The administration of beta2-agonists for paediatric asthma and its adverse reaction in Australian and New Zealand emergency departments: a cross-sectional survey

Asthma and COPD: A Focus on β-Agonists - Past, Present and Future

Asthma has been recognised as a respiratory disorder for millennia and the focus of targeted drug development for the last 120 years. Asthma is one of the most common chronic non-communicable diseases worldwide. Chronic obstructive pulmonary disease (COPD), a leading cause of morbidity and mortality worldwide, is caused by exposure to tobacco smoke and other noxious particles and exerts a substantial economic and social burden. This chapter reviews the development of the treatments of asthma and COPD particularly focussing on the β-agonists, from the isolation of adrenaline, through the development of generations of short- and long-acting β-agonists. It reviews asthma death epidemics, considers the intrinsic efficacy of clinical compounds, and charts the improvement in selectivity and duration of action that has led to our current medications. Important β2-agonist compounds no longer used are considered, including some with additional properties, and how the different pharmacological properties of current β2-agonists underpin their different places in treatment guidelines. Finally, it concludes with a look forward to future developments that could improve the β-agonists still further, including extending their availability to areas of the world with less readily accessible healthcare.

Inhaled Short-Acting Beta Agonist Treatment-Associated Supraventricular Tachycardia in Children: Still a Matter of Concern in Pediatric Emergency Departments?

Inhaled selective short-acting β-2 agonists (SABA), such as salbutamol, are the rescue treatment of choice for the relief of symptoms of acute asthma exacerbations: one of the leading causes of pediatric emergency department admission and hospitalization. Cardiovascular events, including supraventricular arrhythmias, are the most frequent side effects reported with inhaled SABA in children with asthma and are the main reason for a continuing debate about their safety, despite their widespread use. Although supraventricular tachycardia (SVT) is the most common potentially serious dysrhythmia in children, the incidence and risk factor of SVT after SABA administration is currently unknown. We here reported three cases and conducted a review of the literature in an attempt to gain insight into this issue.

Optimising intravenous salbutamol in children: a phase 2 study

OBJECTIVE

The β2-agonists such as salbutamol are the mainstay of asthma management. Pharmacokinetic-pharmacodynamic (PKPD) models to guide paediatric dosing are lacking. We explored the relationship between salbutamol dose, serum concentration, effectiveness and adverse effects in children by developing a PKPD model.

DESIGN

A prospective cohort study of children admitted to hospital with acute asthma, who received intravenous salbutamol.

SETTING

Children were recruited in two cohorts: the emergency departments of two London hospitals or those retrieved by the Children's Acute Transport Service to three London paediatric intensive care units.

PATIENTS

Patients were eligible if aged 1-15 years, admitted for acute asthma and about to receive or receiving intravenous salbutamol.

INTERVENTIONS

Treatment was according to local policy. Serial salbutamol plasma levels were taken. Effectiveness measurements were recorded using the Paediatric Asthma Severity Score (PASS). Toxicity measurements included lactate, pH, glucose, heart rate, blood pressure and arrhythmias. PKPD modelling was performed with non-linear mixed-effect models.

MAIN OUTCOMES

Fifty-eight children were recruited with 221 salbutamol concentration measurements from 54 children. Median (range) age was 2.9 (1.1-15.2) years, and weight was 13.6 (8-57.3) kg. Ninety-five PASS measurements and 2078 toxicity measurements were obtained.

RESULTS

A two-compartment PK model adequately described the time course of salbutamol-plasma concentrations. An E_MAX (maximum drug effect) concentration-effect relationship described PASS and toxicity measures. PKPD simulations showed an infusion of 0.5 µg/kg/min (maximum 20 µg/min) for 4 hours after bolus achieves >90% maximal bronchodilation for 12 hours.

CONCLUSIONS

A paediatric PKPD model for salbutamol is described. An infusion of 0.5 µg/kg/min after bolus achieves effective bronchodilation. Higher rates are associated with greater tachycardia and hyperglycaemia.

Severe lactic acidosis and persistent diastolic hypotension following standard dose of intermittent nebulized salbutamol in a child: a case report

Background

Salbutamol is a selective β2-receptor agonist widely used to treat asthma in both emergency and outpatient settings. However, it has been associated with a broad spectrum of side effects. Lactic acidosis and diastolic hypotension are rarely reported together following intermittent salbutamol nebulization in children, even less so at standard therapeutic doses.

