Evaluation of the safety and efficacy of levalbuterol in 2-5-year-old patients with asthma

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.

The burden of exacerbations in mild asthma: a systematic review

Background

Although most patients with asthma have mild disease, data on how mild asthma is defined, and how frequently exacerbations occur in this patient population are scarce, so we aimed to redress this.

Methods

We searched Medline and Medline In-Process (PubMed), and Embase in OVID for English-language publications containing “mild asthma” plus at least one relevant therapy and outcome/keyword, limited to randomised controlled trials (RCTs) and observational studies published between January 1990 and February 2019. Publications were filtered to ensure appropriate data extraction. The main outcomes were the definitions of mild asthma and exacerbations, baseline exacerbation rates and exacerbation data for placebo recipients in prospective studies. Meta-analysis of exacerbation rates was planned.

Findings

Of 4064 articles identified, 64 were included in our review (49 743 subjects); 54 RCTs and 10 observational/other studies. Six main types of definitions of mild asthma were identified. While care was taken to ensure inclusion only of patients with mild asthma, marked heterogeneity was revealed in the definitions of mild asthma and hence the study populations. Reporting of exacerbations also varied widely between studies, precluding meta-analysis. Between 0–22% of patients were hospitalised for asthma or had a severe exacerbation in the previous year, according to baseline data from prospective studies. In RCTs, severe exacerbation rates in placebo recipients taking only short-acting β₂-agonist therapy ranged from 0.20–2.88 per year.

Conclusions

These data provide new evidence of the burden of exacerbations in mild asthma and highlight the need for standardised definitions of mild asthma and of exacerbations to progress further research.

This comprehensive literature review highlights the risk of exacerbations for patients with mild asthmahttps://bit.ly/3cauSb3

Interrupter resistance to measure dose-response to salbutamol in wheezy preschool children

AIM

Using a non-invasive lung function technique (interrupter resistance, Rint), we aimed to determine whether a dose-response to salbutamol could be detected in wheezy preschool children and if so, which dose of salbutamol should be administered to routinely evaluate bronchial reversibility.

METHOD

Wheezy children (3 to <7 years) were enrolled in a prospective multicenter study. Rint was measured at baseline, and after random assignment to a first dose (100 or 200 μg) and a second dose (cumulative dose: 400, 600, or 800 μg) of salbutamol. Data were analyzed using mixed modeling approach with an inhibitory maximal effect (I_max ) model, to account for a sparse sampling design. Simulations were performed to predict the percentage of children with significant Rint reversibility at several doses.

RESULTS

Final results were available in 99 children out of 106 children included. The model adequately fitted the data, showing satisfactory goodness-of-fit plots and a low residual error of 8%. Children with uncontrolled symptoms had lower I_max (ie, showed less reversibility) compared to children with totally/partly controlled symptoms (0.23 vs. 0.31, P < 0.001). Dose to reach 50% of I_max (D₅₀ ) was 51 μg. According to simulations, 88.1% of children with significant reversibility at dose 800 μg would already show significant reversibility at 400 μg.

CONCLUSION

Interrupter resistance was able to measure a dose-response curve to salbutamol in wheezy preschool children, which was similar to that of older patients. Young children require a high dose of salbutamol to correctly assess airway bronchodilator response, especially these with poor symptom control.

A systematic review of adverse drug events associated with administration of common asthma medications in children

Objective

To systematically review the literature and determine frequencies of adverse drug events (ADE) associated with pediatric asthma medications.

Methods

Following PRISMA guidelines, we systematically searched six bibliographic databases between January 1991 and January 2017. Study eligibility, data extraction and quality assessment were independently completed and verified by two reviewers. We included randomized control trials (RCT), case-control, cohort, or quasi-experimental studies where the primary objective was identifying ADE in children 1 month– 18 years old exposed to commercial asthma medications. The primary outcome was ADE frequency.

