Short-acting beta(2)-agonists are the mainstay of
therapy for acute
bronchospasm associated with
asthma and
chronic obstructive pulmonary disease, whereas long-acting beta(2)-agonists are used in maintaining disease control in these respiratory disorders. This review describes and compares the pharmacology of the beta(2)-agonists and explains how these differences translate into differences in efficacy and beta(2)-adrenergic-mediated adverse effects. Questions commonly asked by clinicians regarding the efficacy and safety of short- and long-acting beta(2)-agonists include issues about cardiovascular effects, tolerance to their
bronchodilator and bronchoprotective effects, blunting of
albuterol response by long-acting beta(2)-agonists, potential masking of worsening
asthma control, and the role of long-acting beta(2)-agonists as adjunctive
therapy with inhaled
corticosteroids in maintaining
asthma control. Pharmacogenetics may play a role in determining which patients may be at risk for a reduced response to a beta(2)-agonist. The continued use of racemic
albuterol, which contains a mixture of R-
albuterol and S-
albuterol, has been questioned because of data from preclinical and clinical studies suggesting that S-
albuterol causes proinflammatory effects and may increase
bronchial hyperreactivity. The preclinical and clinical effects of these two stereoisomers are reviewed. Data describing the efficacy and safety of
levalbuterol (R-
albuterol) and racemic
albuterol are presented.