Case presentation

We present the case of a 12-year-old Italian boy, 34 kg body weight, who experienced a serious drug reaction during a moderate asthma exacerbation with associated dehydration (blood urea nitrogen/creatinine 0.25), following intermittent inhaled (0.2 mg at 3-hour intervals—overall 1.4 mg in 24 hours before arrival) and nebulized treatment (3.25 mg at 20-minute intervals in 60 minutes, overall 11.25 mg in our emergency department). The patient developed hyperglycemia (peak concentration 222 mg/dL), hypokalemia (lowest concentration 2.6 mEq/L), electrocardiogram alterations (corrected QT interval 467 ms), long-lasting arterial hypotension despite fluid boluses (lowest value 87/33 mmHg), and elevated blood lactate levels (peak concentration 8.1 mmol/L), following the third nebulized dose. Infections, liver dysfunction, and toxicity following other medications were ruled out. The aforementioned alterations improved within 24 hours after discontinuation of salbutamol.

Conclusions

We reinforce the message that even the use of intermittent nebulized salbutamol for acute moderate asthma can lead to severe transient complications in children. Then, healthcare providers should pay attention not only in emergency settings, to achieve prompt recognition and proper management of this adverse reaction. Careful reassessment could prevent similar reactions.

Incidence of supraventricular tachycardia after inhaled short-acting beta agonist treatment in children

INTRODUCTION

Albuterol can trigger supraventricular tachycardia (SVT). The clinical characteristics, incidence, and risk factors of SVT after inhaled SABA treatment in children are currently unknown. Through review of regional care delivery, we will describe cases of SVT during asthma treatment in hospital-based settings, define the incidence of SVT in our population, and evaluate risk factors of SABA-induced SVT.

METHODS

We identified hospital-based care episodes of children 0-18 years old between 2006 and 2015 recorded in the Intermountain Healthcare EDW with either 1) diagnosis codes for both asthma and SVT or 2) both SABA and adenosine listed as billed medications. Controls were matched with cases by age and sex to determine risk factors for SVT after SABA using conditional logistic regression.

RESULTS

Of 93 care episodes meeting criteria, we found 7 cases of SVT after SABA treatment in 6 patients over 10 years. In our population, the incidence of SVT is 3.9 per 10,000 episodes of SABA treatment, and 5.1 per 10,000 children with asthma receiving hospital-based asthma care. Two episodes of SVT followed treatment with only levalbuterol, three after only albuterol, and two after both albuterol and levalbuterol treatment. Five cases of SVT were converted to sinus rhythm with adenosine, one converted with synchronized electrical cardioversion, and one resolved spontaneously. No cases of SVT led to death. No examined variables were associated with SABA-induced SVT.

CONCLUSIONS

SVT is rare during hospital-based treatment for acute asthma using inhaled SABAs and has low morbidity and mortality.

Intravenous salbutamol for childhood asthma: evidence-based medicine?

Intravenous salbutamol is commonly used to treat children with severe asthma unresponsive to inhaled β2-agonist therapy. However, in this setting, there is little clinical trial data demonstrating its effectiveness. Additionally, there are significant concerns that intravenous salbutamol-dosing recommendations for children with acute asthma are excessive, and unnecessarily raise the potential for adverse reactions, such as lactic acidosis and tachycardia which, by increasing respiratory workload, exacerbate respiratory failure. Here, we review salbutamol clinical pharmacology and toxicology, evidence relating to its use in acute asthma and highlight gaps in the evidence base.

Critical care for pediatric asthma: wide care variability and challenges for study

OBJECTIVES

To describe pediatric severe asthma care, complications, and outcomes to plan for future prospective studies by the Collaborative Pediatric Critical Care Research Network.

DESIGN

Retrospective cohort study.

SETTING

: Pediatric intensive care units in the United States that submit administrative data to the Pediatric Health Information System.

PATIENTS

Children 1-18 yrs old treated in a Pediatric Health Information System pediatric intensive care unit for asthma during 2004-2008.

INTERVENTIONS

None.

