A randomized controlled trial of intravenous montelukast in acute asthma

Efficacy and safety of intravenous leukotriene receptor antagonists in acute asthma

The incidence of bronchial asthma has increased substantially since recent decades in both children and adults. Moreover, the number of patients presenting with asthma exacerbation to the emergency department has also increased in several countries. Leukotrienes are inflammatory mediators that play an important role in bronchial asthma exacerbation. Leukotriene receptor antagonists reduce asthma exacerbation in chronic asthma; moreover, the current guidelines for asthma management recommend the use of oral leukotriene receptor antagonists for asthma control and reduce further exacerbation. However, data on the use of intravenous leukotriene receptor antagonists during acute asthma exacerbation are scarce. Nevertheless, currently available data revealed a trend of significant improvement of acute asthma and rapid reversal of airflow obstruction when administered during an acute asthma attack. This review aims to summarize currently available data on the use of intravenous leukotriene receptor antagonists in adult patients with acute asthma exacerbation.

Montelukast Efficacy for Improvement of Adult Acute Phase Mild-Moderate Asthma Attack: A Clinical Trial Study

Background:

Asthma, an inflammatory disease of the respiratory tract, is one of the most frequent causes of referral to emergency departments. The aim of this study is to evaluate the efficacy of montelukast as a member of LTRAs for the improvement of pulmonary function and clinical symptoms of patients with asthma.

Methods:

The study was conducted on 80 patients with acute mild- moderate asthma, divided randomly into two groups of 40 subjects. A double-blind clinical trial was conducted on asthmatic patients who encounter an acute phase asthma attack. The experimental group received two montelukast 5 mg chewable tablets at arrival, accompanied by standard mild-moderate asthma treatment consisting of oxygen and nebulization with albuterol 2.5 mg and ipratropium bromide 0.5 mg in 3 doses for 60 minutes. The control group received standard mild-moderate asthma treatment plus placebo chewable tablets at the beginning without any leukotriene inhibitors. Pulmonary function tests, hemodynamic variables and Borg Dyspnea Scale were evaluated and analyzed at 0, 30, 60, 90 and 150 minutes in both case and control groups.

Results:

No significant differences were observed between the case and the control group in terms of PEFR and FEV1 measurements during the study at different time points [P > 0.05]. There were no significant differences in terms of hemodynamic variables [blood pressure, pulse and respiration rate, pressure of oxygen in arterial blood] and Borg Dyspnea Scale in both groups as well.

Conclusion:

The study findings showed that the montelukast administration in mild-moderate acute asthma attack setting had no significant impact on pulmonary function tests and clinical symptoms of the studied patients rather than standard asthma treatment.

Pilot Study of Peak Plasma Concentration After High-Dose Oral Montelukast in Children With Acute Asthma Exacerbations

Acute asthma exacerbations are primarily due to airway inflammation and remain one of the most frequent reasons for childhood hospitalizations. Although systemic corticosteroids remain the mainstay of therapy because of their anti-inflammatory properties, not all inflammatory pathways are responsive to systemic corticosteroids, necessitating hospital admission for further management. Cysteinyl leukotrienes (LTs) are proinflammatory mediators that play an important role in systemic corticosteroids non-responsiveness. Montelukast is a potent LT-receptor antagonist, and an intravenous preparation caused rapid, sustained improvement of acute asthma exacerbations in adults. We hypothesized that a 30-mg dose of oral montelukast achieves peak plasma concentrations (C_max ), comparable to the intravenous preparation (1700 ng/mL) and would be well tolerated in 15 children aged 5 to 12 years with acute asthma exacerbations. After administration of montelukast chewable tablets, blood samples were collected at 0, 15, 30, 45, 60, 120, 180, and 240 minutes. Plasma was separated and frozen at -80°C until analysis for montelukast concentration using liquid chromatography- tandem mass spectrometry. Median time to C_max (t_max ) was 3.0 hours. Six participants (40%) achieved C_max of 1700 ng/mL or higher. However, there was high interindividual variability in peak plasma concentration (median C_max of 1378 ng/mL; range, 16-4895 ng/mL). No participant had side effects or adverse events. Plasma concentrations from this pilot study support the design of a weight-based dose-finding study aimed at selecting an optimal dose for future clinical trials to assess the efficacy of high-dose oral montelukast in children with moderate to severe asthma exacerbations.

Pharmacotherapeutic strategies for critical asthma syndrome: a look at the state of the art

INTRODUCTION

'Critical Asthma Syndrome' (CAS) is an umbrella term proposed to include several forms of asthma, responsible for acute and life-threatening exacerbations. CAS requires urgent and adequate supportive and pharmacological treatments to prevent serious outcomes.

AREAS COVERED

The purpose of this review is to discuss current knowledge on the pharmacotherapeutic strategies for treatment of CAS.

EXPERT OPINION

Airflow limitation, airway wall edema, and mucus plugs are the pathophysiological targets of pharmacological therapies. Strategies to achieve these goals are based on the use of various classes of drugs. Inhaled beta2-agonists are the mainstay of the initial therapy of CAS. Inhaled anticholinergic agents may be considered in the treatment of CAS in addition to beta 2 agonists. Systemic corticosteroids should be administered as soon as possible in order to counteract airway inflammation and restore normal airway sensitivity. The effectiveness of pharmacological therapies in CAS is linked not only to the timely use of drugsbut also to the dosage and route of administration. Early recognition and aggressive treatment are essential for the management of CAS; however, prevention is the best cure. Although significant progress has been made, further efforts are needed to implement an optimal exacerbation prevention strategy.

Acute Severe Asthma in Adolescent and Adult Patients: Current Perspectives on Assessment and Management

Asthma is a chronic airway inflammatory disease that is associated with variable expiratory flow, variable respiratory symptoms, and exacerbations which sometimes require hospitalization or may be fatal. It is not only patients with severe and poorly controlled asthma that are at risk for an acute severe exacerbation, but this has also been observed in patients with otherwise mild or moderate asthma. This review discusses current aspects on the pathogenesis and pathophysiology of acute severe asthma exacerbations and provides the current perspectives on the management of acute severe asthma attacks in the emergency department and the intensive care unit.

Montelukast Treatment of Acute Asthma Exacerbations in Children Aged 2 to 5 Years: A Randomized, Double-Blind, Placebo-Controlled Trial

BACKGROUND

Although montelukast has an established role in the management of chronic asthma in children, its efficacy in acute asthma exacerbations (AAEs) in children aged 2 to 5 years is not fully known. This study aimed to evaluate the effectiveness and safety of montelukast for treating AAE in children aged 2 to 5 years in China.

METHODS

In total, 120 Chinese children with AAE, aged 2 to 5 years, were randomly divided into 2 groups, each with 60 patients. All patients received either montelukast or placebo along with standard therapy for acute asthma between January 2011 and December 2015. The outcome measurements included the difference in peak expiratory flow and lung function improvements, as well as adverse events.

RESULTS

A total of 117 patients completed the study. Montelukast showed no greater effectiveness than did placebo in increasing the peak expiratory flow during the period of hospital stay (P = 0.92 at day 2, P = 0.86 at day 3, and P = 0.82 at day 4) and at discharge (P = 0.84). Similarly, the forced expiratory volume in 1 second at discharge also did not show significant difference between the 2 groups (P = 0.80). In addition, no serious adverse events were found during the intervention period of the study.

CONCLUSIONS

The results of this study demonstrate no benefit of montelukast over placebo in the treatment of AAE in a cohort of 2- to 5-year-old children.

