studied were atenolol, propranolol, pindolol and metoprolol. All trials were of poor quality with the drugs administered over a short time (10 days to two months). None of the primary outcomes were reported by more than one study. Similarly, secondary outcome measures, with the exception of vascular resistance (as reported by three studies), were reported, each by only one study. Pooling of such results was deemed inappropriate. None of the trials showed a statistically significant worsening effect of beta blockers on time to claudication, claudication distance and maximal walking distance as measured on a treadmill, nor on calf blood flow, calf vascular resistance and skin temperature, when compared with placebo. No reports described adverse events associated with the beta blockers studied.

AUTHORS' CONCLUSIONS

Currently, no evidence suggests that beta blockers adversely affect walking distance, calf blood flow, calf vascular resistance and skin temperature in people with intermittent claudication. However, because of the lack of large published trials, beta blockers should be used with caution, if clinically indicated.

[Experience in the pre-hospital treatment of acute coronary syndrome with metoprolol succinate]

Patients with acute coronary syndrome and elevated ST segment in the pre-hospital phase were treated with metoprolol succinate (MS) and thrombolytic therapy. Severe and moderate pain decreased by 54.1 and 16.1% respectively within 60 min after MS intake. Systolic (SAP) and diastolic (DAP) arterial pressure dropped by 35.7 and 16.8 mmHg during the same period. The heart rate (HR) decreased by 25.1 beats/min. 21.8 and 25.3% of the patients showed positive dynamics of ST segment 90 and 180 min after intake of MS. The height of the ST segment was normal in 18.4 and 31.0% of the patients respectively. No cases of external heart rupture were documented at autopsy whereas it was a cause of death in 39.1% of the patients given standard thrombolytic therapy. It is concluded that the use of MS starting from the pre-hospital stage in patients with acute coronary syndrome decreases pain intensity. HR, DAP and SAP and helps to prevent heart rupture.

Persistence with nebivolol in the treatment of hypertension: a retrospective claims analysis

OBJECTIVE

Examine drug persistence by evaluating the hazard of discontinuation and of switching to different antihypertensive drugs in patients initiating treatment with a recently approved β-blocker, nebivolol, versus other β-blockers.

METHODS

This retrospective analysis included all patients diagnosed with hypertension in the MarketScan Database (January 2007 - December 2008) with at least two medical claims and no prior β-blocker prescriptions within 6 months of the initial prescription date. Multivariate Cox proportional hazard models (adjusted for baseline differences in demographics, previous use of other antihypertensive medications, initial doses and supply of medication, and number of distinct prescriptions at baseline) were used to assess the hazard of discontinuation, defined as the first prescription gap of ≥30 days, and to assess the hazard of switching to another antihypertensive drug, defined as a prescription fill for another antihypertensive drug within 15 days before and 30 days after discontinuation of the initial β-blocker.

RESULTS

Of the 173,200 patients included in the study population, the adjusted hazard of discontinuation for nebivolol-initiated patients was 8-20% lower than that of patients who initiated treatment with atenolol (hazard ratio [HR] 0.82, p < 0.001), metoprolol (HR 0.91, p < 0.001), carvedilol (HR 0.92, p < 0.001), or other β-blockers (HR 0.80, p < 0.001). The adjusted hazard of nebivolol-treated patients switching to a different antihypertensive medication was 12-22% lower than that of the other four β-blocker cohorts (atenolol: HR 0.80, p < 0.001; metoprolol: HR 0.86, p < 0.001; carvedilol: HR 0.88, p < 0.001; other β-blockers: HR 0.78, p < 0.001). Sensitivity analyses defined discontinuation as prescription gaps of ≥45 days and ≥60 days and showed a lower hazard of discontinuation among patients initiating nebivolol than among patients initiating all other drug cohorts (p < 0.001).

LIMITATIONS

Comparisons of non-randomized treatment groups may be confounded by unobserved differences in patients' baseline characteristics.

CONCLUSIONS

Initiation with nebivolol was associated with greater persistence than initiation with atenolol, carvedilol, metoprolol, or other β-blockers.

[Advantages of quinapril therapy in patients with arterial hypertension and functional class III chronic heart failure with preserved left ventricular ejection fraction]

AIM

To determine advantages of therapy of functional class (FC) I-II chronic heart failure (CHF) with preserved left ventricular (LV) ejection fraction in patients with hypertensive disease (HD) with metoprolol succinate or quinapril and to assess their effect on regulatory-adaptive status.

