Formoterol via Turbuhaler® gave better protection than terbutaline against repeated exercise challenge for up to 12 hours in children and adolescents

Abstract

We aimed to compare the protective effect of single doses of 4·5 and 9 μg of formoterol fumarate (F), 0·5 mg terbutaline sulphate (T) and placebo (P), all via Turbuhaler®, against exercise-induced bronchoconstriction (EIB) in children. Twenty-seven asthmatic children, showing a fall of ≥20% in FEV1 after a standardized exercise challenge test (ECT) combined with cold air (- 10°C) inhalation, were randomized in this cross-over, double-blind study. They had a mean age of 12·6 years (range 8-17 years), mean baseline FEV1 90% (73·9-105·6%) of predicted normal value. Seventeen children used inhaled glucocorticosteroids (120-750 μg day-1). ECTs were performed 15 min and 4, 8, and 12 h after drug administration. F significantly reduced the fall in FEV1 after ECT to 5·4% (15 min), 5·2% (4 h), 8·2% (8 h) and 9·3% (12 h) after 4·5 μg, and 2·5%, 3·0%, 5·0% and 5·4% after 9 μg, compared with a fall of 18·4%, 15·7%, 15·6% and 16·5% in FEV1 after P. The fall after T was 3·3%, 11·6%, 14·4% and 19·1% after 15 min, 4, 8 and 12 h respectively. The difference between F and T was statistically significant from 4 h and onward (P-value for all comparisons <0·05). Children using a single dose of either formoterol Turbuhaler 4·5 or 9 μg had significantly better bronchoprotection against repeated exercise challenge up to 12 h compared with placebo and from 4 h onward compared with terbutaline Turbuhaler® 0·5 mg.