Zafirlukast treatment for acute asthma: evaluation in a randomized, double-blind, multicenter trial

Zafirlukast inhibits the growth of lung adenocarcinoma via inhibiting TMEM16A channel activity

Lung cancer has the highest mortality among cancers worldwide due to its high incidence and lack of the effective cures. We have previously demonstrated that the membrane ion channel TMEM16A is a potential drug target for the treatment of lung adenocarcinoma and have identified a pocket of inhibitor binding that provides the basis for screening promising new inhibitors. However, conventional drug discovery strategies are lengthy and costly, and the unpredictable side effects lead to a high failure rate in drug development. Therefore, finding new therapeutic directions for already marketed drugs may be a feasible strategy to obtain safe and effective therapeutic drugs. Here, we screened a library of over 1400 Food and Drug Administration-approved drugs through virtual screening and activity testing. We identified a drug candidate, Zafirlukast (ZAF), clinically approved for the treatment of asthma, that could inhibit the TMEM16A channel in a concentration-dependent manner. Molecular dynamics simulations and site-directed mutagenesis experiments showed that ZAF can bind to S387/N533/R535 in the nonselective inhibitor binding pocket, thereby blocking the channel pore. Furthermore, we demonstrate ZAF can target TMEM16A channel to inhibit the proliferation and migration of lung adenocarcinoma LA795 cells. In vivo experiments showed that ZAF can significantly inhibit lung adenocarcinoma tumor growth in mice. Taken together, we identified ZAF as a novel TMEM16A channel inhibitor with excellent anticancer activity, and as such, it represents a promising candidate for future preclinical and clinical studies.

Factors associated with relapse in adult patients discharged from the emergency department following acute asthma: a systematic review

A significant proportion of patients discharged from the emergency department (ED) with asthma exacerbations will relapse within 4 weeks. This systematic review summarises the evidence regarding relapses and factors associated with relapse in adult patients discharged from EDs after being treated for acute asthma. Following a registered protocol, comprehensive literature searches were conducted. Studies tracking outcomes for adults after ED management and discharge were included if they involved adjusted analyses. Methodological quality was assessed using the Newcastle–Ottawa Scale (NOS) and the Risk of Bias (RoB) Tool. Results were summarised using medians and IQRs or mean and SD, as appropriate. 178 articles underwent full-text review and 10 studies, of various methodologies, involving 32 923 patients were included. The majority of the studies were of high quality according to NOS and RoB Tool. Relapse proportions were 8±3%, 12±4% and 14±6% at 1, 2 and 4 weeks, respectively. Female sex was the most commonly reported and statistically significant factor associated with an increased risk of relapse within 4 weeks of ED discharge for acute asthma. Other factors significantly associated with relapse were past healthcare usage and previous inhaled corticosteroids (ICS) usage. A median of 17% of patients who are discharged from the ED will relapse within the first 4 weeks. Factors such as female sex, past healthcare usage and ICS use at presentation were commonly and significantly associated with relapse occurrence. Identifying patients with these features could provide clinicians with guidance during their ED discharge decision-making.

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.

Evaluating the role of leukotriene-modifying drugs in asthma management: Are their benefits 'losing in translation'?

Leukotrienes (LTs) initiate a cascade of reactions that cause bronchoconstriction and inflammation in asthma. LT-modifying drugs have been proved very effective to reduce inflammation and associated exacerbation however despite some illustrious clinical trials the usage of these drugs remains overlooked because the evidence to support their utility in asthma management has been mixed and varied between studies. Although, there are plenty of evidences which suggest that the leukotriene-modifying drugs provide consistent improvement even after just the first oral dose and reduce asthma exacerbations, the beneficial effect of these drugs has remained sparse and widely debated. And these beneficial effects are often overlooked because most of the clinical studies include a mixed population of asthmatics who do not respond to LT-modifiers equally. Therefore, in the present era of personalized medicine, it is important to properly stratify the patients and non-invasive measurements of biomarkers may warrant the possibility to characterize biological/pathological pathway to direct treatment to those who will benefit from it. Endotyping based on individual's leukotriene levels should probably ascertain a subgroup of patients that would clearly benefit from the treatment even though the trial fails to show overall significance. In this article, we have methodically evaluated contemporary literature describing the efficacy of LT-modifying drugs in the management of asthma and highlighted the importance of phenotyping the asthmatics for better treatment outcomes.

