The rational use of beta(2)-agonists in the management of asthma: Maintenance, rescue, and emergency

beta(2)-adrenoceptor agonists (beta(2)-agonists) are the most effective kno wn bronchodilators. In conjunction with antiinflammatory agents, they play an important role in every step of asthma therapy. Rational choice among th e many available agents must be based on pharmacologic principles and clini cal data. For maintenance therapy designed to optimize lung function and pr event symptoms, a long-acting inhaled beta(2)-agonist of low intrinsic effi cacy offers advantages that are most closely approximated by salmeterol. Fo r rescue therapy in order to relieve acute symptoms, an inhaled beta(2)-ago nist with a rapid onset of action, intermediate duration, and intermediate efficacy is optimal, These features are present in various formulations of albuterol, terbutaline, pirbuterol, and bitolterol. For emergency treatment of acute asthma that does not respond to standard rescue therapy, administ ration of rescue beta(2)-agonists at higher doses and increased frequency g enerally suffices. The full agonists isoproterenol and epinephrine may be r equired to avert intubation in some patients, however.