METHODS

Two hundred patients with I-II FC CHF and LVEF >50% at the background of stage I-II hypertensive disease participated in this study. They were randomized into 2 groups. Group I comprised 104 patients (mean age 52.8+1.9 years) who were prescribed metoprolol succinate 87.7+/-7.6 mg/day. Patients of group 2 (n=96, mean age 55.0+/-1.4 years) were prescribed quinapril 21.0+55 mg/day. Examination at baseline and after 6 months of therapy included 6 min walk test, treadmillometry with assessment of maximal oxygen consumptiion (VO2max), echocardiography, 24 hour blood pressure monitoring, measurement of N-terminal precursor of brain natriuretic peptide (NT-proBNP); test of cardio-respiratory synchronism was used for objective qualitative determination of the state of the ,renin-angiotensin system.

RESULTS

Both drugs improved parameters of LV diastolic function, but only quinapril effectively changed LV structural geometric parameters and systolic function. Only treatment with quinapril was associated with improvement of RAS, elevation of tolerance to physical effort, and increased VO2max. Quinapril more substantially lowered level of NT-proBNP.

CONCLUSION

Quinapril has an advantage over metoprolol succinate in therapy of patients with FC I-II CHF and preserved LF EF at the background of stage I-II HD.

Risk of periodontal disease: is there a correlation with the type of antihypertensive medication?

INTRODUCTION

The purpose of this study was to evaluate the effects of long-term oral antihypertensive treatment using centrally acting sympatho-inhibitory drugs (clonidine) and beta-blockers (metoprolol) on capillary microcirculation in the labial and periodontal mucosa.

METHODS

Sixty subjects were recruited for the study: 20 patients affected by hypertension in treatment with centrally-acting sympatho-inhibitory drugs (64.28 ± 11.78 years); 20 patients in treatment with beta-blockers (62.03 ± 9.84 years) and 20 healthy subjects (62.06 ± 6.72 years). We use the videocapillaroscopic technique to evaluate in vivo the microcirculation of the labial mucosa corresponding to the lower lip and of the periodontal mucosa corresponding to the central superior incisor.

RESULTS

Capillaroscopy revealed a significant increase in the length, diameter, tortuousity and density (P <0.05) of capillaries in patients affected by hypertension in treatment with centrally acting sympatho-inhibitory drugs, while beta-blockers had a lower effect on the labial and periodontal microcirculation compared to the healthy population.

CONCLUSIONS

The capillaroscopic has revealed substantial modifications of the oral microcirculatory pattern in hypertensive patients in treatment with centrally-acting sympatho-inhibitory drugs than with beta-blockers.

Drug overdose with refractory bradycardia and hypotension

BACKGROUND

In the emergency department physicians are often called upon to make decisions with limited information. Often the correct diagnosis and treatment hinge on one piece of information, which may be the key to the entire presentation.

OBJECTIVE

We present a case report of a patient who presented with refractory bradycardia and hypotension who had over-dosed on calcium channel blockers as well as beta blockers. The underlying cause however was myxedema. Were it not for the presence of hypothermia, the correct diagnosis of myxedema secondary to severe hypothyroidism could have been missed. We also briefly review the pathophysiology and treatment of myxedema.

CONCLUSION

We present a case of refractory bradycardia and hypotension in a patient who had overdosed on calcium channel blockers as well as beta blockers. Paying close attention to all the details of the case eventually uncovered the underlying severe hypothyroidism and myxedema. In the emergency department we are always called upon to make decisions with limited information. It is also paying close attention to all of the information presented that allows one to not miss any key pieces central to the final diagnosis.

The effect of nebivolol versus metoprolol succinate extended release on asymmetric dimethylarginine in hypertension

