What is New with the β2-Agonists: Issues in the Management of Asthma

Abstract

OBJECTIVE: To review the more recent literature addressing the issue of whether β2-agonists can worsen asthma and/or increase the risk of severe exacerbations and death from asthma. DATA SOURCES: PubMed was searched (2001–December 2004), along with the Food and Drug Administration and Cochrane Library Web sites. In addition, the bibliographies of recent reviews of the subject were assessed. STUDY SELECTION AND DATA EXTRACTION: Randomized clinical trials, retrospective and prospective cohort studies, and meta-analyses published in the past 3 years were reviewed. Studies assessing the potential for β2-agonists to worsen outcomes in asthma as well as long-term studies assessing asthma outcomes that included an arm with regular administration of short- or long-acting inhaled β2-agonists (LABAs) were selected. Worsening asthma was defined as a decline in lung function, an increase in bronchial hyperresponsiveness, exacerbations, or death. Studies older than 3 years selected from the bibliographies of the primary articles that addressed background perspective were also included where appropriate. DATA SYNTHESIS: The studies fell into 3 primary categories with some overlap: those assessing toxicity of the S-enantiomer of albuterol, those evaluating the risk of specific genotypes regarding worsening asthma, and those assessing asthma outcomes with LABA therapy. CONCLUSIONS: The current data on the use of β2-agonists continue to support the national and international guidelines for the treatment of asthma. That is, short-acting inhaled β2-agonists should only be used as needed for symptoms and prevention of exercise-induced bronchospasm, and LABAs should only be used regularly as adjunctive therapy with inhaled corticosteroids in patients whose asthma is not controlled with low to medium doses of the inhaled corticosteroid.