Cysteinyl leukotriene receptor-1 antagonists as modulators of innate immune cell function

Cysteinyl leukotrienes (cysLTs) are produced predominantly by cells of the innate immune system, especially basophils, eosinophils, mast cells, and monocytes/macrophages. Notwithstanding potent bronchoconstrictor activity, cysLTs are also proinflammatory consequent to their autocrine and paracrine interactions with G-protein-coupled receptors expressed not only on the aforementioned cell types, but also on Th2 lymphocytes, as well as structural cells, and to a lesser extent neutrophils and CD8⁺ cells. Recognition of the involvement of cysLTs in the immunopathogenesis of various types of acute and chronic inflammatory disorders, especially bronchial asthma, prompted the development of selective cysLT receptor-1 (cysLTR1) antagonists, specifically montelukast, pranlukast, and zafirlukast. More recently these agents have also been reported to possess secondary anti-inflammatory activities, distinct from cysLTR1 antagonism, which appear to be particularly effective in targeting neutrophils and monocytes/macrophages. Underlying mechanisms include interference with cyclic nucleotide phosphodiesterases, 5′-lipoxygenase, and the proinflammatory transcription factor, nuclear factor kappa B. These and other secondary anti-inflammatory mechanisms of the commonly used cysLTR1 antagonists are the major focus of the current review, which also includes a comparison of the anti-inflammatory effects of montelukast, pranlukast, and zafirlukast on human neutrophils in vitro, as well as an overview of both the current clinical applications of these agents and potential future applications based on preclinical and early clinical studies.

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 controller delay and recurrence risk after an emergency department visit or hospitalization

BACKGROUND

Patients who have asthma-related emergency department (ED) visits or hospitalizations are at risk for recurrent exacerbation events. Our objectives were to assess whether receiving a controller medication at discharge affects risk of recurrence and whether delaying controller initiation alters this risk.

METHODS

Asthma patients with an ED visit or inpatient (IP) stay who received a controller dispensing within 6 months were identified from healthcare claims. Cox proportional hazards of the time to first recurrence of an asthma-related ED or IP visit in the 6-month period following the initial event were constructed, with time following discharge without controller medication as the primary predictor.

RESULTS

A total of 6139 patients met inclusion criteria, 78% with an ED visit and 22% with an IP visit; 15% had a recurrence within 6 months. The adjusted hazard ratio (HR) associated with not having controller medication at discharge was 1.79 (95% confidence interval [CI], 1.42-2.25). The controller-by-time interaction was significant (P<0.001), with hazard rising as time-to-controller initiation increased. Delaying initiation by 1 day approximately tripled the risk (HR 2.95; 95%CI 1.48-5.88). Sensitivity analyses, including accounting for controller fills prior to the index event, did not substantially alter these results.

CONCLUSIONS

This observational study shows that the risk of a recurrent asthma-related ED visit or IP stay increased as the time to initiate a controller increased. Our findings support the importance of early controller initiation following an asthma-related ED or IP visit in reducing risk of recurrence.

Effects of a short course of pranlukast combined with systemic corticosteroid on acute asthma exacerbation induced by upper respiratory tract infection

BACKGROUND

Upper respiratory tract infections (URIs) represent the most frequent cause of acute asthma exacerbation. Systemic corticosteroid (CS) is presently recommended for URI-induced asthma exacerbation, although it might inhibit cellular immunity against respiratory virus infection.

OBJECTIVES

To determine the effects of adding a short course (2 weeks) of a leukotriene receptor antagonist (LTRA) to systemic CS on URI-induced acute asthma exacerbation.