Findings

Our search identified 14,540 citations. 46 studies were included: 24 RCT, 15 cohort, 4 RCT pooled analyses, 1 case-control, 1 open-label trial and 1 quasi-experimental study. Studies examined the following drug classes: inhaled corticosteroids (ICS) (n = 24), short-acting beta-agonists (n = 10), long-acting beta-agonists (LABA) (n = 3), ICS + LABA (n = 3), Leukotriene Receptor Antagonists (n = 3) and others (n = 3). 29 studies occurred in North America, and 29 were industry funded. We report a detailed index of 406 ADE descriptions and frequencies organized by drug class. The majority of data focuses on ICS, with 174 ADE affecting 13 organ systems including adrenal and growth suppression. We observed serious ADE, although they were rare, with frequency ranging between 0.9–6% per drug. There were no confirmed deaths, except for 13 potential deaths in a LABA study including combined adult and pediatric participants. We identified substantial methodological concerns, particularly with identifying ADE and determining severity. No studies utilized available standardized causality, severity or preventability assessments.

Conclusion

The majority of studies focus on ICS, with adrenal and growth suppression described. Serious ADE are relatively uncommon, with no confirmed pediatric deaths. We identify substantial methodological concerns, highlighting need for standardization with future research examining pediatric asthma medication safety.

Pharmacological approach to wheezing in preschool children

INTRODUCTION

Wheezing disorders are very common during childhood (particularly among preschool children), and represent a significant burden for patients, their families, the healthcare system, and society as a whole. Identifying wheezing phenotypes, and recognizing the risk factors associated with each, may help to predict long-term outcomes, distinguish high-risk children who may benefit from secondary prevention measures, and ensure that the most effective therapy is prescribed for each case.

AREAS COVERED

The main aim of this review is to analyze the characteristics of the drugs currently used to treat wheezing in preschool children, and discuss the results obtained in children with different wheezing phenotypes.

EXPERT OPINION

The continuous or intermittent administration of various oral or inhaled drugs could theoretically be effective in preventing or controlling wheezing in preschool children. However, the optimal management of acute preschool wheezing episodes has not yet been determined mainly because of their phenotypical heterogeneity.

Comparison of levalbuterol and racemic albuterol based on cardiac adverse effects in children

OBJECTIVE

To compare the cardiac effects of levalbuterol with those of racemic albuterol based on changes in heart rate (HR) in pediatric patients.

METHODS

The medical records of hospitalized children ages 1 month to 12 years, who received either levalbuterol or racemic albuterol via nebulizer for 3 consecutive doses between January 2006 and December 2008 were reviewed. The documented HR was collected prior to and after each administered dose of bronchodilator. The primary outcome was the largest percentage of change in HR between groups. Secondary outcomes of comparisons of the number of patients who had more than a 10% change in HR and incidence of tachycardia were included.

RESULTS

A total of 50 patients, 25 in each group, was included in the study. All patients in the racemic albuterol group received 2.5 mg per dose, while most of the patients in the levalbuterol group received 0.63 mg per dose (19 patients, 76%). Only 6 levalbuterol patients received a dose of 1.25 mg. Nineteen of 25 patients (76%) in the levalbuterol group were tachycardic prior to the first recorded dose compared to 15 patients (60%) in the racemic albuterol group (p = 0.36). The median of the largest percentage of change in HR was 4.1% (interquartile range [IQR], 1.8-8.7) in the levalbuterol group compared to 5% (IQR, 1.9-7.8) in the racemic albuterol group (p = 0.763). Four patients in the levalbuterol group experienced an HR increase of more than 10% compared to 5 patients in the racemic albuterol group (p = 1.0).

CONCLUSION

Levalbuterol and racemic albuterol bronchodilator therapies produced similar effects on HR. No clinically significant differences were detected in HR changes between the two treatment groups, despite administration of a larger equipotent albuterol dose in the racemic albuterol group than in the levalbuterol group.

Asthma outcomes: symptoms

BACKGROUND

Respiratory symptoms are commonly used to assess the impact of patient-centered interventions.

OBJECTIVE

At the request of National Institutes of Health (NIH) institutes and other federal agencies, an expert group was convened to propose which measurements of asthma symptoms should be used as a standardized measure in future clinical research studies.