Comparison of oral montelukast with oral ozagrel in acute asthma: A randomized, double-blind, placebo-controlled study

Background:

The need for more effective management of acute asthma has led to research on drugs which are otherwise approved for use in chronic asthma.

Objective:

To study and compare the effects of oral montelukast with oral ozagrel in acute asthma.

Materials and Methods:

One hundred and twenty patients with acute asthma were recruited for the study. Out of 120 study patients, forty each were randomized into placebo, montelukast, and ozagrel groups. After the first dose of the drug or placebo was administered, peak expiratory flow rate (PEFR), number of rescue medications and also vital signs were noted at 6 h, 12 h, 24 h, 48 h, and at discharge. In addition, same recordings were done on the morning (8 a.m. – 10 a.m.) following admission. The difference in mean PEFR of each group at above-mentioned time points was the primary endpoint whereas need for rescue medications the secondary end-point.

Results:

The respective mean PEFR recordings of the placebo, montelukast, and ozagrel groups at various time points were as follows: at 6 h (235.19 ± 3.18, 242.86 ± 3.26, 228.18 ± 3.25); at 12 h (254.37 ± 5.23, 265.62 ± 5.38, 242.99 ± 5.36); at 24 h (267.46 ± 7.41, 291.39 ± 7.61, 268.14 ± 7.58); and at 48 h (277.99 ± 7.35, 303.22 ± 7.56, 285.27 ± 7.53); and discharge (301.94 ± 7.07, 317.32 ± 7.27, 298.99 ± 7.23). The mean PEFR between the treatment groups were not statistically significant (P = 0.102). The mean PEFR in the three groups at 8–10 a.m. following admission was 257.60 ± 5.52, 264.23 ± 5.98, and 249.94 ± 5.96; P = 0.266. Total number of rescue doses needed were 7, 4, and 13, respectively (P = 0.67).

Conclusion:

Montelukast or ozagrel when added to the standard treatment of acute asthma does not result in any additional benefit.

Oxidative stress and cellular pathways of asthma and inflammation: Therapeutic strategies and pharmacological targets

Asthma is a complex inflammatory disease characterized by airway inflammation and hyperresponsiveness. The mechanisms associated with the development and progression of asthma have been widely studied in multiple populations and animal models, and these have revealed involvement of various cell types and activation of intracellular signaling pathways that result in activation of inflammatory genes. Significant contributions of Toll-like-receptors (TLRs) and transcription factors such as NF-кB, have been reported as major contributors to inflammatory pathways. These have also recently been associated with mechanisms of oxidative biology. This is of important clinical significance as the observed inefficacy of current available treatments for severe asthma is widely attributed to oxidative stress. Therefore, targeting oxidizing molecules in conjunction with inflammatory mediators and transcription factors may present a novel therapeutic strategy for asthma. In this review, we summarize TLRs and NF-кB pathways in the context of exacerbation of asthma pathogenesis and oxidative biology, and we discuss the potential use of polyphenolic flavonoid compounds, known to target these pathways and possess antioxidant activity, as potential therapeutic agents for asthma.

Effects of oral montelukast on airway function in acute asthma: A randomized trial

Background:

The role of leukotriene receptor antagonist is well known in the management of chronic asthma, but their efficacy in acute exacerbation of asthma is unknown. The present study was done to evaluate the clinical efficacy of oral montelukast as an add on therapy to the usual standard therapy of acute attack of bronchial asthma.

Materials and Methods:

A randomized single-blinded controlled study was conducted in a tertiary care teaching hospital. A total of 162 patients with age >18 years of acute exacerbations due to bronchial asthma were included in the study. The patients were randomized into two study and control groups. The study group patients received oral montelukast (10 mg) once daily for 2 weeks, while the control group received a placebo. All the patients received standard therapy according to GINA guidelines. Improvements in lung function tests, clinical symptoms, and relapse rates were monitored at baseline, 1 week, 2 weeks, and 4 weeks. Side effects profile was also monitored.

Results:

A total of 160 patients were finally assessed. Seventy-eight patients belonged to study group and 82 in the control group. Baseline characteristics were similar and well matched in both groups. Mean age was 39.9 ± 15.8 years in the study group and 42.8 ± 12.8 in the control group and majority were female patients in both groups. At the end of 4 weeks, it was observed that the study group patients who received montelukast had better forced expiratory volume in 1 s (FEV₁) improvement by 21% (0.21 L) as compared to the control group (P < 0.0033). It was also observed that there was a better improvement in peak expiratory flow rate (PEFR) at 2 weeks (0.4 L/s, 12%) and at 4 weeks (0.9 L/s, 23%) as compared to the control group (P < 0.0376 and P < 0.0003 respectively). There was no difference in forced vital capacity (FVC), FEV₁/FVC ratio and relapse rates between the two groups. No serious adverse effects were observed during the study.

Conclusions:

In acute asthma exacerbations, the present study showed that additional administration of oral montelukast resulted in significantly higher FEV₁ at 4 weeks and PEFR at 2 weeks and 4 weeks as compared to the standard treatment alone. These findings should be confirmed by conducting a larger population-based clinical study.

Comparison of oral montelukast with oral zileuton in acute asthma: A randomized, double-blind, placebo-controlled study

Background:

Leukotriene modifiers have an established role in the management of chronic asthma but their role in acute asthma is still under evaluation.

Objective:

To study and compare the effects of oral montelukast with oral zileuton in acute asthma.

Materials and Methods:

This study included 120 asthmatics and was conducted from September 2012 to March 2014. Patients were randomized into three different groups to receive montelukast or zileuton or placebo in addition to standard treatment for asthma exacerbation. Peak expiratory flow rate (PEFR) values, details of rescue medication and vital signs were recorded at 6 h, 12 h, 24 h, and 48 h of drug or placebo administration and at discharge. Additional recording was done in the morning (8–10 am) following admission. The primary endpoint was the mean PEFR of each group at these time points; the secondary end point being the need for rescue medications.

Results:

The mean PEFR recordings of the three study groups – placebo, montelukast, and zileuton – respectively, at various time points were as follows: at 6 h (223.25 ± 90.40, 199.00 ± 82.52, 233.75 ± 84.05; P = 0.240); at 12 h (271.00 ± 109.38, 251.50 ± 101.44, 309.50 ± 129.63; P = 0.048); at 24 h (288.25 ± 114.26, 269.00 ± 107.51, 324.50 ± 127.88; P = 0.080); and at 48 h (295.00 ± 114.80, 293.50 ± 113.24, 344.75 ± 119.91; P = 0.015); discharge (305.00 ± 118.56, 305.25 ± 119.51, 361.25 ± 119.70; P = 0.010). The mean PEFR for the three study groups at 8–10 am on the morning following admission was 268.75 ± 111.43, 252.50 ± 99.99, 306.75 ± 114.44; P = 0.047. Total rescue doses needed were 10, 1, and 0, respectively (P = 0.049).

Conclusion:

Zileuton is better than montelukast as an additional drug in acute asthma and results in significant improvement in lung function, and reduction in the need for rescue medications.

Pediatric acute asthma exacerbations: Evaluation and management from emergency department to intensive care unit

OBJECTIVE

The goal of this report is to review available modalities for assessing and managing acute asthma exacerbations in pediatric patients, including some that are not included in current expert panel guidelines. While it is not our purpose to provide a comprehensive review of the National Asthma Education and Prevention Program (NAEPP) guidelines, we review NAEPP-recommended treatments to provide the full range of treatments available for managing exacerbations with an emphasis on the continuum of care between the ER and ICU.

