The therapeutic ratio of R-albuterol is comparable with that of RS-albuterol in asthmatic patients

Management of the acute exacerbation of asthma

All patients with asthma are at risk of having asthma exacerbations characterized by worsening symptoms, airflow obstruction, and an increased requirement for rescue bronchodilators. The goals of managing an asthma exacerbation are prompt recognition and rapid reversal of airflow obstruction to avert relapses and future episodes. Short-acting beta-agonists, oxygen, and corticosteroids form the basis of management of acute asthma exacerbation, but a role is emerging for anticholinergics and newer agents such as levalbuterol and formoterol. Initiation or intensification of long-term controller therapy, treatment of comorbid conditions, avoidance of likely triggers, and timely follow-up care prevent setbacks. Acceptance of current treatment guidelines by physicians and adherence to the recommended clinical regimens by patients are essential for effective management of asthma. The physician should strive to establish a constructive relationship with the patient by addressing the patient's concerns, reaching agreement on the goals of therapy, and developing a written action plan for patient self-management.

Retrospective comparison of nebulized levalbuterol and albuterol for adverse events in patients with acute airflow obstruction

The objective of this study was to retrospectively compare the mean change in heart rate (HR) of patients with acute airflow obstruction treated with nebulized levalbuterol vs. albuterol. The study was conducted at the Akron General Medical Center, a 537-bed adult tertiary care teaching and research medical center. The participants were patients (> or = 18 years old) presenting to the emergency department with acute airflow obstruction. This was a retrospective chart review. Treatment groups received either levalbuterol (0.63 mg) or albuterol (2.5 mg). Respiratory care notes record HRs before and after nebulization of levalbuterol or albuterol. Primary analysis was conducted on days 1 and 3 of therapy to determine whether there is a difference between levalbuterol and albuterol with regard to mean change in HR with each treatment. In the primary analysis data, 35 subjects in each treatment group were compared. The mean age (+/- SD) was 65 +/- 16.4 and 68 +/- 16.5 for levalbuterol and albuterol, respectively. On day 1 of therapy, the difference in the mean change in HR with albuterol compared with levalbuterol was 1.0 bpm (95% CI, -1.6 to 3.7). On day 3, a statistically significant difference occurred in mean change in HR between treatment groups at 2.7 bpm (95% CI, 0.02 to 5.4). An increase in HR of 2.7 bpm by albuterol compared with levalbuterol on day 3 of therapy was the only significant finding among the analyses. However, this finding did not demonstrate dangerous elevations in HR following treatment with albuterol. Even the upper end of the confidence interval range at 5.4 bpm does not support a clinically significant difference in tachycardia with the pure isomer compared with the racemic mixture during acute airway obstruction.

Levalbuterol: pharmacologic properties and use in the treatment of pediatric and adult asthma

LEARNING OBJECTIVES

To review the rationale supporting the use of levalbuterol [(R)-albuterol] for the treatment of pediatric and adult asthma.

DATA SOURCES

Peer-reviewed articles, selected abstracts from studies presented at recent professional meetings, and the Xopenex [levalbuterol, (R)-albuterol; Sepracor, Marlborough, MA] Summary Basis of Approval and package insert.

STUDY SELECTION

Institutional review board-approved clinical study protocols.

RESULTS

Levalbuterol is a single isomer beta2-agonist that differs from racemic albuterol by elimination of (S)-albuterol. Levalbuterol is an effective bronchodilator whose primary mechanism of action is unimpeded by (S)-albuterol. Thus, when compared with racemic albuterol, clinically comparable bronchodilation can be achieved with doses that substantially lessen beta-mediated side effects. In chronic or acute treatment of asthma, this favorable therapeutic profile cannot apparently be duplicated by increasing or decreasing the dose of racemic albuterol or by the addition of anticholinergic agents such as ipratropium bromide.

CONCLUSIONS

Levalbuterol seems to provide efficacy and safety advantages in pediatric and adult patients suffering from asthma. Its use may afford a cost benefit as well. More clinical studies are required to extend these observations for use in the treatment of other pulmonary diseases in both adults and children and to determine levalbuterol's impact on long-term therapy of respiratory diseases.