METHODS

Asthma symptom instruments were classified as daily diaries (prospectively recording symptoms between research visits) or retrospective questionnaires (completed at research visits). We conducted a systematic search in PubMed and a search for articles that cited key studies describing development of instruments. We classified outcome instruments as either core (required in future studies), supplemental (used according to study aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an NIH-organized workshop in March 2010 and finalized in September 2011.

RESULTS

Four instruments (3 daily diaries, 1 for adults and 2 for children; and 1 retrospective questionnaire for adults) were identified. Minimal clinically important differences have not been established for these instruments, and validation studies were only conducted in a limited number of patient populations. Validity of existing instruments may not be generalizable across racial-ethnic or other subgroups.

CONCLUSIONS

An evaluation of symptoms should be a core asthma outcome measure in clinical research. However, available instruments have limitations that preclude selection of a core instrument. The working group participants propose validation studies in diverse populations, comparisons of diaries versus retrospective questionnaires, and evaluations of symptom assessment alone versus composite scores of asthma control.

Asthma outcomes: quality of life

BACKGROUND

"Asthma-related quality of life" (QOL) refers to the perceived impact that asthma has on the patient's QOL.

OBJECTIVE

National Institutes of Health institutes and other federal agencies convened an expert group to recommend standardized measures of the impact of asthma on QOL for use in future asthma clinical research.

METHODS

We reviewed published documentation regarding the development and psychometric evaluation; clinical research use since 2000; and extent to which the content of each existing QOL instrument provides a unique, reliable, and valid assessment of the intended construct. We classified instruments as core (required in future studies), supplemental (used according to the study's aims and standardized), or emerging (requiring validation and standardization). This work was discussed at an National Institutes of Health-organized workshop convened in March 2010 and finalized in September 2011.

RESULTS

Eleven instruments for adults and 6 for children were identified for review. None qualified as core instruments because they predominantly measured indicators of asthma control (symptoms and/or functional status); failed to provide a distinct, reliable score measuring all key dimensions of the intended construct; and/or lacked adequate psychometric data.

CONCLUSIONS

In the absence of existing instruments that meet the stated criteria, currently available instruments are classified as either supplemental or emerging. Research is strongly recommended to develop and evaluate instruments that provide a distinct, reliable measure of the patient's perception of the impact of asthma on all of the key dimensions of QOL, an important outcome that is not captured in other outcome measures.

Levosalbutamol for chronic obstructive pulmonary disease: a treatment evaluation

INTRODUCTION

Chronic obstructive pulmonary disease (COPD) is an inflammatory disorder associated with considerable morbidity and mortality. β2-adrenoceptor agonists (β2-agonists) act by stimulating the β2-adrenoceptor present on smooth muscle and other cells in the airways, resulting in bronchodilatation. β2-agonists play a central role in the treatment of breathlessness in patients with COPD. Salbutamol is a chiral drug with (R)- and (S)- isomers. Almost all β2-agonists that are currently used are racemic mixtures of (R)- and (S)-salbutamol.

AREAS COVERED

(R)-salbutamol alone (Xenopex®, generically known as levosalbutamol) is now indicated for the treatment or prevention of bronchospasm with reversible obstructive airway disease. This evaluation demonstrates that (R)-salbutamol provides a beneficial β2-agonist effect at a cellular level and in experimental models of airways disease. Furthermore, we demonstrate that (S)-salbutamol opposes the desirable effects of (R)-salbutamol and can actually cause features of asthma and COPD in vitro and in experimental asthma.

EXPERT OPINION

Despite this strong body of preclinical experimental evidence, (R)-salbutamol has not shown consistent superiority over (S)- or racemic salbutamol in the treatment of patients with COPD.