DATA SOURCES

We searched PubMed using the following search terms in different combinations: asthma, children, pediatric, exacerbation, epidemiology, pathophysiology, guidelines, treatment, management, oxygen, albuterol, β2-agonist, anticholinergic, theophylline, corticosteroid, magnesium, heliox, BiPAP, ventilation, mechanical ventilation, non-invasive mechanical ventilation and respiratory failure. We attempted to weigh the evidence using the hierarchy in which meta-analyses of randomized controlled trials (RCTs) provide the strongest evidence, followed by individual RCTs, followed by observational studies. We also reviewed the NAEPP and Global Initiative for Asthma expert panel guidelines.

RESULTS AND CONCLUSIONS

Asthma is the most common chronic disease of childhood, and acute exacerbations are a significant burden to patients and to public health. Optimal assessment and management of exacerbations, including appropriate escalation of interventions, are essential to minimize morbidity and prevent mortality. While inhaled albuterol and systemic corticosteroids are the mainstay of exacerbation management, escalation may include interventions discussed in this review.

Antileukotriene agents for the treatment of lung disease

Leukotrienes (LTs) C4, D4, and E4, collectively termed cysteinyl LTs (cysLTs), are lipid mediators formed by the 5-lipoxygenase (5-LO) pathway of arachidonic acid metabolism. Originally recognized for their potent bronchoconstrictor actions, they were subsequently determined also to promote inflammation, microvascular permeability, and mucus secretion. These actions that are so central to asthma pathophysiology are mediated to a significant extent by ligation of the cysLT receptor 1 (CysLT1). Antagonism of CysLT1 and inhibition of 5-LO have both been shown to have clinical use in the management of asthma, but substantial interindividual heterogeneity is observed in the response to these agents. In this article, we review the biologic actions of LTs, their biosynthetic pathways and cognate receptors, the pharmacology of available anti-LT agents, and the clinical evidence for the use of anti-LT agents as monotherapy and combination therapy in asthma. We also consider heterogeneity of response, the possible roles of cysLT receptors other than CysLT1, the role of another class of LT, LTB4, and the potential role of LTs in lung diseases other than asthma.

Childhood asthma: a guide for pediatric emergency medicine providers

Pediatric asthma is a disease that is managed across outpatient physicians, hospitalists, critical care physicians, and emergency department (ED) physicians. Scoring systems may facilitate a rapid assessment of the child with asthma in the ED. Short-acting beta agonists are still the mainstay of therapy for acute exacerbations along with corticosteroids and ipratropium bromide. ED providers must also know the indications for noninvasive ventilation and intubation. Most patients can be treated and discharged from the ED after acute exacerbation, and should be given a plan for going home that provides educational material and emergency scenarios to help prevent future acute incidents.

Safety and efficacy of montelukast as adjunctive therapy for treatment of asthma in elderly patients

Asthma is a disease of all ages. This assumption has been challenged in the past, because of several cultural and scientific biases. A large body of evidence has accumulated in recent years to confirm that the prevalence of asthma in the most advanced ages is similar to that in younger ages. Asthma in the elderly may show similar functional and clinical characteristics to that occurring in young adults, although the frequent coexistence of comorbid conditions in older patients, together with age-associated changes in the human lung, may lead to more severe forms of the disease. Management of asthma in the elderly follows specific guidelines that apply to all ages, although most behaviors are pure extrapolation of what has been tested in young ages. In fact, age has always represented an exclusion criterion for eligibility to clinical trials. This review focuses specifically on the safety and efficacy of leukotriene modifiers, which represent a valid option in the treatment of allergic asthma, both as an alternative to first-line drugs and as add-on treatment to inhaled corticosteroids. Available studies specifically addressing the role of montelukast in the elderly are scarce; however, leukotriene modifiers have been demonstrated to be safe in this age group, even though cases of acute hepatitis and occurrence of Churg-Strauss syndrome have been described in elderly patients; whether this is associated with age is to be confirmed. Furthermore, leukotriene modifiers provide additional benefit when added to regular maintenance therapy, not differently from young asthmatics. In elderly patients, the simpler route of administration of leukotriene modifiers, compared with the inhaled agents, could represent a more effective strategy in improving the outcomes of asthma therapy, given that unintentional nonadherence with inhalation therapy represents a complex problem that may lead to significant impairment of asthma symptom control.

Novel therapies in asthma: leukotriene antagonists, biologic agents, and beyond

Asthma is one of the most common conditions seen in clinical practice and carries both a significant disease burden in terms of patient morbidity and a high economic burden in both direct and indirect costs. Despite this, it remains a comparatively poorly understood disease, with only modest advances in treatment over the past decade. Corticosteroids remain the cornerstone of therapy. Both patient compliance with medications and physician adherence to evidence-based guidelines are often poor, and a high percentage of patients continue to have inadequately controlled disease even with optimal therapy. Following a contextual overview of the current treatment guidelines, this review focuses on novel asthma therapies, beginning with the introduction of the leukotriene receptor antagonist zafirlukast in the 1990s, continuing through advanced endoscopic therapy and into cytokine-directed biologic agents currently in development. Along with clinically relevant biochemistry and pharmacology, the evidence supporting the place of these therapies in current guidelines will be highlighted along with data comparing these agents with more conventional treatment. A brief discussion of other drugs, such as those developed for unrelated conditions and subsequently examined as potential asthma therapies, is included.

A randomized, double-blind, placebo-controlled trial of oral montelukast in acute asthma exacerbation

Background

Leukotriene receptor antagonists (LTRAs) are well established in the management of outpatient asthma. However, there is very little information as to their role in acute asthma exacerbations. We hypothesized that LTRAs may accelerate lung function recovery when given in an acute exacerbation.

Methods

A randomized, double blind, placebo-controlled trial was conducted at the Aga Khan University Hospital to assess the efficacy of oral montelukast on patients of 16 years of age and above who were hospitalized with acute asthma exacerbation. The patients were given either montelukast or placebo along with standard therapy throughout the hospital stay for acute asthma. Improvements in lung function and duration of hospital stay were monitored.

Results

100 patients were randomized; their mean age was 52 years (SD +/− 18.50). The majority were females (79%) and non-smokers (89%). The mean hospital stay was 3.70 ± 1.93 days with 80% of patients discharged in 3 days. There was no significant difference in clinical symptoms, PEF over the course of hospital stay (p = 0.20 at day 2 and p = 0.47 at day 3) and discharge (p = 0.15), FEV₁ at discharge (p = 0.29) or length of hospital stay (p = 0.90) between the two groups. No serious adverse effects were noted during the course of the study.

Conclusion

Our study suggests that there is no benefit of addition of oral montelukast over conventional treatment in the management of acute asthma attack.

Trial registration

Trial registration number: 375-Med/ERC-04

Asthma in children and adolescents: a comprehensive approach to diagnosis and management

Asthma is a chronic disease that has a significant impact on quality of life and is particularly important in children and adolescents, in part due to the higher incidence of allergies in children. The incidence of asthma has increased dramatically during this time period, with the highest increases in the urban areas of developed countries. It seems that the incidence in developing countries may follow this trend as well. While our knowledge of the pathophysiology of asthma and the available of newer, safer medication have both improved, the mortality of the disease has undergone an overall increase in the past 30 years. Asthma treatment goals in children include decreasing mortality and improving quality of life. Specific treatment goals include but are not limited to decreasing inflammation, improving lung function, decreasing clinical symptoms, reducing hospital stays and emergency department visits, reducing work or school absences, and reducing the need for rescue medications. Non-pharmacological management strategies include allergen avoidance, environmental evaluation for allergens and irritants, patient education, allergy testing, regular monitoring of lung function, and the use of asthma management plans, asthma control tests, peak flow meters, and asthma diaries. Achieving asthma treatment goals reduces direct and indirect costs of asthma and is economically cost-effective. Treatment in children presents unique challenges in diagnosis and management. Challenges in diagnosis include consideration of other diseases such as viral respiratory illnesses or vocal cord dysfunction. Challenges in management include evaluation of the child’s ability to use inhalers and peak flow meters and the management of exercise-induced asthma.