Clinical advances in adult asthma

From October 2001 through September 2002, reports of clinical research on asthma in adults focused on the epidemiology of asthma, the investigation of pharmacologic and immunologic therapy in the context of new national guidelines, and discussions of medical economics. Epidemiologic findings include the observation that overall mortality has declined and hospitalizations have remained constant in the United States since 1995, although these rates are at least twice as high in Blacks. Socially and economically disadvantaged groups receive poorer health care for asthma. Young children who have fewer than 5 episodes of wheezing in conjunction with respiratory infections generally have a good prognosis and do not have compromised lung function as adults. Pharmacologic reports and the National Asthma Education and Prevention Program Update recommend low- to medium-dose inhaled steroids combined with a long-acting beta-agonist as the preferred therapy for moderate persistent asthma. The use of chlorofluorocarbon-free medications for asthma is increasing. Medications comprise the largest cost category for asthma.

Single-isomer levalbuterol: a review of the acute data

Levalbuterol, the pure (R)-isomer of racemic albuterol, is a new therapeutic option for patients with asthma. Racemic albuterol comprises a 50:50 mixture of (R)- and (S)-albuterol, with (R)-albuterol conferring all of the bronchodilator effects of the racemate. Numerous preclinical and in vitro studies have indicated that (S)-albuterol is not an inert isomer, but may have proinflammatory effects. Results from clinical trials in adults and children with asthma have demonstrated that 0.63 mg levalbuterol provides effective bronchodilation with lower b-mediated side effects compared with 2.5 mg racemic albuterol. In the emergency department, levalbuterol provided greater bronchodilation and significantly reduced hospital admissions compared with racemic albuterol. Recent studies have supported that levalbuterol use in acute settings may reduce the cost of asthma treatment by decreasing the total treatments and subsequent respiratory therapy resources. Levalbuterol provides heath care professionals with a safe, effective, and potentially cost-saving alternative to racemic albuterol for the treatment of patients with asthma.

Managing outpatient asthma exacerbations

Asthma is a chronic inflammatory disease that renders individuals prone to acute exacerbations. Several allergic and nonallergic triggers can incite an asthma exacerbation. The goals of managing an asthma exacerbation are prompt recognition, rapid reversal of airflow obstruction, prevention of relapses, and forestalling future episodes. A written asthma home-management plan is essential to minimize the severity of exacerbations. Short-acting b-agonists, oxygen, and corticosteroids are fundamental to early intervention in acute asthma exacerbation. Anticholinergics and magnesium sulfate can help nonresponders. Newer agents such as levalbuterol and long-acting b-agonists might be future additions to our armamentarium of drugs to treat acute exacerbations. Initiation or intensification of long-term controller therapy, treatment of co-morbid conditions, and avoidance of possible triggers along with prompt follow-up can help prevent relapses. Listening to patient preferences and concerns to enhance adherence and regular follow-up care can help prevent future episodes.

6. Asthma

The increasing incidence and prevalence of asthma in many parts of the world continue to make it a global health concern. The heterogeneous nature of the clinical manifestations and therapeutic responses of asthma in both adult and pediatric patients indicate that it may be more of a syndrome rather than a specific disease entity. Numerous triggering factors including viral infections, allergen and irritant exposure, and exercise, among others, complicate both the acute and chronic treatment of asthma. Therapeutic intervention has focused on the appreciation that airway obstruction in asthma is composed of both bronchial smooth muscle spasm and variable degrees of airway inflammation characterized by edema, mucus secretion, and the influx of a variety of inflammatory cells. The presence of only partial reversibility of airflow obstruction in some patients indicates that structural remodeling of the airways may also occur over time. Choosing appropriate medications depends on the disease severity (intermittent, mild persistent, moderate persistent, severe persistent), extent of reversibility, both acutely and chronically, patterns of disease activity (exacerbations related to viruses, allergens, exercise, etc), and the age of onset (infancy, childhood, adulthood).

Atopic diseases of childhood

The atopic diseases of childhood consist of the triad of asthma, allergic rhinitis, and atopic dermatitis. All share a common pathogenesis, being mediated by IgE, and are frequently present together in the same individual and family. These disorders and their comorbidities comprise a large component of general pediatric practice and their incidence in developed countries has been increasing over the past few decades. They are a leading reason for clinic and emergency room visits, as well as hospital admissions. They have the potential to interfere with education, physical activity, socialization, and self-esteem. Fortunately, we now have a reasonable armamentarium of maintenance medications available to help control these disorders and improve the quality of life for children suffering from them. In addition, early diagnosis and aggressive management of these disorders seem to offer the possibility of altering their natural history. As such, developing a sensible approach to the diagnosis and treatment of these disorders in an outpatient setting is essential. In this review, I summarize the most current literature and provide a framework for effectively diagnosing and managing these disorders.