(R)-salbutamol in the treatment of asthma and chronic obstructive airways disease

INTRODUCTION

Asthma and chronic obstructive pulmonary disease (COPD) are inflammatory disorders that have an increasing prevalence and associated morbidity and mortality. β(2)-adrenoceptor agonists (β(2)-agonists) act by stimulating the β(2)-adrenoceptor present on airway smooth muscle and other cells in the airway, resulting in bronchodilatation. β(2)-agonists are among the most commonly used drugs in the world and remain pivotal in the treatment of symptoms in patients with asthma and COPD. Salbutamol is a chiral drug with (R)- and (S)- isomers. Almost all β(2)-agonists that are used at present are racemic mixtures of (R)- and (S)-salbutamol.

AREAS COVERED

In this review the authors show that (R)-salbutamol alone (generically known as levosalbutamol) provides beneficial β(2)-agonist effects at a cellular level and in experimental models of airways disease. In addition the authors demonstrate that (S)-salbutamol opposes the desirable effects of (R)-salbutamol and can actually cause features of asthma and COPD in vitro and in experimental asthma.

EXPERT OPINION

Despite this strong body of experimental evidence, (R)-salbutamol has not shown consistent superiority over (S)- or racemic salbutamol in human asthma or COPD.

Efficacy of racemic albuterol versus levalbuterol used as a continuous nebulization for the treatment of acute asthma exacerbations: a randomized, double-blind, clinical trial

OBJECTIVE

To compare racemic albuterol (RAC) with levalbuterol (LEV) in continuous form for the treatment of acute pediatric asthma exacerbations in the emergency department.

STUDY DESIGN

Children between the ages of 6 and 17 inclusive were enrolled if they had a history of asthma, presented to the emergency department with an acute asthma exacerbation, and had an initial forced expiratory volume in 1 second (FEV1) <70% predicted. Patients were then randomized to receive either 7.5 mg of RAC or 3.75 mg of LEV over 1 hour, in addition to standard asthma therapies. Spirometry and asthma scoring were performed at the end of the first hour, and a second hour-long nebulization with the same drug was administered if deemed necessary. Spirometry and asthma scoring were again performed and the final disposition was recorded. As a second, optional part of the study, baseline serum albuterol levels were collected on some patients before treatment.

RESULTS

A total of 99 patients completed the study (44 RAC and 55 LEV). Baseline characteristics were similar except that the RAC group had a higher baseline asthma score. Children in the RAC group had a greater improvement in their FEV1 (p = .043) as well as in their asthma scores (p = .01) after 1 hour of continuous treatment compared to the LEV group. The greater improvement in asthma scores was maintained after the second hour of continuous therapy in the RAC group (p = .008) but not for FEV1 measurements (p = .57). There were no differences between groups for changes in heart rate, respiratory rate, oxygen saturation, or rates of admission.

CONCLUSIONS

At the doses used, RAC appears to be superior to LEV with respect to changes in FEV1 and asthma score. There was no significant difference between the drugs with respect to admission rates or side-effect profile.

The impact of GINA suggested drugs for the treatment of asthma on Health-Related Quality of Life: a GA(2)LEN review

Asthma represents a serious global health problem. People of all ages in countries throughout the world are affected by this chronic airway disorder that, when uncontrolled, can place severe limits on daily life and can even be fatal. Asthma cannot be removed, but asthmatic symptoms can be cured; as for many other chronic diseases, pharmacotherapy is important to reduce the risk of asthma-related mortality, decrease disability and improve symptoms and quality of life. The action of antiasthmatic drugs directly contributes to decrease symptoms severity, improve spirometric results, reduce airway hyperresponsiveness and prevent irreversible airway remodelling. Antiasthmatic therapy is necessary for long-term control of asthma symptoms. Asthma and antiasthmatic drugs can influence patient's quality of life: this is why healthcare systems have recently focused on research studies about Health-Related Quality of Life (HRQL) in asthmatic patients. Numerous validated questionnaires are available and many studies have been performed evaluating HRQL in people affected by asthma, thus testifying a great interest in this topic. The aims of the present review are to examine the scientific literature of the last 4 years (January 2004-December 2007) dealing with the impact of asthma treatments suggested by Global Initiative for Asthma guidelines on patients' quality of life, and to identify the unexplored or not fully investigated areas concerning this issue.

