Evaluation of Duovent in the prevention of exercise-induced asthma

Exercise-induced asthma (EIA) is a frequent symptom in asthmatic patients. The study of drugs which inhibit EIA is very important because EIA seriously limits the life of the patients. In addition, this study could allow further insights to be gained into the pathogenesis of the phenomenon. The aim of the present study is to evaluate the duration of the protective effect of fenoterol alone or in combination with ipratropium bromide administered 5 h before exercise. For this purpose we studied 12 asthmatic patients (7 males and 5 females, mean age 23, range 7-41 years) with EIA, in clinical and functional stable state. Respiratory function parameters were measured before and 5 h after the administration of fenoterol 400 or 200 micrograms, or fenoterol 200 micrograms plus ipratropium bromide 80 micrograms (Duovent), or placebo in randomized order. Then, such parameters were measured at 5, 15, 30, and 60 min after exercise, which consisted of free running up and down the stairs. The results show that, at 5 h after the administration of each drug, the protective action against EIA is only partial. However, the intense bronchodilation afforded by the 'active' drugs, and particularly by 400 micrograms of fenoterol, keeps post-exertional respiratory parameters above the baseline values.