Bronchodilators: new drugs and controversies.

After complete abstinence, regular use of short-acting beta 2-agonists results in an increase in early and late asthmatic (allergen) response, exercise-induced bronchoconstriction, and nonspecific airways responsiveness (methacholine). Regular use of long-acting beta 2-agonists also results in increased nonspecific airways responsiveness (methacholine) with or without concomitant inhaled corticosteroids and attenuates the response to escalating doses of inhaled short-acting beta 2-agonists such as might be used in an acute exacerbation. In spite of these findings, symptom control and bronchodilation are improved more with the addition of salmeterol than with a doubling of inhaled corticosteroid dose. Selective cyclic nucleotide phosphodiesterase inhibitors show promise in expanding the bronchodilator and anti-inflammatory effects of theophylline.