Inhaled and intravenous treatment in acute severe and life-threatening asthma

Management of life-threatening acute severe asthma in children and adults may require anaesthetic and intensive care. The inhaled route for drug delivery is not appropriate when only small respiratory gas volumes are shifted; the i.v. route may be associated with greater side-effects. Magnesium sulphate i.v. has a place in acute asthma management because it is a mild bronchodilator, and has a stabilizing effect on the atria which may attenuate tachycardia occurring after inhaled and i.v. salbutamol. If intubation and ventilation are required, a reduction in bronchoconstriction by any means before and during these procedures should reduce morbidity. This narrative review aims to show strengths and weakness of the evidence, present controversies, and forward opinions of the author. The review contains a practical guide to the setting up, use and efficiency of nebulizers, metered dose inhalers, and spacers (chambers). It also presents a commonsense approach to the management of severe asthmatics in whom delay in bronchodilatation would cause clinical deterioration. When self-inhaled agents have had no effect, i.v. drugs may help avoid intubation and ventilation. The review includes suggestions for the use of inhaled anaesthetics, anaesthetic induction, and brief notes on subsequent ventilation of the lungs.

The efficacy and tolerability of intravenous montelukast in acute asthma exacerbations in Japanese patients

OBJECTIVES

In Japan, the Asthma Prevention and Management Guidelines recommend nebulized β-agonists, IV (intravenous) drip corticosteroids, as well as IV drip aminophylline for acute asthma treatment. However, current treatment for acute asthma provides inadequate benefit for some patients. We evaluated the efficacy and safety of IV montelukast added to standard therapy in Japanese patients with acute asthma exacerbations.

METHODS

This multicenter, randomized, double-blind, parallel-group study compared IV montelukast 7 mg, 14 mg, and placebo in Japanese patients with acute asthma exacerbations (N = 242). Fifteen- to sixty-five-year-old patients with acute asthma were treated with standard care during a screening period that lasted ≤60 minutes. Patients with FEV(1) (forced expiratory volume in 1 second) ≤70 predicted were randomly allocated to one of three treatment groups. The primary end point was the time-weighted average change in FEV(1) from baseline over 60 minutes [ΔFEV(1) (0-60 minutes)] after study drug administration. Secondary end points included the time-weighted average change in FEV(1) over 20, 40, and 120 minutes [ΔFEV(1) (0-T min)].

RESULTS

IV montelukast 7 mg was significantly more effective than placebo for the time-weighted average ΔFEV(1) (0-60 minutes) [least squares (LS) mean 0.09 L vs. 0.01 L; p < .05]. IV montelukast 14 mg was also more effective than placebo (LS mean 0.17 L; p < .001). Similar improvements in time-weighted average [ΔFEV(1) (0-T min)] were seen at all time points (all p < .05). Both doses of IV montelukast demonstrated a significant increase in average ΔFEV(1) compared with placebo within 10 minutes of administration (p < .001 to p < .01). The tolerability of IV montelukast was similar to that of placebo.

CONCLUSION

IV montelukast was significantly more effective than placebo in the improvement of ΔFEV(1) in Japanese patients, suggesting its role as an adjunctive therapy to existing guideline recommendations.

Leukotriene receptor antagonists in addition to usual care for acute asthma in adults and children

BACKGROUND

Acute asthma presentation in the emergency setting frequently leads to hospital admission. Currently available treatment options include corticosteroid therapy, beta(2)-agonists and oxygen. Antileukotriene agents are beneficial in chronic asthma as additional therapy to inhaled steroids. Their value when used orally or intravenously in the acute setting requires evaluation.

OBJECTIVES

To determine if the addition of a leukotriene receptor antagonist (LTRA) produces a beneficial effect in children and adults with acute asthma who are currently receiving inhaled bronchodilators and systemic corticosteroids.

SEARCH METHODS

We searched the Cochrane Airways Group's Specialised Register of trials with predefined terms. Searches are current to February 2012.

SELECTION CRITERIA

We included randomised trials comparing antileukotrienes and standard acute asthma care versus placebo and standard care in people with acute asthma of any age. We considered any dose and method of delivery of the leukotriene agent.

DATA COLLECTION AND ANALYSIS

Two authors independently assessed studies for inclusion in the review and extracted data. We then checked data and resolved disagreements by discussion. We contacted study authors where necessary to provide additional information and data.

MAIN RESULTS

Eight trials, generating 10 treatment-control comparisons, that recruited 1470 adults and 470 children met the entry criteria. These studies were of mixed quality, and there was heterogeneity in the severity of asthma exacerbation.For oral treatment, there was no significant difference in hospital admission between LTRAs and control in three trials on 194 children (risk ratio (RR) 0.86; 95% confidence interval (CI) 0.21 to 3.52). Using a broader composite outcome which measured requirement for additional care there was no significant difference between treatments (RR 0.87; 95% CI 0.60 to 1.28). Results demonstrated some indication of improvement in lung function with a significant difference in forced expiratory volume in one second (FEV(1)) favouring LTRAs in two trials on 641 adults (mean difference (MD) 0.08; 95% CI 0.01 to 0.14). There were insufficient data to assess this outcome in children. The most common adverse event described was headache; however, there was no significant difference between LTRAs and control (RR 0.81; 95% CI 0.22 to 2.99). Due to insufficient numbers, we were unable to conduct a subgroup analysis based on age.The combined results of two trials of intravenous treatment in 772 adults and one trial in 276 children demonstrated a reduction in the risk of hospital admission which was not quite statistically significant (RR 0.78; 95% CI 0.61 to 1.01). There was a statistically significant small difference in FEV(1) in the adult studies (MD 0.12; 95% CI 0.06 to 0.17), but not in the single trial in children (MD 0.01; 95% CI -0.06 to 0.08).

AUTHORS' CONCLUSIONS

Presently, the available evidence does not support routine use of oral LTRAs in acute asthma. Further studies are required to assess whether intravenous treatment can reduce the risk of hospital admission, and what the most appropriate dose regimen is. Additional research is also needed into safety and efficacy of additional doses for those on maintenance therapy, and larger paediatric trials are required to allow subgroup analysis. Prolonged studies would be required to establish other health economic outcomes in admitted patients.

Anti-leukotriene agents compared to inhaled corticosteroids in the management of recurrent and/or chronic asthma in adults and children

BACKGROUND

Anti-leukotrienes (5-lipoxygenase inhibitors and leukotriene receptors antagonists) serve as alternative monotherapy to inhaled corticosteroids (ICS) in the management of recurrent and/or chronic asthma in adults and children.

OBJECTIVES

To determine the safety and efficacy of anti-leukotrienes compared to inhaled corticosteroids as monotherapy in adults and children with asthma and to provide better insight into the influence of patient and treatment characteristics on the magnitude of effects.

SEARCH METHODS

We searched MEDLINE (1966 to Dec 2010), EMBASE (1980 to Dec 2010), CINAHL (1982 to Dec 2010), the Cochrane Airways Group trials register, and the Cochrane Central Register of Controlled Trials (Dec 2010), abstract books, and reference lists of review articles and trials. We contacted colleagues and the international headquarters of anti-leukotrienes producers.

SELECTION CRITERIA

We included randomised trials that compared anti-leukotrienes with inhaled corticosteroids as monotherapy for a minimum period of four weeks in patients with asthma aged two years and older.

