Cardiovascular adverse drug reaction associated with combined beta-adrenergic and calcium entry-blocking agents

Use of Diltiazem in Chronic Rate Control for Atrial Fibrillation: A Prospective Case-Control Study

Atrial fibrillation (AF) is a multifaceted disease requiring personalised treatment. The aim of our study was to explore the prognostic impact of a patient-specific therapy (PT) for rate control, including the use of non-dihydropyridine calcium channel blockers (NDDC) in patients with heart failure (HF) or in combination with beta-blockers (BB), compared to standard rate control therapy (ST), as defined by previous ESC guidelines. This is a single-centre prospective observational registry on AF patients who were followed by our University Hospital. We included 1112 patients on an exclusive rate control treatment. The PT group consisted of 125 (11.2%) patients, 93/125 (74.4%) of whom were prescribed BB + NDCC (±digoxin), while 85/125 (68.0%) were HF patients who were prescribed NDCC, which was diltiazem in all cases. The patients treated with a PT showed no difference in one-year overall survival compared to those with an ST. Notably, the patients with HF in ST had a worse prognosis (p < 0.001). To better define this finding, we performed three sensitivity analyses by matching each patient in the PT subgroups with three subjects from the ST cohort, showing an improved one-year survival of the HF patients treated with PT (p = 0.039). Our results suggest a potential outcome benefit of NDCC for rate control in AF patients, either alone or in combination with BB and in selected patients with HF.

High-Throughput Drug Screening System Based on Human Induced Pluripotent Stem Cell-Derived Atrial Myocytes ∼ A Novel Platform to Detect Cardiac Toxicity for Atrial Arrhythmias

Evaluation of proarrhythmic properties is critical for drug discovery. In particular, QT prolongation in electrocardiograms has been utilized as a surrogate marker in many evaluation systems to assess the risk of torsade de pointes and lethal ventricular arrhythmia. Recently, new evaluation systems based on human iPS cell-derived cardiomyocytes have been established. On the other hand, in clinical situations, it has been reported that the incidence of atrial arrhythmias such as atrial fibrillation has been increasing every year, with the prediction of a persistent increase in the near future. As to the increased incidence of atrial arrhythmias, in addition to the increased population of geriatric patients, a wide variety of drug treatments may be related, as an experimental method to detect drug-induced atrial arrhythmia has not been established so far. In the present study, we characterized the atrial-like cardiomyocytes derived from human induced pluripotent stem cells and examined their potential for the evaluation of drug-induced atrial arrhythmia. Atrial-like cardiomyocytes were induced by adding retinoic acid (RA) during the process of myocardial differentiation, and their characteristics were compared to those of RA-free cardiomyocytes. Using gene expression and membrane potential analysis, it was confirmed that the cells with or without RA treatment have atrial or ventricular like cardiomyocytes, respectively. Using the ultra-rapid activating delayed rectifier potassium current (I_Kur) channel inhibitor, which is specific to atrial cardiomyocytes, Pulse width duration (PWD) 30cF prolongation was confirmed only in atrial-like cardiomyocytes. In addition, ventricular like cardiomyocytes exhibited an early after depolarization by treatment with rapidly activating delayed rectifier potassium current (I_Kr) channel inhibitor, which induces ventricular arrhythmia in clinical situations. Here, we have established a high-throughput drug evaluation system using human iPS cell-derived atrial-like cardiomyocytes. Based on the obtained data, the system might be a valuable platform to detect potential risks for drug-induced atrial arrhythmias.