Three generations of ongoing controversies concerning the use of short acting beta-agonist therapy in asthma: a review

An increase in asthma mortality in 1960s noted by British authors stirred a debate about the use of beta-adrenergic therapy that has persisted in the medical literature. The cause appears to be isoproterenol and fenoterol overuse. A second debate evolved around the possible deleterious, pro-inflammatory effects, of the albuterol distomer. Most clinical studies showed improved bronchodilatation, but limited benefits from using levalbuterol. Recently, genotyping has uncovered a single nucleotide polymorphism at codon 16 that appears to affect the long term response to both regular and as needed use of albuterol, calling for a new genotype based therapeutic approach in asthma.

Long-term safety study of levalbuterol administered via metered-dose inhaler in patients with asthma

BACKGROUND

Previous studies have raised concerns regarding the safety of regular use of beta2-agonists for treating asthma. Few studies have explored the safety of at least 1 year of use of racemic albuterol, and none have examined long-term dosing of levalbuterol.

OBJECTIVE

To examine the long-term safety of levalbuterol hydrofluoroalkane (HFA) vs racemic albuterol HFA administered via metered-dose inhaler (MDI) in patients with stable asthma.

METHODS

Patients with mild to moderate asthma (mean forced expiratory volume in 1 second [FEVI], 68.3% of predicted) 12 years or older participated in a multicenter, parallel-group, open-label study. Patients were randomized to levalbuterol HFA MDI (90 microg; 2 actuations of 45 microg; n = 496) or racemic albuterol HFA MDI (180 microg; 2 actuations of 90 microg; n = 250) for 52 weeks of 4 times daily dosing. The primary end point was the incidence of postrandomization adverse events. Asthma exacerbations and pulmonary parameters were also assessed.

RESULTS

The overall incidence of adverse events was similar for levalbuterol (72.0%) and racemic albuterol (76.8%). Rates of beta-mediated adverse events, serious adverse events, and discontinuations because of adverse events were low (<15%) and were comparable between groups. Rates of asthma adverse events for levalbuterol and racemic albuterol were 18.3% and 19.6%, respectively. Mean percentage of predicted FEV1 improved after dosing and was stable for both groups.

CONCLUSION

In this trial, up to 52 weeks of regular use of levalbuterol HFA MDI or racemic albuterol HFA MDI was well tolerated, and no deterioration of lung function was detected during the study period.

Diagnosis and treatment of asthma in childhood: a PRACTALL consensus report

Asthma is the leading chronic disease among children in most industrialized countries. However, the evidence base on specific aspects of pediatric asthma, including therapeutic strategies, is limited and no recent international guidelines have focused exclusively on pediatric asthma. As a result, the European Academy of Allergy and Clinical Immunology and the American Academy of Allergy, Asthma and Immunology nominated expert teams to find a consensus to serve as a guideline for clinical practice in Europe as well as in North America. This consensus report recommends strategies that include pharmacological treatment, allergen and trigger avoidance and asthma education. The report is part of the PRACTALL initiative, which is endorsed by both academies.

Levalbuterol for asthma: a better treatment?

The purpose of this review is to determine whether the proinflammatory actions identified in vitro for (S)-albuterol provide a clinically significant therapeutic advantage for levalbuterol over racemic albuterol. Clinical trials evaluating the bronchodilation in chronic and acute asthma provide conflicting evidence. Older trials suggested an advantage for levalbuterol; however, the newer trials have failed to confirm those advantages. Although (S)-albuterol produces increased bronchial hyperresponsiveness in vitro and in animal models, this has not been consistently confirmed in clinical trials; however, the heterogeneity of the trials precludes definitive conclusions. Current clinical trials do not provide evidence of a substantial advantage of levalbuterol over racemic albuterol although the data are insufficient to determine whether subsets of the patient population might benefit from single isomer therapy.