MEASUREMENTS AND MAIN RESULTS

Thirteen-thousand five-hundred fifty-two children were studied; 2,812 (21%) were treated in a Collaborative Pediatric Critical Care Research Network and 10,740 (79%) were treated in a non-Collaborative Pediatric Critical Care Research Network pediatric intensive care unit. Medication use in individual Collaborative Pediatric Critical Care Research Network centers differed widely: ipratropium bromide (41%-84%), terbutaline (11%-74%), magnesium sulfate (23%-64%), and methylxanthines (0%-46%). Complications including pneumothorax (0%-0.6%), cardiac arrest (0.2%-2%), and aspiration (0.2%-2%) were rare. Overall use of medical therapies and complications at Collaborative Pediatric Critical Care Research Network centers were representative of pediatric asthma care at non-Collaborative Pediatric Critical Care Research Network pediatric intensive care units. Median length of pediatric intensive care unit stay at Collaborative Pediatric Critical Care Research Network centers was 1 to 2 days and death was rare (0.1%-3%). Ten percent of children treated at Collaborative Pediatric Critical Care Research Network centers received invasive mechanical ventilation compared to 12% at non-Collaborative Pediatric Critical Care Research Network centers. Overall 44% of patients who received invasive mechanical ventilation were intubated in the pediatric intensive care unit. Children intubated outside the pediatric intensive care unit had significantly shorter median ventilation days (1 vs. 3), pediatric intensive care unit days (2 vs. 4), and hospital days (4 vs. 7) compared to those intubated in the pediatric intensive care unit. Among children who received mechanical respiratory support, significantly more (41% vs. 25%) were treated with noninvasive ventilation and significantly fewer (41% vs. 58%) were intubated before pediatric intensive care unit care when treated in a Pediatric Health Information System hospital emergency department.

CONCLUSIONS

Marked variations in medication therapies and mechanical support exist. Death and other complications were rare. More than half of patients treated with mechanical ventilation were intubated before pediatric intensive care unit care. Site of respiratory mechanical support initiation was associated with length of stay.

A pharmacovigilance study on patients of bronchial asthma in a teaching hospital

Objective:

The present study was conducted to monitor adverse drug reactions in patients of bronchial asthma in outpatient department and inpatient department of a university teaching hospital in South Delhi.

Materials and Methods:

About 200 patients irrespective of age and sex with established asthma were interviewed during the time period of January 2006 to April 2006 using structured questionnaire. Naranjo’s adverse drug reaction probability scale was used to assess the adverse drug reactions.

Results:

A total of 15 adverse drug reactions were reported in 13 out of 200 asthmatic patients. Among the 13 patients reported with adverse drug reactions, 5 (38.5%) were male and 8 (61.5%) patients were female. Maximum percentage of ADRs (2 in 15 prescriptions, 13.3%) observed with montelukast, followed by beclomethasone (1 in 12 prescriptions, 8.3%), salbutamol (6 in 109 prescriptions, 5.5%), and ipratropium (3 in 63 prescriptions, 4.8%).

Conclusions:

Montelukast was found to be associated with greater percentage of adverse drug reactions as compared to other antiasthamatics. The above findings are constrained by a small sample size and need to be corroborated by conducting long-term studies using a larger sample size.

Tremor in childhood

Tremor in childhood is not commonly described in the literature; but it is also likely underappreciated. The etiology of childhood tremor encompasses a wide variety of pathologic processes. Tremor may occur in isolation, or in association with other neurologic findings or systemic disorders. This article aims to provide an overview of tremorogenic mechanisms with respect to neuroanatomy and neurophysiology, particularly as they relate to children. Classification of tremors, diagnostic entities in childhood, and treatment will also be discussed. With improved recognition and characterization of childhood tremors, we may gain a better understanding of the pathophysiology of the disease and determine more age-appropriate treatment strategies.

Beta2-agonists for asthma: the pediatric perspective

Inhaled beta-agonists are commonly prescribed for the treatment of wheezing disorders in infants and children. Despite this, there are concerns that these medications have potentially detrimental effects on lung health and symptoms. We will review the ontogeny of beta-agonist receptor and smooth muscle development from fetal life through infancy and childhood as well as the evidence supporting the clinical utility of beta-agonists in wheezing infants and asthmatic children. Finally, the potential detrimental effects of long- and short-acting beta-agonists in infants and children are discussed.