[Availability of a novel cardiotoxicity evaluation system using human induced pluripotent stem cell-derived atrial-like myocytes]

It is reported that the incidence of atrial arrhythmias has been increasing year by year and it might increase from now on. Although not only aging but pharmaceutical drug treatments might relate to atrial arrhythmias, experimental method to detect drug-induced atrial arrhythmias has not been established so far. Therefore, we induced differentiation of atrial-like cardiomyocytes from human induced pluripotent stem (iPS) cell, and clarified their characteristics and verified their dug responsiveness. Atrial-like cardiomyocytes were induced by adding retinoic acid (RA) during the process of myocardial differentiation, and their character was compared to RA-untreated cardiomyocytes. In gene expression and membrane potential analysis, it was confirmed that the cells with or without RA treatment have the characters of atrial or ventricular like cardiomyocytes, respectively. In addition, it was also confirmed that atrial-like cardiomyocytes induced reentry-like conduction disorder, which is atrial arrhythmias. Furthermore, as a result of examining the responsiveness of various ion channel inhibitors using these cells, the inhibition of ultra-rapid delayed rectifier potassium current (I_Kur) specifically existed in atrial muscle induced prolongation of PWD30cF (membrane potential duration at 30% depolarization corrected by Fridericia formula) only in atrial-like cardiomyocytes. In addition, ventricular-like cardiomyocytes alone exhibited an early after depolarization by treatment of rapid rectifier potassium current (I_Kr) inhibitor which induced ventricular arrhythmia in clinical situation. Based on above evidences, current evaluation systems using human iPS cell-derived atrial-like cardiomyocytes might be a valuable tool for drug-induced atrial arrhythmias.

Frequency of "on-label" use of intravenous diltiazem for rate control in patients with acute-onset atrial fibrillation or atrial flutter

Purpose

The study was designed to characterize "on-label" use of i.v. diltiazem in patients with acute atrial fibrillation or flutter (AFF).

Methods

An IRB-approved, single-center, retrospective, observational design was used. Eligible patients had acute AFF with heart rate >120 bpm and received i.v. diltiazem from June 1, 2012, to June 30, 2014. The primary outcome was frequency of on-label use of i.v. diltiazem, defined as use of at least one FDA-approved weight-based bolus dose followed by an infusion, if appropriate, in the absence of contraindications.

Results

A total of 300 patients were screened; 97 patients were included for analysis. I.V. diltiazem was used on-label in only 14 patients (14%). Of the 96 patients who received an initial diltiazem bolus injection, the median dose was significantly higher in patients for whom the diltiazem dose was on-label, as follows: 17.5 mg (interquartile range [IQR]), 10-20 mg vs. 10.0 mg (IQR, 10-20 mg), p < 0.02). Twenty-nine patients (35%) in the off-label group had a therapeutic response to diltiazem alone compared with 8 patients (57%) in the on-label group (p = 0.11). More patients treated with off-label diltiazem bolus injection required additional rate control medications (41% vs. 7%, p < 0.04).

Conclusion

In most patients, i.v. diltiazem was not used in accordance with FDA labeling. For most, i.v. diltiazem doses were lower than recommended and many of these patients required additional rate control medications to achieve a therapeutic response.

Beta-blocker use and risk of symptomatic bradyarrhythmias: a hospital-based case-control study

OBJECTIVE

To investigate the risk factors of symptomatic bradyarrhythmias in relation to β-blockers use.

METHODS

A hospital-based case-control study [228 patients: 108 with symptomatic bradyarrhythmias (cases) and 120 controls] was conducted in Sultanah Aminah Hospital, Malaysia between January 2011 and January 2014.