METHODS

Twenty-three adult asthmatics (mean age, 42.8 ± 9.8 y; Male:Female, 10:13) with URI-induced acute asthma exacerbation confirmed by a questionnaire and physical findings were randomly assigned to receive either oral prednisolone (PSL) alone or oral PSL plus the LTRA pranlukast (PRL) for 2 weeks (PSL + PRL). The cumulative doses of PSL and the amount of time required to clear asthma-related symptoms were determined. Levels of respiratory syncytial virus (RSV) RNA and influenza viral (IV) antigen in nasopharyngeal swabs were also determined.

RESULTS

Adding PRL significantly reduced the cumulative dose of PSL and tended to reduce the time required to clear asthma-related symptoms. Either RSV or IV was detected in about one-third of the patients.

CONCLUSION

The combination of an LTRA and CS might be more useful than CS alone for treating URI-induced acute exacerbation of asthma and reducing the cumulative CS dose.

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.

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.

Acute lung failure

Lung failure is the most common organ failure seen in the intensive care unit. The pathogenesis of acute respiratory failure (ARF) can be classified as (1) neuromuscular in origin, (2) secondary to acute and chronic obstructive airway diseases, (3) alveolar processes such as cardiogenic and noncardiogenic pulmonary edema and pneumonia, and (4) vascular diseases such as acute or chronic pulmonary embolism. This article reviews the more common causes of ARF from each group, including the pathological mechanisms and the principles of critical care management, focusing on the supportive, specific, and adjunctive therapies for each condition.

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.

Management of status asthmaticus in children

Asthma is a common chronic inflammatory disorder of the airways characterized by recurrent wheezing, breathlessness, and coughing. Acute exacerbations of asthma can be life-threatening; annual worldwide estimated mortality is 250,000 and most of these deaths are preventable. While most of the acute exacerbations can be managed successfully in the emergency room, few children have severe exacerbations requiring intensive care. Mainstay of treatment for status asthmaticus are inhaled β2 agonist and anticholinergic agents, oxygen along with corticosteroids. Children who do not respond well to initial treatment require parenteral β2 agonist and magnesium. Rarely, sick children need parenteral aminophylline infusion and mechanical ventilation. Guidelines for diagnosis, treatment, ventilator management and supportive care for status asthmaticus in children are discussed in the protocol.

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.

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.

[Critical analysis of asthma guidelines: are they really evidence-based?]

Recent years have seen a growing reliance on "evidence-based" guidelines or consensus statements, in which rigorous, explicit methods are used to translate the complex findings of scientific research into operational recommendations for medical care. Various factors can affect the validity of the conclusions they express, however. The purpose of this review was to compare the levels of evidence supporting treatments for acute asthma in adults according to 3 of the most important guidelines. It seems that even though these guidelines are based on an approach that is more or less rigorous, there are considerable gaps and inconsistencies that compromise their validity. Our main sources of information should therefore be those that apply the best research designs, namely randomized controlled trials or meta-analyses of such trials with consistent results and a low probability of bias.

Relapse after emergency department discharge for acute asthma

OBJECTIVES

The objectives were to determine patient and treatment-response factors associated with relapse after emergency department (ED) treatment for acute asthma.

METHODS

Subjects aged 18-55 years who were treated for acute asthma in 20 Canadian EDs prospectively underwent a structured ED interview and telephone contact 2 weeks later.

RESULTS

Of 695 enrolled patients, 604 (86.9%) were discharged from the ED; follow-up was available in 529 (87.5%); 63% were female and the median age was 29 years. Most patients were discharged on oral (70.8%) and inhaled (60.1%) corticosteroids (CS); 2-week treatment adherences were 93.3 and 80.9%, respectively. Relapse occurred in 9.2% at 1 week (95% confidence interval [CI] = 7.1% to 12.0%) and 13.9% (95% CI = 11% to 17%) at 2 weeks. In multivariable modeling, factors associated with relapse were ethnicity (risk ratio [RR] white = 0.66; 95% CI = 0.52 to 0.83); female gender (RR = 1.57; 95% CI = 1.14 to 2.09); any ED visits in the past 2 years (RR = 1.47; 95% CI = 1.18 to 1.80); ever admitted for asthma treatment (RR = 1.83; 95% CI = 1.09 to 2.84); use of combined inhaled CS plus long-acting beta(2)-agonists (RR = 1.39; 95% CI = 1.07 to 1.78) and of oral CS (RR = 1.35; 95% CI = 1.12 to 1.59) at the time of ED presentation.