DATA COLLECTION AND ANALYSIS

Two review authors independently assessed the methodological quality of trials and extracted data. The primary outcome was the number of patients with at least one exacerbation requiring systemic corticosteroids. Secondary outcomes included patients with at least one exacerbation requiring hospital admission, lung function tests, indices of chronic asthma control, adverse effects, withdrawal rates and biological inflammatory markers.

MAIN RESULTS

Sixty-five trials met the inclusion criteria for this review. Fifty-six trials (19 paediatric trials) contributed data (representing total of 10,005 adults and 3,333 children); 21 trials were of high methodological quality; 44 were published in full-text. All trials pertained to patients with mild or moderate persistent asthma. Trial durations varied from four to 52 weeks. The median dose of inhaled corticosteroids was quite homogeneous at 200 µg/day of microfine hydrofluoroalkane-propelled beclomethasone or equivalent (HFA-BDP eq). Patients treated with anti-leukotrienes were more likely to suffer an exacerbation requiring systemic corticosteroids (N = 6077 participants; risk ratio (RR) 1.51, 95% confidence interval (CI) 1.17, 1.96). For every 28 (95% CI 15 to 82) patients treated with anti-leukotrienes instead of inhaled corticosteroids, there was one additional patient with an exacerbation requiring rescue systemic corticosteroids. The magnitude of effect was significantly greater in patients with moderate compared with those with mild airway obstruction (RR 2.03, 95% CI 1.41, 2.91 versus RR 1.25, 95% CI 0.97, 1.61), but was not significantly influenced by age group (children representing 23% of the weight versus adults), anti-leukotriene used, duration of intervention, methodological quality, and funding source. Significant group differences favouring inhaled corticosteroids were noted in most secondary outcomes including patients with at least one exacerbation requiring hospital admission (N = 2715 participants; RR 3.33; 95% CI 1.02 to 10.94), the change from baseline FEV(1) (N = 7128 participants; mean group difference (MD) 110 mL, 95% CI 140 to 80) as well as other lung function parameters, asthma symptoms, nocturnal awakenings, rescue medication use, symptom-free days, the quality of life, parents' and physicians' satisfaction. Anti-leukotriene therapy was associated with increased risk of withdrawals due to poor asthma control (N = 7669 participants; RR 2.56; 95% CI 2.01 to 3.27). For every thirty one (95% CI 22 to 47) patients treated with anti-leukotrienes instead of inhaled corticosteroids, there was one additional withdrawal due to poor control. Risk of side effects was not significantly different between both groups.

AUTHORS' CONCLUSIONS

As monotherapy, inhaled corticosteroids display superior efficacy to anti-leukotrienes in adults and children with persistent asthma; the superiority is particularly marked in patients with moderate airway obstruction. On the basis of efficacy, the results support the current guidelines' recommendation that inhaled corticosteroids remain the preferred monotherapy. 

Common pediatric respiratory emergencies

Pediatric respiratory illnesses are a huge burden to emergency departments worldwide. This article reviews the latest evidence in the epidemiology, assessment, management, and disposition of children presenting to the emergency department with asthma, croup, bronchiolitis, and pneumonia.

The Pediatric Asthmatic

The incidence of allergies and asthma in the Western world has been increasing over the past 30 years. However, more recent data suggests that over the past 5–10 years, the overall global trends of asthma incidence have begun to stabilize (1). Urbanization and industrialization has contributed to the increase in developed countries, but the reasons for this are still unclear. Asthma is estimated to be responsible for 1 in every 250 deaths worldwide. Many of these deaths are preventable, and specific issues have been identified that may contribute to this high mortality rate. Factors that contribute to high ­mortality and morbidity include slow access to care and medications, inadequate environmental control of allergens and irritants, dietary changes, genetic variations, cultural barriers, lack of education amongst patients and providers, insufficient resources, and improper use of health care dollars.

Asthma diagnosis and management

Asthma is a chronic inflammatory airway disease that is commonly seen in the emergency department (ED). This article provides an evidence-based review of diagnosis and management of asthma. Early recognition of asthma exacerbations and initiation of treatment are essential. Treatment is dictated by the severity of the exacerbation. Treatment involves bronchodilators and corticosteroids. Other treatment modalities including magnesium, heliox, and noninvasive ventilator support are discussed. Safe disposition from the ED can be considered after stabilization of the exacerbation, response to treatment and attaining peak flow measures.

Management of severe acute asthma in the emergency department

PURPOSE OF REVIEW

Asthma is one of the most common chronic diseases in most developed countries and control may be elusive. Deterioration in asthma control is common when patients are exposed to airway irritants, viruses, and/or when adherence to chronic anti-inflammatory medications is suboptimal. Acute asthma exacerbations are common, important reasons for presentations to emergency departments, and severe cases may result in hospitalization. Important knowledge gaps exist in what is known and what care is delivered at the bedside.

RECENT FINDINGS

The literature in asthma is rapidly expanding and recent advances in the care are important to summarize. Systematic reviews, especially high-quality syntheses performed using Cochrane methods, provide the best evidence for busy clinicians to remain current. Management of asthma is based on early recognition of severe disease with aggressive therapy using multimodal interventions that focus on both bronchoconstriction and inflammatory mechanisms.

SUMMARY

Treatment of severe acute asthma can effectively and safely reduce hospitalizations, airway interventions, and even death. Using the approach outlined herein will enable clinicians to assist patients to rapidly regain asthma control, return to normal activities, and improve their quality of life in the follow-up period.

Analytic review: management of life-threatening asthma in adults

Asthma remains a troubling health problem despite the availability of effective treatment. A small but significant number of asthmatics experience life-threatening attacks culminating in intensive care unit admission. Standard treatment includes high dose systemic corticosteroids and inhaled bronchodilators. Patients with especially severe attacks may develop respiratory failure and need endotracheal intubation and mechanical ventilation. Severe airway obstruction may lead to dynamic hyperinflation and the possibility of hemodynamic collapse and barotrauma. Fortunately, most intubated asthmatics survive if physicians adhere to key management principles intended to avoid or minimize hyperinflation. The purpose of this review is to discuss the pathogenesis of life-threatening asthma and to provide practical guidance to promote rationale, safe, and effective management.

Randomized trial of zileuton for treatment of COPD exacerbations requiring hospitalization

RATIONALE

Leukotrienes have been implicated in the pathogenesis of acute exacerbations of COPD, but leukotriene modifiers have not been studied as a possible therapy for exacerbations.

OBJECTIVE

We sought to test the safety and efficacy of adding oral zileuton (a 5-lipoxygenase inhibitor) to usual treatment for acute exacerbations of COPD requiring hospitalization.

METHODS

Randomized double-blind, placebo-controlled, parallel group study of zileuton 600 mg orally, 4 times daily versus placebo for 14 days starting within 12 hours of hospital admission for COPD exacerbation. Primary outcome measure was hospital length of stay; secondary outcomes included treatment failure and biomarkers of leukotriene production.

MAIN FINDINGS

Sixty subjects were randomized to zileuton and 59 to placebo (the study was stopped short of enrollment goals because of slow recruitment). There was no difference in hospital length of stay (3.75 +/- 2.19 vs. 3.86 +/- 3.06 days for zileuton vs. placebo, p = 0.39) or treatment failure (23% vs. 27% for zileuton vs. placebo, p = 0.63) despite a decline in urinary LTE(4) levels in the zileuton-treated group as compared to placebo at 24 hours (change in natural log-transformed ng/mg creatinine -1.38 +/- 1.19 vs. 0.14 +/- 1.51, p < 0.0001) and 72 hours (-1.32 +/- 2.08 vs. 0.26 +/- 1.93, p<0.006). Adverse events were similar in both groups.