RESULTS

The mean age was 61.1 ± 13.3 years with a majority of men (68.9%). Cases were likely than control to be older, hypertensive, lower body mass index and concomitant use of rate-controlling drugs (such as digoxin, verapamil, diltiazem, ivabradine or amiodarone). Significantly higher level of serum potassium, urea, creatinine and lower level of estimated glomerular filtration rate (eGFR) were observed among cases as compared to controls. On univariate analysis among patients on β-blockers, older age (crude OR: 1.07; 95% CI: 1.03-1.11, P = 0.000), hypertension (crude OR: 5.6; 95% CI: 1.51-20.72, P = 0.010), lower sodium (crude OR: 0.04; 95% CI: 0.81-0.99, P = 0.036), higher potassium (crude OR: 2.36; 95% CI: 1.31-4.26, P = 0.004) and higher urea (crude OR: 1.23; 95% CI: 1.11-1.38, P = 0.000) were associated with increased risk of symptomatic bradyarrhythmias; eGFR was inversely and significantly associated with symptomatic bradyarrhythmias in both 'β-blockers' (crude OR: 0.97; 95% CI: 0.96-0.98, P = 0.000) and 'non-β-blockers' (crude OR: 0.99; 95% CI: 0.97-0.99, P = 0.023) arms. However, eGFR was not significantly associated with symptomatic bradyarrhythmias in the final model of both 'β-blockers' (adjusted OR: 0.98; 95% CI: 0.96-0.98, P = 0.103) and 'non-β-blockers' (adjusted OR: 0.99; 95% CI: 0.97-1.01, P = 0.328) arms. Importantly, older age was a significant predictor of symptomatic bradyarrhythmias in the 'β-blockers' as compared to the 'non-β-blockers' arms (adjusted OR: 1.09; 95% CI: 1.03-1.15, P = 0.003 vs. adjusted OR: 1.03; 95% CI: 0.98-1.09, P = 0.232, respectively).

CONCLUSION

Older age was a significant predictor of symptomatic bradyarrhythmias in patients on β-blockers than those without β-blockers.

Hypertension treatment and outcomes in US nursing homes: results from the US National Nursing Home Survey

OBJECTIVES

The objective of this study was to describe antihypertensive medication use, determine what effects comorbid illness has on prescribing of commonly used antihypertensive medications, and explore how treatment affected selected clinical and functional outcomes in US nursing home residents.

DESIGN

Cross-sectional observational study using data from the 2004 National Nursing Home Survey, a nationally representative sample of US nursing home residents.

RESULTS

More than one half, 53.8%, of all residents had hypertension as a primary admission or current diagnosis. A large majority (84%) of residents with the diagnosis of hypertension were receiving at least one legend medication indicated for hypertension. The most common selection of pharmacologic agent was monotherapy with diuretics in 11% of all residents receiving antihypertensive medications. Hypertensive residents with a diagnosis of arrhythmia (odds ratio [OR] = 1.19, 95% confidence interval [CI] = 1.02-1.38), stroke (OR = 1.18, 95% CI = 1.05-1.34), or heart failure (OR = 1.17, 95% CI = 1.04-1.32) were more likely to be receiving a beta blocker. Those with diabetes (OR = 0.86, 95% CI = 0.77-0.96), depression (OR = 0.78, 95% CI = 0.70-0.87), constipation (OR = 0.72, 95% CI = 0.61-0.84), or asthma (OR = 0.51, 95% CI = 0.34-0.74) were less likely to be receiving a beta blocker. Hospital admission was less likely (OR = 0.50, 95% CI = 0.36-0.69) when residents were taking any commonly used antihypertensive medication (diuretics, beta blockers, angiotensin-converting enzyme/angiotensin receptor blockers [ACE/ARBs], calcium channel blockers, or alpha-blockers) but significantly more likely when therapy included a beta blocker (OR = 1.45, 95% CI = 1.18 - 1.78). Beta blockers were associated with an increased likelihood of falls (OR = 1.14, 95% CI = 1.04-1.27) and a decreased likelihood of constipation (OR 0.72, 95% CI = 0.61-0.84). Beta blockers were associated with a decreased likelihood of depression (OR 0.83, 95% CI = 0.74-0.92) as was the use of any commonly used antihypertensive (OR = 0.76, 95% CI = 0.63-0.90).

CONCLUSION

Hypertension is prevalent in US nursing home residents and most residents with that diagnosis (84%) are being treated with antihypertensive medication. Through examination of the National Nursing Home Survey database, associations between the use of selected antihypertensive medication, comorbid illness, and specified outcomes were observed.

Prognosis and natural history of drug-related bradycardia

Background and Objectives

The prognosis and natural history of bradycardia related to drugs such as beta-blockers and non-dihydropyridine calcium channel blockers are not well known.

Subjects and Methods

We retrospectively analyzed 38 consecutive patients (age 69±11, 21 women) with drug-related bradycardia (DRB) between March 2005 and September 2007. A drug-associated etiology for the bradycardia was established based on the medical history and patient response to drug discontinuation. The mean follow-up duration was 18±8 months.

