Inhaled Terbutaline Administered via a Spacer Fully Prevents Exercise-Induced Asthma in Young Asthmatic Subjects: A Double-Blind,Randomized,Placebo-Controlled Study

The effects of inhaled terbutaline, a β₂-adrenergic agonist, administered via a 750-ml spacer device were studied in young asthmatic subjects with exercise-induced asthma. A double-blind, randomized, placebo-controlled study of the effects of inhaled 0.5 mg terbutaline and placebo was conducted in 10 asthmatic children (age range 6–16 years) with documented exercise-induced asthma. Forced expiratory volume in 1 s (FEV₁) was measured at baseline, 15 min after inhaling terbutaline or placebo, and at intervals up to 60 min after exercising. Subjects exercised using a cycle ergometer for 5 min at a submaximal, constant work-load while breathing dry air at room temperature. Terbutaline induced bronchodilation at rest in all subject and fully prevented exercise-induced asthma in nine out of the 10 subjects; the exercise-induced fall in FEV₁ was markedly reduced in the remaining subject. It is concluded that exercise-induced asthma can be inhibited by pretreatment with inhaled terbutaline, administered via a spacer, in a majority of young asthmatics.