Thyrotoxic Periodic Paralysis in A Hispanic Man after the Administration Of Prednisone

OBJECTIVE

To present a case of thyrotoxic periodic paralysis (TPP) in a Hispanic man and to discuss the potential precipitating mechanisms.

METHODS

We review the clinical and laboratory findings relative to the occurrence of TPP in a 34-year-old Hispanic man, who had been diagnosed as having Graves' disease.

RESULTS

TPP is a rare complication of thyrotoxicosis. The two known triggers of TPP are high carbohydrate intake and rest after strenuous physical activity. Other precipitating factors include ingestion of alcohol, infection, trauma, emotional stress, and exposure to cold. Nonselective beta-adrenergic blocking agents are used as prophylaxis for the paralytic attacks. Glucocorticoids have been used to treat nonresponsive and recurrent episodes. Nevertheless, our patient, a 34-year-old Hispanic man, had received propranolol for 7 days and one single dose of prednisone 2 hours before the onset of the paralysis. In patients with TPP, the Na+/K+-adenosinetriphosphatase (ATPase) pump activity is considerably increased by excess thyroid hormones, resulting in an increased intracellular potassium shift. Insulin activates the Na+/K+-ATPase pump as well; thus, the precipitating effect of a high carbohydrate diet is explained. Glucocorticoids have been shown to increase the number of Na+/K+-ATPase molecules in skeletal muscle. They also increase insulin secretion in the basal state and the first-phase insulin release after a glucose load.

CONCLUSION

In our patient with TPP, the onset of the attack was not prevented by the use of propranolol and was likely triggered by the administration of prednisone.

A survey of consultant practice: intravenous salbutamol or aminophylline for acute severe childhood asthma and awareness of potential hypokalaemia

British Thoracic Society guidelines recommend intravenous salbutamol or aminophylline for acute severe asthma in children. In the survey reported here, 133 consultant paediatricians completed a questionnaire aimed at evaluating their choice of intravenous bronchodilator for acute severe asthma and their awareness of subsequent hypokalaemia. Of the non-Paediatric Intensive Care Unit (PICU) consultants who responded, 82%, including respiratory paediatricians, reported using aminophylline; in contrast, PICU consultants were significantly more likely to use salbutamol (p=<0.001). There was a lack of awareness that hypokalaemia occurs with aminophylline: 50% of the consultants suggested that hypokalaemia was rare or did not occur. Consultants using intravenous aminophylline were significantly less likely to recheck serum potassium levels than those using intravenous salbutamol (p=0.03). Based on the completed questionnaires, salbutamol infusions are rarely used outside the PICU, and the awareness of potential hypokalaemia following intravenous bronchodilator treatment is variable. It would appear, therefore, that standardised clinical practice is required in order to recognise and treat potential hypokalaemia.

Protocol-based titration of intravenous terbutaline decreases length of stay in pediatric status asthmaticus

Although frequently used to treat status asthmaticus in children, intravenous (IV) terbutaline has not been shown to decrease hospital length of stay (LOS). We theorized that this lack of demonstrable benefit resulted from variations in dosing and titration, rather than the drug per se, and that intensive care unit (ICU) LOS would be shortened by the administration of terbutaline according to a protocol incorporating a quantitative assessment of severity of illness. We prospectively treated 20 consecutive children with status asthmaticus with IV terbutaline according to a protocol that titrated the dose based on a clinical asthma score, the Modified Pulmonary Index Score (MPIS). Data were compared to a historic cohort of the previous 20 consecutive ICU patients with status asthmaticus who were treated with IV terbutaline prior to initiation of the protocol. Patients who received terbutaline by standardized protocol had significantly shorter ICU LOS (3.5 +/- 1.1 vs. 5.0 +/- 2.0 days, P = 0.01), shorter hospital LOS (5.5 +/- 1.3 vs. 8.3 +/- 2.7 days, P < 0.01), and reduced hospital charges ($19,298 +/- $10,516 vs. $26,528 +/- $12,328, P = 0.04). The method of administration of IV terbutaline significantly influenced ICU length of stay and hospital charges.