CONCLUSIONS

Ethnicity (white), female gender, prior ED visits and admissions for asthma, and recent treatments (especially oral CS) were associated with asthma relapse, which remains relatively common. Future research is required to target this high-risk group.

Near-fatal asthma: recognition and management

PURPOSE OF REVIEW

Near-fatal asthma continues to be a significant problem despite the decline in overall asthma mortality. The purpose of this review is to discuss recent advances in our understanding of the pathophysiology, diagnosis and treatment of near-fatal asthma.

RECENT FINDINGS

Two distinctive phenotypes of near-fatal asthma have been identified: one with eosinophilic inflammation associated with a gradual onset and a slow response to therapy and a second phenotype with neutrophilic inflammation that has a rapid onset and rapid response to therapy. Patients who develop sudden-onset near-fatal asthma seem to have massive allergen exposure and emotional distress. In stable condition, near-fatal asthma frequently cannot be distinguished from mild asthma. Diminished perception of dyspnea plays a relevant role in treatment delay, near-fatal events, and death in patients with severe asthma. Reduced compliance with anti-inflammatory therapy and ingestion of medications or drugs (heroin, cocaine) have been associated with fatal or near-fatal asthma.

SUMMARY

Near-fatal asthma is a subtype of asthma with unique risk factors and variable presentation that requires early recognition and aggressive intervention.

Antileukotrienes as adjunctive therapy in acute asthma

The leukotriene receptor antagonists (LTRAs) are a comparatively new class of asthma drugs that exhibit both bronchodilator and anti-inflammatory properties. There is a substantial body of evidence for their benefit in the management of chronic asthma in both adults and children, and particularly in specific types of asthma such as exercise-induced and aspirin-sensitive asthma. Despite best practice using current treatment guidelines for the management of acute asthma, a significant proportion of patients require continued treatment and are unable to be discharged from the emergency department; many require a short course of oral corticosteroids. The relatively rapid onset of action of LTRAs after oral administration and their additive effect to beta(2)-adrenoceptor agonists led to the hypothesis that they might be of benefit in acute asthma. This review examines the available evidence for the effect of LTRAs in acute asthma. Although the evidence is limited, it suggests that treatment with LTRAs provides additional bronchodilator effect to nebulised and inhaled beta(2)-adrenoceptor agonists. Short-term therapy with LTRAs results in fewer treatment failures and readmissions for patients with acute asthma, and less need for additional therapies such as nebulisers and corticosteroids.

FEV1 performance among patients with acute asthma: results from a multicenter clinical trial

OBJECTIVE

To determine the ability of patients seen for acute asthma exacerbations in the emergency department (ED) to perform good-quality FEV(1) measurements.

METHODS

Investigators from 20 EDs were trained to perform spirometry testing as part of a clinical trial that included standardized equipment with special software-directed prompts. Spirometry was done on ED arrival and 30 min, 1 h, 2 h, and 4 h later, and during follow-up outpatient visits.

MEASUREMENTS

Study performance criteria differed from American Thoracic Society (ATS) guidelines because of the population acuity and severity of illness as follows: ability to obtain acceptable FEV(1) measures (defined as two or more efforts with forced expiratory times >/= 2 s and time to peak flow < 120 ms or back-extrapolated volume < 5% of the FVC) and reproducibility criteria (two highest acceptable FEV(1) values within 10% of each other).