Results

The initial electrocardiogram (ECG) showed sinus bradycardia (heart rate ≤40/min) in 13 patients, sinus bradycardia with junctional escape beats in 18 patients, and third-degree atrioventricular (AV) block in seven patients. Drug discontinuation was followed by resolution of bradycardia in 60% of patients (n=23). Among them, five (17.8%) patients resumed taking the culprit medication after discharge and none developed bradycardia again. Bradycardia persisted in 10 (26.3%) patients despite drug withdrawal, and a permanent pacemaker was implanted in seven of them. Third-degree AV block, QRS width, and bradycardia requiring temporary transvenous pacing were significantly associated with the bradycardia caused by drugs.

Conclusion

Beta-blockers were the most common drugs associated with DRB. However, in one quarter of the cases the DRB was not associated with drugs; in these patients permanent pacemaker implantation should be considered.

Secondary stroke prevention strategies for the oldest patients: possibilities and challenges

Older adults are not only at higher risk of experiencing stroke, but also have multiple co-morbidities that make treatment for secondary stroke prevention challenging. Very few clinical trials specifically related to secondary stroke prevention treatment efficacy have focused on the oldest-old (>or=85 years) and, therefore, evidence-based recommendations for treatment specific to this population are not available. Some of the special considerations for stroke prevention treatments in older patients include careful titration of blood-pressure-lowering drugs to avoid hypotension, the risk of haemorrhagic stroke with HMG-CoA reductase inhibitors (statins) and weighing the risk of recurrent ischaemia versus bleeding in patients taking antiplatelet or anticoagulant therapy. The risk of peri-procedural complications appears to be high with both carotid angioplasty and stenting and carotid endarterectomy in older patients with carotid stenosis. Other common issues in older patients include adverse drug events, recognizing the risk of dementia, depression and osteoporosis and deciding when to discontinue secondary stroke prevention. In this review, we provide the practitioner with the evidence related to specific approaches to secondary stroke prevention in older patients, and identify the knowledge gaps that currently limit our ability to appropriately treat this vulnerable population.

Evaluation of adverse drug reactions reported to a poison control center between 2000 and 2007

PURPOSE

The likelihood of hospitalization caused by adverse drug reactions (ADRs) from commonly implicated therapeutic groups is discussed.

METHODS

A retrospective analysis of the computerized records of exposure cases involving pharmaceutical substances reported to the New Jersey Poison Information and Education System (NJPIES) was conducted from 2000 through 2007. The cases in the National Poisoning Data System that were categorized as an ADR were included in the study set. Only reports involving a single drug were selected for inclusion in the analyses. Characteristics of the ADRs, such as the sex and age of the patient, the therapeutic group involved, and the medical outcome of the exposure, were examined. Reports of ADRs with the most frequently implicated therapeutic groups were analyzed based on whether the patients were managed onsite, referred to a health care facility, or managed at a health care facility. The Adverse Drug Reaction Hospitalization (ADRH) index was calculated for all therapeutic groups, but the focus of the analyses was on the groups that were implicated in 5% or more of all ADRs.

RESULTS

A total of 454,520 cases of human poisoning exposure were reported to NJPIES from 2000 through 2007. Of these cases, 162,105 were exposures implicating a single drug, of which 5,461 (3.4%) were classified as an ADR. Of the 5,461 cases, 385 patients were admitted into a health care facility. Antidepressants had the highest ADRH index (20.4%) among the therapeutic groups implicated, and antimicrobials had the lowest (2.2%).

CONCLUSION

The analyses revealed a substantial variation in the likelihood of hospitalization associated with ADRs within different therapeutic groups. Among the groups that were most frequently implicated in ADRs, antidepressants showed the highest probability for an ADR-related hospitalization, followed by dietary supplements, herbals, and homeopathics and then by sedatives, hypnotics, and antipsychotics.