Variables associated with recovery from acute exacerbations of chronic bronchitis and chronic obstructive pulmonary disease

OBJECTIVE

To identify risk factors for late recovery and failure after ambulatory treatment of exacerbations of chronic bronchitis (CB) and chronic obstructive pulmonary disease (COPD).

METHODS

Observational, non-randomised study of risk factors carried out in 2001 and 2002 in Primary Care practices. Patients aged 40 or older diagnosed with an exacerbation of CB or COPD of probable bacterial etiology were included in the study and followed up for 10 days. Patients were treated with amoxicillin plus clavulanic acid (co-amoxiclav) 500-125 mg tds for 10 days, clarithromycin 500 mg bd for 10 days or moxifloxacin 400 mg od for 5 days.

RESULTS

Two hundred and fifty-two general practitioners participated, registering 1147 valid patients. The rate of failure at day 10 was 15.1% without significant differences among the antibiotic treatments. Median time to recovery was 5 days. Factors significantly associated with late recovery (>5 days) on multivariate analysis were: use of long-term oxygen (OR=1.96; 95%CI=1.35-2.85); use of short-acting beta-2 agonists (OR=1.51; 1.17-1.92). The use of moxifloxacin had a "protective" effect against late recovery compared to co-amoxiclav (OR=0.34; 0.26-0.45) and clarithromycin (OR=0.41; 0.31-2.85). Factors associated with therapeutic failure were: previous hospitalisation (OR=1.61; 1.08-2.42); and 2 or more exacerbations the previous year (OR=1.51; 1.04-2.17); criteria of CB had a protective effect against failure (OR=0.53; 0.35-0.79).

CONCLUSIONS

There are readily identifiable risk factors for ambulatory treatment failure of exacerbations of CB and COPD. In addition, long-term oxygen therapy and short-acting beta-2 agonists are associated with late recovery, and the use of moxifloxacin compared with co-amoxiclav and clarithromycin is associated with faster recovery of symptoms.

Dexamethasone treatment causes resistance to insulin-stimulated cellular potassium uptake in the rat

Patients treated with glucocorticoids have elevated skeletal muscle ouabain binding sites. The major Na(+)-K(+)-ATPase (NKA) isoform proteins found in muscle, alpha2 and beta1, are increased by 50% in rats treated for 14 days with the synthetic glucocorticoid dexamethasone (DEX). This study addressed whether the DEX-induced increase in the muscle NKA pool leads to increased insulin-stimulated cellular K+ uptake that could precipitate hypokalemia. Rats were treated with DEX or vehicle via osmotic minipumps at one of two doses: 0.02 mg.kg(-1).day(-1) for 14 days (low DEX; n = 5 pairs) or 0.1 mg.kg(-1).day(-1) for 7 days (high DEX; n = 6 pairs). Insulin was infused at a rate of 5 mU.kg(-1).min(-1) over 2.5 h in conscious rats. Insulin-stimulated cellular K+ and glucose uptake rates were assessed in vivo by measuring the exogenous K+ infusion (K+(inf)) and glucose infusion (Ginf) rates needed to maintain constant plasma K+ and glucose concentrations during insulin infusion. DEX at both doses decreased insulin-stimulated glucose uptake as previously reported. Ginf (in mmol.kg(-1).h(-1)) was 10.2 +/- 0.6 in vehicle-treated rats, 5.8 +/- 0.8 in low-DEX-treated rats, and 5.2 +/- 0.6 in high-DEX-treated rats. High DEX treatment also reduced insulin-stimulated K+) uptake. K+(inf) (in mmol.kg(-1).h(-1)) was 0.53 +/- 0.08 in vehicle-treated rats, 0.49 +/- 0.14 in low-DEX-treated rats, and 0.27 +/- 0.08 in high-DEX-treated rats. DEX treatment did not alter urinary K+ excretion. NKA alpha2-isoform levels in the low-DEX-treated group, measured by immunoblotting, were unchanged, but they increased by 38 +/- 15% (soleus) and by 67 +/- 3% (gastrocnemius) in the high-DEX treatment group. The NKA alpha1-isoform level was unchanged. These results provide novel evidence for the insulin resistance of K+ clearance during chronic DEX treatment. Insulin-stimulated cellular K+ uptake was significantly depressed despite increased muscle sodium pump pool size.