Beta-Adrenergic Agonists for Acute, Severe Asthma

Abstract

OBJECTIVE: To critically review the use of beta-adrenergic agonists in acute, severe asthma with particular focus on aerosol administration. DATA SOURCES: English language articles published since 1971 on the use of beta-agonists for acute asthma. Studies were identified from bibliographies of book chapters, review articles, and other research articles. STUDY SELECTION: All studies (21 total) comparing systemic with inhaled beta-agonists were reviewed, regardless of their design or outcome. Selected studies highlighting specific aspects of beta-agonist use in acute asthma such as beta-agonists versus other bronchodilators, aerosol delivery, and intravenous beta-agonists were also reviewed. DATA EXTRACTION: Performed subjectively by the authors with specific aspects of quality discussed within the body of the article. DATA SYNTHESIS: The beta-agonists provide superior bronchodilation in acute severe asthma compared with either the methylxanthines and/or anticholinergics. The majority of studies found aerosolized beta-agonists to be either as effective as or more effective than parenteral beta-agonists and to produce fewer adverse cardiovascular effects. Studies showing preference for parenteral therapy have either been of poor design or used low doses of an aerosolized beta-agonist. Based on studies of aerosol delivery, there is no advantage of jet nebulization over metered-dose inhalers; however, other aspects, including ease of administration, favor nebulization as the delivery method of choice. The articles recommending intravenous beta-agonists consist of a series of uncontrolled cases. CONCLUSIONS: Aerosolized selective beta2-agonists are the bronchodilator treatments of choice for acute, severe asthma. Attention to the details of dosing and delivery are required for optimal results. The final dose and dosing interval are determined by the patient's response. Intravenous beta-agonists are hazardous and cannot be recommended.