Prevalence of adverse drug combinations in a large post-mortem toxicology database

The prevalence of important adverse drug combinations was studied among the 37,367 cases included in the Finnish post-mortem toxicology database during 2000-2006. The new SFINX interaction database (Swedish, Finnish, INteraction X-referencing) was utilised to identify adverse drug combinations. Consequently, the 24 drugs chosen for the study generated 96 two-compound combinations possessing potentially severe interactions. The total number of hits for the combinations found in the post-mortem database was 267, which accounts for approximately 0.71% of all cases. The potential role of adverse drug interaction (ADI) in these cases was evaluated from the background information and death certificate. The possible ADI cases comprised 23% of all hits and 0.17% of all cases analysed. In cases with a pharmacodynamic mechanism, the most prominent combinations were medicines causing serotonin syndrome or a beta(1)-blocker with verapamil or diltiazem. In cases with a pharmacokinetic mechanism, half of the cases involved digoxin in combination with verapamil. In one third of the possible ADI cases, a forensic pathologist had noted the studied compounds as an underlying or contributing cause of death, although the agents' specific role in ADIs was rarely recognised.

Pharmacokinetics of the calcium-channel blocker diltiazem after a single intravenous dose in horses

The pharmacokinetics of diltiazem were determined in eight healthy horses. Diltiazem HCl, 1 mg/kg i.v., was administered over 5 min. Venous blood samples were collected at regular intervals after administration. Plasma concentrations of diltiazem and desacetyldiltiazem were determined by high-performance liquid chromatography. A second, putative metabolite was detected, but could not be identified due to the lack of an authentic standard. Data were analyzed by nonlinear least-squares regression analysis. The median (minimum-maximum) peak plasma concentration of diltiazem was 727 (539-976) ng/mL. Plasma diltiazem concentration vs. time data were best described by a two-compartment model with first-order drug elimination. The distribution half-life was 12 (6-23) min, the terminal half-life was 93 (73-161) min, the mean residence time was 125 (99-206) min, total plasma clearance was 14.4 (10.4-18.6) mL/kg/min, and the volume of distribution at steady-state was 1.84 (1.46-2.51) L/kg. The normalized ratio of the area under the curve (AUC) of desacetyldiltiazem to the AUC of diltiazem was 0.088 (0.062-0.179). The disposition of diltiazem in horses was characterized by rapid distribution and elimination and a terminal half-life shorter than reported in humans and dogs. Because of the reported low pharmacologic activity, plasma diltiazem metabolite concentrations were not considered clinically important.

Hypertension management: the primary care nursing role

Hypertension is a prevalent chronic illness that is implicated in many cardiovascular diseases. Practice nurses and the district nursing team have a major role to play in its management. In this article, current British Hypertension Society guidelines are presented and discussed with regards to their evidence base. Implications for nursing practice are highlighted.

Efficacy of monotherapy compared with combined antianginal drugs in the treatment of chronic stable angina pectoris: a meta-analysis

OBJECTIVE

To determine the relative efficacy of antianginal drugs administered as monotherapy or in combination in patients with chronic stable angina.

METHODS

A meta-analysis was performed on randomized trials, published in English between 1980 and 1999, that directly compared combined treatment and monotherapy. Twenty-two articles were included, all on the comparison of -blocker monotherapies to their combination with a calcium antagonist and 10 on the comparison of calcium antagonist monotherapies to their combination with a -blocker.

RESULTS

Time to 1 mm ST-segment depression, total exercise duration and time to onset of anginal pain were significantly increased with the combined therapy compared to -blocker alone (by 8, 5 and 12%, respectively). Only time to 1 mm ST-segment depression was significantly increased with the combined therapy compared to calcium antagonist alone (by 9%). For all these parameters, the adjusted differences were significant only within 6 h following drug intake and were not significant after 6 h. No analysis of safety data could be performed.

CONCLUSION

As far as exercise testing is concerned, the combination of a calcium antagonist and a -blocker is statistically more effective than either monotherapy. Further studies are needed to confirm the higher efficacy after the first 6 h following drug intake.