This study sought to determine if metoprolol succinate ER (MET), and nebivolol (NEB), a β1-AR with increased bioavailability of nitric oxide (NO), would have differing effects on plasma asymmetric dimethylarginine concentration in hypertensives. It was hypothesized that NEB, a β1-AR antagonist and β3-AR agonist with NO-releasing properties, and MET, only a β1-AR antagonist, would have different effects on plasma asymmetric dimethylarginine (ADMA) concentration. Forty-one hypertensive subjects randomly received either 50 mg of MET (n = 19) or 5 mg of NEB (n = 22) for 4 weeks followed by 100 mg MET and 10 mg NEB for 4 weeks. ADMA and insulin-like growth factor-1 (IGF-1) were measured by enzyme-linked immunosorbent assay kit; endothelial progenitor cells were estimated using fluorescein-labeled monoclonal antibody to KDR and CD133 receptors; arterial augmentation index was measured by radial tonometry. Baseline systolic/diastolic blood pressure was 155.1 ± 18.7/85.3 ± 12.5 mm Hg for MET subjects and 157.6 ± 20.7/87.1 ± 14.0 mm Hg for NEB subjects. Baseline ADMA was 0.32 ± 0.123 μmol/L in the MET group and 0.4035 ± 0.1378 in the NEB group. ADMA increased 44.78% and 72% in the MET group at weeks 4 and 8 (P < .05 for both), respectively, without increase in the NEB group. At week 8, augmentation index was increased in the MET group (P < .05). IGF-1 and endothelial progenitor cells were unchanged by treatment. Plasma ADMA and augmentation index are increased in a dose-dependent fashion by MET but not with NEB.

[Efficacy and safety of amiodarone and metoprolol in the treatment of ventricular premature beats: a meta-analysis]

OBJECTIVE

To evaluate the efficacy and safety of amiodarone and metoprolol in the treatment of ventricular premature beats.

METHODS

Controlled randomized clinical trials from 1999 through 2009 were retrieved in China HowNet, VIP Web, Pubmed home. Using Rev Man4.2 software provided by Cochrane Collaboration, Meta-analysis was conducted of 30 articles meeting the inclusion criteria involving a total of 1188 patients.

RESULTS

Merged analysis of amiodarone and metoprolol in the treatment of premature ventricular merge showed a comprehensive test results of Z=1.25, P=0.21, OR=1.18, 95%CI: 0.91-1.54; funnel plot analysis suggested the possible presence of publication bias. The comprehensive test of the incidence of adverse reactions in relation to the two drugs resulted in an OR of 1.96 (95%CI: 1.39-2.77), and funnel plot analysis also indicated publication bias.

CONCLUSIONS

The total response rate of amiodarone does not seem to be superior to metoprolol in the treatment of premature ventricular contractions, and amiodarone is associated with higher incidence of adverse reactions.

[Clinical-pharmacoeconomical aspects of ß-adrenoblockers use in patients with ischemic heart disease undergoing coronary artery bypass grafting]

Aim of this study was to assess clinical and pharmacoeconomic effects of long term use of adrenoblockers in patients with ischemic heart disease (IHD) undergoing coronary artery bypass grafting. Patients with IHD (n=294) were included in open, prospective, randomized clinical trial. The follow up period was 3 years. It was noted that long term use of bisoprolol in comparison with atenolol and metoprolol was characterized by more pronounced increase of exercise tolerance, lower rate of angina recurrence and lower expenses for treatment of patients with IHD.

[Hallucinations and vivid dreams by use of metoprolol]

A 71-year-old man had had visual hallucinations and vivid dreams for two years after starting to take metoprolol. When metoprolol was replaced by atenolol the patient's symptoms disappeared within five days. Side-effects of beta-blockers on the central nervous system are relatively uncommon. The mechanisms underlying these side-effects are not fully understood. Lipophilic beta-blockers can cross the blood-brain barrier, whereas hydrophilic beta-blockers cannot. Doctors need to be alerted to the varying side-effects of specific beta-blockers.

Depressed melatonin secretion in patients with nightmares due to beta-adrenoceptor blocking drugs

Nocturnal urinary melatonin excretion was evaluated in six patients with nightmares and hallucinations during treatment with beta-adrenoceptor blocking agents, and compared to six control patients with similar diagnoses and treatment but without such symptoms from the central nervous system (CNS). Nightly melatonin excretion was lower in all cases with nightly CNS-symptoms than in the control patients. The results also suggest drug differences and dose dependency. It is concluded that in predisposed patients CNS side-effects induced by beta-adrenoceptor antagonists are related to depressed nightly melatonin secretion.

Vasospastic phenomena in patients treated with beta-adrenoceptor blocking agents

Twenty-one patients developed Raynaud's phenomenon during treatment with beta-adrenoceptor blocking agents. The vasospastic symptoms were obviously related to the treatment, but their pathogenesis is still controversial. A decrease in cardiac output might explain the phenomenon. According to our very preliminary data an alpha-adrenergic dominance caused by a direct effect on the peripheral circulation seems more probable. Vasospastic symptoms may arise after treatment with both cardioselective and non-selective beta blocking agents. Cautious prescription of beta blocking drugs to patients with preexisting peripheral vascular disease is recommended.