PRINCIPAL CONCLUSIONS

While oral zileuton during COPD exacerbations that require hospital admission is safe and reduces urinary LTE(4) levels, we found no evidence suggesting that this intervention shortened hospital stay, with the limitation that our sample size may have been insufficient to detect a modest but potentially meaningful clinical improvement.

Pharmacologic approaches to life-threatening asthma

Following a peak in asthma mortality in the late 1980s and early 1990s, we have been fortunate to see a substantial decrease in asthma deaths in recent years. Although most asthma deaths occur outside the hospital, near-fatal events are commonplace, with anywhere from 2-20% of patients with acute asthma admitted to intensive care, and 2-4% intubated for respiratory failure. Standard therapies for acute severe and near-fatal asthma include administration of systemic corticosteroids, and frequent or continuous inhaled beta agonists. Controversy remains regarding the optimal therapy of those who fail to respond to these initial treatments, those who remain at risk of acute respiratory failure, and patients requiring mechanical ventilation. There remain significant gaps in our knowledge regarding relative benefits of intravenous versus oral corticosteroids, intermittent versus continuous beta agonists, and the role of various adjunctive treatments including intravenous magnesium, systemic beta agonists, aminophylline, and helium-oxygen mixtures. Using models and radiolabeled aerosols, there is a greater understanding regarding effective administration of inhaled beta-agonists in ventilated patients. There is limited available evidence for treatment of near-fatal asthma, a fact reflected by the significant variability in asthma critical care practice. Much of the data guiding treatment in this setting has been generalized from studies of acute asthma in the ED and from general populations of hospitalized patients with acute asthma. This review will focus on pharmacologic approaches to life-threatening asthma by reviewing current guideline recommendations, reviewing the scientific basis of the guidelines, and highlighting gaps in our knowledge in treatment of refractory acute or near-fatal asthma.

Leukotrienes and airway inflammation

BACKGROUND

Asthma is a common chronic inflammatory disease of the airways characterized by airway obstruction and hyperresponsiveness. Leukotrienes (LTs) are lipid mediators that contribute to many aspects of asthma pathogenesis. As the LT pathway is relatively steroid-resistant, its blockade by alternative strategies is a desirable component of asthma management. Cysteinyl LT (cysLT) receptor 1 antagonists (LTRAs) have been utilized worldwide for more than 10years, and while their efficacy in asthma is well accepted, their limitations are also evident.

SCOPE OF REVIEW

In this review, we summarize the biological effects of LTs in asthma, review recent advances in LT receptors, and consider possible new therapeutic targets in the LT pathway that offer the potential to achieve better control of asthma in the future.

MAJOR CONCLUSIONS

CysLTs play pathogenetic roles in many aspects of asthma, and blockade of cysLT receptor 1 by currently available LTRAs is certainly beneficial in disease management. On the other hand, the limitations of LTRAs are also apparent. Recent studies have revealed new receptors for cysLTs other than classical cysLT receptors 1 and 2, as well as the potential importance of LTB(4) in asthma.

GENERAL SIGNIFICANCE

Recent findings provide clues to new approaches for targeting the LT pathway that may overcome the current limitations of LTRAs and achieve superior control of asthma. This article is part of a Special Issue entitled: Biochemistry of Asthma.

Leukotriene modifiers for asthma treatment

Leukotrienes (LTs), including cysteinyl LTs (CysLTs) and LTB(4) , are potent lipid mediators that have a role in the pathophysiology of asthma. At least two receptor subtypes for CysLTs, CysLT(1) and CysLT(2) , have been identified. The activation of the CysLT(1) receptor is responsible for most of the pathophysiological effects of CysLTs in asthma, including increased airway smooth muscle activity, microvascular permeability, and airway mucus secretion. LTB(4) might have a role in severe asthma, asthma exacerbations, and the development of airway hyperresponsiveness. CysLT(1) receptor antagonists can be given orally as monotherapy in patients with mild persistent asthma, but these drugs are generally less effective than inhaled glucocorticoids. Combination of CysLT(1) receptor antagonists and inhaled glucocorticoids in patients with more severe asthma may improve asthma control and enable the dose of inhaled glucocorticoids to be reduced while maintaining similar efficacy. The identification of subgroups of asthmatic patients who respond to CysLT(1) receptor antagonists is relevant for asthma management as the response to these drugs is variable. CysLT(1) receptor antagonists have a potential anti-remodelling effect that might be important for preventing or reversing airway structural changes in patients with asthma. This review discusses the role of LTs in asthma and the role of LT modifiers in asthma treatment.

Intravenous montelukast in asthma exacerbations: could it help?

Asthma is a chronic inflammatory disease leading to recurrent episodes of airflow limitation. It has a significant impact both on individuals and society. Pharmacological agents prescribed for asthma management belong to various therapeutic drug classes and are classically administered via the inhalatory route. Recently, leukotriene receptor antagonists have become more widely available and have been shown to produce a variable degree of bronchodilation. Oral montelukast increases the control over the disease in both children and adults and can reduce the dose of inhalatory steroids required in patients with moderate-to-severe and exercise-induced asthma. Recently, intravenous montelukast was shown to improve the airflow in patients with stable asthma more rapidly. However, the role of this formulation in the treatment of acute asthma is unknown. The current study examines the effect of intravenous montelukast in asthma exacerbations.

Role of Leukotrienes and Leukotriene Modifiers in Asthma

Leukotrienes (LTs), including cysteinyl LTs (CysLTs) and LTB₄, are potent lipid mediators that are pivotal in the pathophysiology of asthma phenotypes. At least two receptor subtypes for CysLTs - CysLT1 and CysLT₂ - have been identified. Most of the pathophysiological effects of CysLTs in asthma, including increased airway smooth muscle activity, microvascular permeability and airway mucus secretion, are mediated by the activation of the CysLT1 receptor. LTB₄ may have a role in the development of airway hyperresponsiveness, severe asthma and asthma exacerbations. Although generally less effective than inhaled glucocorticoids, CysLT₁ receptor antagonists can be given orally as monotherapy in patients with persistent mild asthma. In patients with more severe asthma, CysLT₁ receptor antagonists can be combined with inhaled glucocorticoids. This therapeutic strategy improves asthma control and enables the dose of inhaled glucocorticoids to be reduced, while maintaining similar efficacy. The identification of subgroups of patients with asthma who respond to CysLT₁ receptor antagonists is relevant for asthma management, as the response to these drugs is variable. The potential anti-remodeling effect of CysLT₁ receptor antagonists might be important for preventing or reversing airway structural changes in patients with asthma. This review discusses the role of LTs in asthma and the therapeutic implications of the pharmacological modulation of the LT pathway for asthma.

A randomized, placebo-controlled study of intravenous montelukast in children with acute asthma

BACKGROUND

Up to 30% of patients require hospitalization for acute asthma despite standard therapy in the emergency department. In adults, intravenous montelukast added to standard therapy significantly improved forced expiratory volume in 1 second (FEV1) and reduced hospital admissions compared with standard therapy alone.

OBJECTIVE

To evaluate the efficacy of intravenous montelukast added to standard therapy in children with acute asthma.

METHODS

This was a randomized, double-blind, placebo-controlled, multicenter study of children aged 6 to 14 years conducted from August 25, 2005 to March 17, 2008. Patients with an FEV1 of 75% or less of the predicted value after up to 120 minutes of standard therapy (e.g., oxygen, albuterol, inhaled anticholinergics, and systemic oral corticosteroids) were randomized to intravenous montelukast, 5.25 mg (n=145), or placebo (n=131) added to standard therapy. The primary end point was the time-weighted average change in FEV1 during 60 minutes (deltaFEV1[0-60 min]). Secondary end points included the percentage of patients in whom treatment failed (patients who required hospitalization or for whom a decision to discharge was not reached within 2 hours after drug administration) and the change from baseline in modified pulmonary index score after 60 minutes of treatment.