Evaluation of albuterol 1.25 mg and 0.62 mg for nebulization in 6- to 12-year-old children with moderately severe asthma

To assess the efficacy and safety of 2 different strengths of a manufactured albuterol solution for nebulization (AccuNeb(R); DEY, L.P., Napa, Calif), 349 children with moderate to severe asthma were enrolled in this prospective, multicenter, double-blind, placebo-controlled study. For 4 wk, children 6 to 12 y old were randomly assigned to 1.25 mg (A1) or 0.62 mg (A2) albuterol or placebo (P), nebulized 3 times daily for 4 weeks. Pulmonary function and safety were evaluated at weeks 0, 2, and 4 (visits 2-4). Nonparametric tests (Kruskal-Wallis and Wilcoxon's rank-sum) were used to compare treatments. Primary endpoint (week 4, %Delta area under the curve [AUC] forced expiratory volume in 1 sec [FEV(1)]) results for A1, A2, and P were 90.3% x h*, 73.6% x h*, and 34.2% x h. Secondary assessments for A1, A2, and P were as follows: (1) week 2, %DeltaAUC FEV1 (99.5%*h*, 104.5% x h*, and 43.6% x h); (2) maximum FEV1 (28.6%*, 26.3%*, and 13.4%); and (3) duration of effect (116.8 min*, 115.9 min*, and 39.2 min). A2 was more effective in children 10 y of age or younger and in children 11 to 12 y of age who weighed </=40 kg or had less severe asthma; A1 was more effective in children 11 to 12 y of age who weighed >40 kg or had more severe asthma. Adverse events (occurring in 47% of children) were considered unrelated to drug treatment. Observations on electrocardiogram (notably QTc interval) were similar to those for placebo. A1 and A2 appeared effective in improving pulmonary function and were well tolerated in children aged 6 to 12 y.

Evidence based review on levosalbutamol

Salbutamol, the most commonly used bronchodilator, is a chiral drug with R (levosalbutamol) and S-isomers (also known as enantiomer). The commonly used formulation is a racemic mixture that contains equal amounts of both R and S isomers. Levosalbutamol is the therapeutically active isomer and has all the beta 2 agonist activity. Until recently S-salbutamol was considered inert filler in the racemic mixture but animal as well as human studies have shown that S-salbutamol is not inert rather it may have some deleterious effects. Enantioselective metabolism of salbutamol leads to higher and sustained plasma levels of S-salbutamol with repeated dosing. There has been concern that chronic use of racemic salbutamol may lead to loss of effectiveness and clinical deterioration. Formulation of salbutamol containing only R- isomer (levosalbutamol) has been available in international market since last few years. Clinical trials in acute as well as chronic asthma in adults as well as children have shown that it has therapeutic advantage over racemic salbutamol and also is more cost effective. But, large multicenter trials are needed to prove its therapeutic superiority and cost-effectiveness in long term.

(R)-albuterol for asthma: pro [a.k.a. (S)-albuterol for asthma: con]

Is there scientific evidence to support the replacement of the beta-agonist racemic albuterol with levalbuterol--that is, (R)-albuterol? The argument presented further refines the question as "Do we wish to continue to treat asthma with a mixture of albuterol, of which half is an agent with no known benefit--that is, (S)-albuterol--and which may exacerbate the disease?"

Levosalbutamol in the treatment of asthma

With the exception of levosalbutamol, all of the beta2-agonists that are currently in use are racemic mixtures that are composed in equal amounts of (R)- and (S)-enantiomers. Clinical and mechanistic studies have demonstrated that (R)-salbutamol alone provides the beta2-agonist activity that is needed for the relief of bronchoconstriction, as well as the beta2-adrenergically mediated side effects. (S)-Salbutamol, on the other hand, has minimal binding affinity for the beta2-receptor, indicating that its effects are likely to be mediated through another site. Furthermore, there is evidence that (S)-salbutamol opposes the desirable effects of (R)-salbutamol in the racemic mixture and contributes to the development of characteristic features of asthma, such as airway obstruction, bronchial hyperresponsiveness and airway inflammation. Evidence from clinical studies shows delayed recovery from exacerbation of asthma by patients who are exposed to high concentrations of (S)-salbutamol.