RESULTS

Of the 620 patients (age range, 12 to 65 years), > 90% met study acceptability criteria on ED arrival and 74% met study reproducibility criteria. Mean initial FEV(1) was 38% of predicted. Spirometry quality improved over time; by 1 h, 90% of patients met study acceptability and reproducibility criteria. Patients with severe airway obstruction (FEV(1) < 25% of predicted) were initially less likely to meet quality goals, but this improved with time. The site was also an independent predictor of quality.

CONCLUSION

When staff are well trained and prompt feedback regarding adequacy of efforts is given, modified ATS performance goals for FEV(1) tests can be met from most acutely ill adolescent and adult asthmatics, even within the first hour of evaluation and treatment for an asthma exacerbation.

Improved outcomes from acute severe asthma in Australian intensive care units (1996 2003)

BACKGROUND

There is limited information on changes in the epidemiology and outcome of patients with asthma admitted to intensive care units (ICUs) in the last decade. A database sampling intensive care activity in hospitals throughout Australia offers the opportunity to examine these changes.

METHODS

The Australian and New Zealand Intensive Care Society Adult Patient Database was examined for all patients with asthma admitted to ICUs from 1996 to 2003. Demographic, physiological and outcome information was obtained and analysed from 22 hospitals which had submitted data continuously over this period.

RESULTS

ICU admissions with the primary diagnosis of asthma represented 1899 (1.5%) of 126 906 admissions during the 8-year period. 36.1% received mechanical ventilation during the first 24 h. The overall incidence of admission to ICU fell from 1.9% in 1996 to 1.1% in 2003 (p<0.001). Overall hospital mortality was 3.2%. There was a significant decline in mortality from a peak of 4.7% in 1997 to 1.1% in 2003 (p = 0.014). This was despite increasing severity of illness (as evidenced by an increasing predicted risk of death derived from the APACHE II score) over the 8-year period (p = 0.002).

CONCLUSIONS

There has been a significant decline in the incidence of asthma requiring ICU admission between 1996 and 2003 among units sampled by the Australian and New Zealand Intensive Care Society Adult Patient Database. The mortality of these patients has also decreased over time and is lower than reported in other studies.

Treatment strategies for reducing asthma-related emergency department visits

Acute asthma exacerbations reflect inadequate long-term disease control. Treatment to control acute asthma exacerbations includes: 1) rapid reversal of airflow obstruction with bronchodilators and systemic corticosteroids and reversing hypoxemia with oxygen in the emergency department (ED); 2) preventing early relapse by prescribing beta(2) agonists and oral corticosteroids at discharge and ensuring patients have an adequate supply of their other asthma medications; and 3) preventing future asthma exacerbations and ED visits through effective treatment in primary care. This article discusses each treatment and reviews the role of emergency physicians in treating patients to reverse airflow obstruction and prevent early relapse, future exacerbations, and ED visits by communicating the need for additional asthma control to patients' primary care physicians.

Acute asthma exacerbations: phenotypes and management

Acute asthma presentations account for 2 million emergency department visits annually in the United States. The causes for these presentations range from undertreated or unrecognized disease, to exacerbations of stable disease usually caused by recent exposure to triggers of exacerbations, to severe disease states unresponsive to conventional therapy. Indeed, many of these patients often exhibit both acute and chronic markers of severe asthma. The recognition of these phenotypes of acute asthma can enhance the management of these patients in acute and emergency settings. This article describes these potential phenotypes, reviews current therapies, and addresses the challenges of variability of therapeutic response in acute asthma.

Oral montelukast treatment of preschool-aged children with acute asthma

BACKGROUND

Increased amounts of cysteinyl leukotrienes have been demonstrated in urine samples from asthmatic patients, particularly during exacerbations of asthma. Although the use of leukotriene receptor antagonists has been recommended in the treatment of chronic asthma, no guidelines are available regarding their use in the treatment of acute asthma.

OBJECTIVE

To investigate the safety and effectiveness of a 4-mg tablet of oral montelukast in addition to short-acting beta2-agonist bronchodilator as the initial treatment in mild to moderate asthma exacerbations in children between 2 and 5 years old.