RESULTS

Montelukast was not significantly more effective than placebo for deltaFEV1[0-60 min] when added to standard therapy (0.08 vs. 0.07 L; least squares mean, 0.01; 95% confidence interval, -0.06 to 0.08; P = .78). No significant differences were found in the percentages of patients in whom treatment failed or the modified pulmonary index score after 60 minutes. Both treatments were well tolerated.

CONCLUSIONS

In this study of children with acute asthma, intravenous montelukast was not significantly better than placebo in improving FEV1, symptoms, or overall hospital course.

Acute additive effect of montelukast and beclomethasone on AMP induced bronchoconstriction

Bronchial hyperresponsiveness to 5-adenosine mono-phosphate (AMP) is a marker of airway inflammation. Inhaled corticosteroids and antileukotrienes are used as anti-inflammatory drugs for the treatment of asthma. To find out if these two drugs exert their protection in an additive fashion, we compared the effects of acute treatment with inhaled beclomethasone (BDP) and montelukast (ML), alone or in combination, on methacholine and AMP induced bronchoconstriction. 15 asthmatic patients undertook methacholine and AMP challenges at baseline and after receiving ML or BDP, alone or in combination, in a randomized, double-blind, double-dummy placebo-controlled, crossover design. BDP pretreatment significantly increased the AMP PC(20) value (68.34+/-15.9mg/mL) as compared to placebo (22.87+/-5.7mg/mL). Combined treatment, BDP plus ML, afforded a further significant increase of AMP PC(20) (154.57+/-55.0mg/mL) as compared to each single treatment. The significant protection exerted by combined treatment as compared to each single active treatment was also demonstrated by the change of AMP PC(20) doubling dose as compared to placebo and each single active treatment. Our findings suggest that these two agents exert their acute additive protection against AMP induced bronchoconstriction acting on distinct inflammatory pathways and their combined use might provide greater protection against inflammatory response elicited by AMP than either drug alone.

Acute severe asthma: new approaches to assessment and treatment

The precise definition of a severe asthmatic exacerbation is an issue that presents difficulties. The term 'status asthmaticus' relates severity to outcome and has been used to define a severe asthmatic exacerbation that does not respond to and/or perilously delays the repetitive or continuous administration of short-acting inhaled beta(2)-adrenergic receptor agonists (SABA) in the emergency setting. However, a number of limitations exist concerning the quantification of unresponsiveness. Therefore, the term 'acute severe asthma' is widely used, relating severity mostly to a combination of the presenting signs and symptoms and the severity of the cardiorespiratory abnormalities observed, although it is well known that presentation does not foretell outcome. In an acute severe asthma episode, close observation plus aggressive administration of bronchodilators (SABAs plus ipratropium bromide via a nebulizer driven by oxygen) and oral or intravenous corticosteroids are necessary to arrest the progression to severe hypercapnic respiratory failure leading to a decrease in consciousness that requires intensive care unit (ICU) admission and, eventually, ventilatory support. Adjunctive therapies (intravenous magnesium sulfate and/or others) should be considered in order to avoid intubation. Management after admission to the hospital ward because of an incomplete response is similar. The decision to intubate is essentially based on clinical judgement. Although cardiac or respiratory arrest represents an absolute indication for intubation, the usual picture is that of a conscious patient struggling to breathe. Factors associated with the increased likelihood of intubation include exhaustion and fatigue despite maximal therapy, deteriorating mental status, refractory hypoxaemia, increasing hypercapnia, haemodynamic instability and impending coma or apnoea. To intubate, sedation is indicated in order to improve comfort, safety and patient-ventilator synchrony, while at the same time decrease oxygen consumption and carbon dioxide production. Benzodiazepines can be safely used for sedation of the asthmatic patient, but time to awakening after discontinuation is prolonged and difficult to predict. The most common alternative is propofol, which is attractive in patients with sudden-onset (near-fatal) asthma who may be eligible for extubation within a few hours, because it can be titrated rapidly to a deep sedation level and has rapid reversal after discontinuation; in addition, it possesses bronchodilatory properties. The addition of an opioid (fentanyl or remifentanil) administered by continuous infusion to benzodiazepines or propofol is often desirable in order to provide amnesia, sedation, analgesia and respiratory drive suppression. Acute severe asthma is characterized by severe pulmonary hyperinflation due to marked limitation of the expiratory flow. Therefore, the main objective of the initial ventilator management is 2-fold: to ensure adequate gas exchange and to prevent further hyperinflation and ventilator-associated lung injury. This may require hypoventilation of the patient and higher arterial carbon dioxide (PaCO(2)) levels and a more acidic pH. This does not apply to asthmatic patients intubated for cardiac or respiratory arrest. In this setting the post-anoxic brain oedema might demand more careful management of PaCO(2) levels to prevent further elevation of intracranial pressure and subsequent complications. Monitoring lung mechanics is of paramount importance for the safe ventilation of patients with status asthmaticus. The first line of specific pharmacological therapy in ventilated asthmatic patients remains bronchodilation with a SABA, typically salbutamol (albuterol). Administration techniques include nebulizers or metered-dose inhalers with spacers. Systemic corticosteroids are critical components of therapy and should be administered to all ventilated patients, although the dose of systemic corticosteroids in mechanically ventilated asthmatic patients remains controversial. Anticholinergics, inhaled corticosteroids, leukotriene receptor antagonists and methylxanthines offer little benefit, and clinical data favouring their use are lacking. In conclusion, expertise, perseverance, judicious decisions and practice of evidence-based medicine are of paramount importance for successful outcomes for patients with acute severe asthma.

Pharmacology of PF-4191834, a novel, selective non-redox 5-lipoxygenase inhibitor effective in inflammation and pain

5-Lipoxygenase (LOX) is an important arachidonic acid-metabolizing enzyme producing leukotrienes and other proinflammatory lipid mediators with potent pathophysiological functions in asthma and other inflammatory diseases. 4-(3-(4-(1-Methyl-1H-pyrazol-5-yl)phenylthio)phenyl)-tetrahydro-2H-pyran-4-carboxamide (PF-4191834) is a novel, selective non-redox 5-lipoxygenase inhibitor effective in inflammation and pain. In vitro and in vivo assays were developed for the evaluation of a novel 5-LOX inhibitor using conditions of maximal enzyme activity. PF-4191834 exhibits good potency in enzyme- and cell-based assays, as well as in a rat model of acute inflammation. Enzyme assay results indicate that PF-4191834 is a potent 5-LOX inhibitor, with an IC(50) = 229 +/- 20 nM. Furthermore, it demonstrated approximately 300-fold selectivity for 5-LOX over 12-LOX and 15-LOX and shows no activity toward the cyclooxygenase enzymes. In addition, PF-4191834 inhibits 5-LOX in human blood cells, with an IC(80) = 370 +/- 20 nM. This inhibitory concentration correlates well with plasma exposures needed for in vivo efficacy in inflammation in models of inflammatory pain. The combination of potency in cells and in vivo, together with a sustained in vivo effect, provides PF-4191834 with an overall pharmacodynamic improvement consistent with once a day dosing.

A randomized placebo-controlled study of intravenous montelukast for the treatment of acute asthma

BACKGROUND

Current treatments for acute asthma provide inadequate benefit for some patients. Intravenous montelukast may complement existent therapies.