The evaluation and management of acute, severe asthma

This article provides a systematic approach to the patient with acute, severe asthma. After a brief, focused evaluation prompt treatment with inhaled beta 2-agonists and systemic corticosteroids remains the cornerstone of treatment. Ipratropium bromide is now recognized as a useful addition for both adult and pediatric populations, whereas consideration of intravenous MgSO4 and theophylline is warranted for refractory patients. Ongoing evaluation of antileukotriene agents offers a possibility of these agents as alternative bronchodilators. Further research with a number of potential acute asthma agents will further expand treatment options for rapid symptomatic airway improvement and prevention of progressing airway obstruction, hospitalization, and potential respiratory failure.

Management of acute, severe asthma in children

OBJECTIVE

To briefly present the current options available for the treatment of acute, severe asthma in children, with a special focus on emergency department and inpatient treatment, and to describe newer therapies that may aid treatment in the future.

DATA SOURCES AND STUDY SELECTION

A MEDLINE search (1966-May 2001) of the English-language literature pertaining to drug therapy of acute asthma was performed. Key word searches included acute asthma, albuterol, ipratropium, corticosteroids, magnesium, and theophylline. Additional articles from these sources and published national guidelines were identified. Relevant studies pertaining to current therapy of acute asthma in pediatric patients were selected; if there were minimal pediatric data, adult data were included.

DATA SYNTHESIS

Asthma is a chronic, inflammatory disorder of the airways. Acute exacerbations can occur and are challenging to manage. Albuterol, ipratropium, and systemic corticosteroids have been shown to be effective in acute asthma exacerbations. Because some patients do not respond to maximal therapy, older therapies such as magnesium and theophylline are being reevaluated. Theophylline may have some therapeutic effect, but given its toxicity profile, it is unclear whether it offers any advantage over maximal beta(2)-agonist therapy. There are only minimal published data evaluating the use of magnesium in pediatrics, and most are small trials or case reports. Newer therapies such as ventilation strategies with heliox and intravenous leukotriene modifiers currently being evaluated may or may not prove to be beneficial in the future.

CONCLUSIONS

beta(2)-agonists, ipratropium, and corticosteroids remain the most useful therapeutic agents for acute asthma exacerbations in pediatric patients. However, these agents are not ideal in all patients and, given the existing questions regarding safety and/or efficacy of available alternatives, more effective options are needed.

Beta-adrenoceptor agonists and asthma--100 years of development

Inhaled beta(2)-adrenoceptor agonists are by far the most effective and safe bronchodilators currently available. They have not been surpassed by any other bronchodilating principle. The way to this position has been long and started with the first successful treatment of acute, severe asthma with s.c. injections of adrenaline 100 years ago. Over the years, synthetic congeners of adrenaline have been produced and tested for their pharmacological properties. During the first decades, little attention was given airway smooth muscle. The discovery of isoprenaline in 1940 was the first major step towards selective bronchodilation. This compound became a key tool for the classification of adrenoceptors into alpha and beta. Salbutamol and terbutaline were the first to show a significant attenuation of the cardiostimulant effect and confirmed the subdivision of beta-adrenoceptors into beta(1) and beta(2). Much effort was made to eliminate the next dose-limiting side effect, skeletal muscle tremor but in vain. Prolonged duration of action was achieved in three ways: with bambuterol, an orally active carbamate ester prodrug of terbutaline, salmeterol, an inhaled beta(2)-adrenoceptor agonist emerging from a purposeful research project, and formoterol which was found, accidentally, to have a long duration of action when inhaled. Throughout the 20th century, beta-adrenoceptor agonists have been developed and marketed as racemates. The pharmacological activity usually resides in the (R)-enantiomer. Despite claims for the opposite, there is so far no compelling evidence that the presence of the less active (S)-enantiomer is of any harm to the patient. One hundred years of experience of structural modifications of adrenaline has shown that the possibilities to modify the properties of this endogenous prototype appear to be unlimited.