METHODS

Fifty-one patients who were experiencing mild to moderate asthma exacerbation were included in a randomized, double-blind, placebo-controlled, parallel-group study. Each patient received either a 4-mg tablet of montelukast or placebo in addition to inhaled salbutamol and were followed up for 4 hours. The pulmonary index score, respiratory rate, and pulse were determined at baseline and throughout 4 hours after administration.

RESULTS

Compared with placebo, the pulmonary index scores and respiratory rates were significantly lower in the montelukast group starting at 90 minutes (P = .01). This difference persisted at 120, 180, and 240 minutes of the study (P = .008, P = .02, and P = .048, respectively). At the end of the first hour of treatment, oral steroid need was 20.8% and 38.5% in patients randomized to the montelukast and placebo groups, respectively (P = .22). Hospitalization rates were not different between the 2 treatment groups.

CONCLUSION

A single 4-mg tablet of montelukast had the potential to provide additive clinical benefit in mild to moderate acute asthma in preschool-aged children when administered concomitantly with short-acting beta2-agonist bronchodilators as the initial treatment.

Dyspnea and asthma

PURPOSE OF REVIEW

Dyspnea--the perception of respiratory discomfort--is a primary symptom of asthma. This review examines possible ways to link mechanisms, measurement and treatment that will increase our understanding of this condition.

RECENT FINDINGS

Functional neuroimaging methods have proven to be powerful tools that serve as advanced models of sensor motor brain function. Studies examining functional neuroimaging methods have revealed activation of distinct brain areas associated with increased dyspnea. Pulmonary hyperinflation has been proposed to influence the perception of dyspnea. The association of hyperinflation with minor levels of bronchoconstriction reflects the partition of the sensory effect of airway narrowing per se from that of the attendant elastic loading of the inspiratory muscles. There is evidence to suggest, however, that hyperinflation does not play an important role in the pathogenesis of exercise dyspnea as it does during induced bronchoconstriction. Decreased levels of perception of airway obstruction may be a risk factor associated with life-threatening asthma. A poor perceiver may be vulnerable to further hypoxia-induced suppression of respiratory sensation. Monitoring the response to bronchodilator therapy with formoterol and salbutamol in patients with acute or chronic asthma has resulted in significantly faster improvement in dyspnea, within 2 min.

SUMMARY

Regardless of the factors involved, much variability in dyspnea scores remains unexplained. Quantitative and qualitative assessment of the perception of dyspnea, symptom measurement and quality of life complement physiological measurements and contribute to our understanding of dyspnea in asthma.

Acute asthma during pregnancy

In addition to preventing maternal and fetal hypoxia, the goals of treating acute asthma exacerbation during pregnancy mirror those in the nongravid patient: rapid reversal of airflow obstruction with aerosolized bronchodilators,reduction of likelihood of recurrence by the addition of corticosteroids, and ongoing assessment of mother and fetus. Disposition decisions are multifaceted and must take into account the health and well-being of the pregnant patient and that of her fetus. Discharge planning includes prescription of scheduled 3-2 agonist treatments until symptoms resolve, intensification of daily treatment as needed, prescriptions for systemic and ICSs, as well provision of patient education, a personalized action plan, and close follow-up.

The linkage between Churg-Strauss syndrome and leukotriene receptor antagonists: fact or fiction?

Epidemiologic evidence has shown that the worldwide prevalence of asthma is increasing. The leukotriene receptor antagonists (LTRAs) represent a new class of therapy for asthma. They have been developed in the last decade and play a pivotal steroid-sparing role in treating the inflammatory component of asthma. Consequently, reports of Churg-Strauss syndrome (CSS), a rare form of systemic vasculitis, have been recognized as a potential side effect in individuals with moderate to severe asthma on LTRA therapy. The serious nature of this disorder is worthy of prompt recognition by clinicians and aggressive therapy to avoid the subsequent longstanding effects of vasculitis. To validate the postulated linkage between the LTRAs and CSS, this review comprehensively evaluates reported cases in the literature and supports a pathophysiological relationship between the LTRAs and the development of CSS.