OBJECTIVE

To evaluate efficacy of intravenous montelukast as adjunctive therapy for acute asthma.

METHODS

A total of 583 adults with acute asthma were treated with standard care during a < or = 60-minute screening period. Patients with FEV(1) < or =50% predicted were randomly allocated to intravenous montelukast 7 mg (n = 291) or placebo (n = 292) in addition to standard care. This double-blind treatment period lasted until a decision for discharge, hospital admission, or discontinuation from the study. The primary efficacy endpoint was the time-weighted average change in FEV(1) during 60 minutes after drug administration. Secondary endpoints included the time-weighted average change in FEV(1) at various intervals (10-120 minutes) and percentage of patients with treatment failure (defined as hospitalization or lack of decision to discharge by 3 hours postadministration).

RESULTS

Montelukast significantly increased FEV(1) at 60 minutes postdose; the difference between change from baseline for placebo (least-squares mean of 0.22 L; 95% CI, 0.17, 0.27) and montelukast (0.32 L; 95% CI, 0.27, 0.37) was 0.10 L (95% CI, 0.04, 0.16). Similar improvements in FEV(1)-related variables were seen at all time points (all P <.05). Although treatment failure did not differ between groups (OR 0.92; 95% CI, 0.63, 1.34), a prespecified subgroup analysis suggests likely benefit for intravenous montelukast at US sites.

CONCLUSION

Intravenous montelukast added to standard care in adults with acute asthma produced significant relief of airway obstruction throughout the 2 hours after administration, with an onset of action as early as 10 minutes.

Review article: management of acute severe and near-fatal asthma

Despite a decline in the Australian overall asthma mortality, near-fatal/critical asthma continues to be a significant management issue for emergency physicians and intensivists. Near-fatal asthma is a unique subtype of asthma, with a variety of clinical presentations, requiring rapid and aggressive intervention. The pharmacological and non-pharmacological management of near-fatal asthma remains very complex. The present review discusses recent advances and evidence for current available strategies targeting this time critical emergency.

Can montelukast shorten prednisolone therapy in children with mild to moderate acute asthma? A randomized controlled trial

OBJECTIVE

To examine whether outpatient post-stabilization therapy with montelukast produces more treatment failures than prednisolone.

STUDY DESIGN

In this randomized, double-blind, double-dummy non-inferiority trial, 130 children 2 to 17 years of age with mild to moderate acute asthma stabilized with prednisolone in the emergency department received 5 daily treatments with either prednisolone or montelukast after discharge. The primary outcome was treatment failure within 8 days (ie, an asthma-related unscheduled visit, hospitalization, or additional systemic corticosteroids).

RESULTS

The rates of treatment failure were 7.9% in the prednisolone group and 22.4% in the montelukast group (95% CI, 26.5%-2.4%). Treatment was more likely to fail in younger patients (odds ratio, 4.9). In the montelukast group, more patients received additional pharmacotherapy than in patients receiving prednisolone (23.9% versus 9.5%, P = .03). The differences in the daily salbutamol treatments, asymptomatic days, and changes in the Pediatric Respiratory Assessment Measure score were not significant (P = .85, .75, and .26, respectively).

CONCLUSION

Montelukast does not represent an adequate alternative to corticosteroids after outpatient stabilization in mild to moderate acute asthma. This population should receive oral corticosteroids after discharge.

An umbrella review: corticosteroid therapy for adults with acute asthma

The objective of this "umbrella" review is to synthesize the evidence and provide clinicians a single report that summarizes the state of knowledge regarding the use of corticosteroids in adults with acute asthma. Systematic reviews in the Cochrane Library and additional clinical trials published in English from 1966 to 2007 in MEDLINE, EMBASE, CINAHL, and Cochrane CENTRAL, and references from bibliographies of pertinent articles were reviewed. Results indicate that the evidence base is frequently limited to small, single-center studies. Findings suggest that therapy with systemic corticosteroids accelerates the resolution of acute asthma and reduces the risk of relapse. There is no evidence that corticosteroid doses greater than standard doses (prednisone 50-100 mg equivalent) are beneficial. Oral and intravenous corticosteroids, as well as intramuscular and oral corticosteroid regimens, seem to be similarly effective. A nontapered 5- to 10-day course of corticosteroid therapy seems to be sufficient for most discharged patients. Combinations of oral and inhaled corticosteroids on emergency department/hospital discharge might minimize the risk of relapse.

P2Y6 receptors require an intact cysteinyl leukotriene synthetic and signaling system to induce survival and activation of mast cells

Cysteinyl leukotrienes (cys-LTs) induce inflammatory responses through type 1 (CysLT1R) and type 2 (CysLT2R) cys-LT receptors and activate mast cells in vitro. We previously demonstrated that cys-LTs cross-desensitized IL-4-primed primary human mast cells (hMCs) to stimulation with the nucleotide uridine diphosphate (UDP). We now report that hMCs, mouse bone marrow-derived mast cells (mBMMCs), and the human MC line LAD2 all express UDP-selective P2Y6 receptors that cooperate with CysLT1R to promote cell survival and chemokine generation by a pathway involving reciprocal ligand-mediated cross-talk. Leukotriene (LT) D4, the most potent CysLT1R ligand, and UDP both induced phosphorylation of ERK and prolonged the survival of cytokine-starved hMCs and mBMMCs. ERK activation and cytoprotection in response to either ligand were attenuated by treatment of the cells with a selective P2Y6 receptor antagonist (MRS2578), which did not interfere with signaling through recombinant CysLT1R. Surprisingly, both UDP and LTD4-mediated ERK activation and cytoprotection were absent in mBMMCs lacking CysLT1R and the biosynthetic enzyme LTC4 synthase, implying a requirement for a cys-LT-mediated autocrine loop. In IL-4-primed LAD2 cells, LTD4 induced the generation of MIP-1beta, a response blocked by short hairpin RNA-mediated knockdown of CysLT1R or P2Y6 receptors, but not of CysLT2R. Thus, CysLT1R and P2Y6 receptors, which are coexpressed on many cell types of innate immunity, reciprocally amplify one another's function in mast cells through endogenous ligands.

Asthma in childhood

Management decisions for pediatric asthma (in patients younger than 12 years of age) based on extrapolation from available evidence in adolescents and adults (age 12 years and older) is common but rarely appropriate. This article addresses the disparity in response between the two age groups, presents the available pediatric evidence, and highlights the important areas in which further research is required. Evidence-based recommendations for acute and interval management of pediatric asthma are provided.

The effect of asthma therapeutics on signalling and transcriptional regulation of airway smooth muscle function

SCOPE OF THE REVIEW

Our knowledge of the multifunctional nature of airway smooth muscle (ASM) has expanded rapidly in the last decade, but the underlying molecular mechanisms and how current therapies for obstructive airway diseases, such as asthma and chronic obstructive pulmonary disease (COPD), affect these are still being elucidated. Our current knowledge has built on the pharmacology of human ASM contraction and relaxation established prior to that and which is reviewed in detail elsewhere in this issue. The advent of methods to isolate and culture ASM cells, especially human ASM cells, has made it possible to study how they may contribute to airway remodelling through their synthetic, proliferative, and migratory capacities. Now the underlying molecular mechanisms of ASM growth factor secretion, extracellular matrix (ECM) production, proliferation and migration, as well as contraction and relaxation, are being determined. A complex network of signalling pathways leading to gene transcription in ASM cells permits this functional plasticity in healthy and diseased airways. This review is an overview of the effects of current therapies, and some of those in development, on key signalling pathways and transcription factors involved in these ASM functions.