SALMETEROL IN EXERCISE-INDUCED BRONCHOCONSTRICTION IN ASTHMATIC-CHILDREN - COMPARISON OF 2 DOSES

Since the optimal dose of salmeterol in asthmatic children has not yet been clearly defined, we compared the efficacy and duration of the pr otective effect of two doses of salmeterol (25 and 50 mu g) against ex ercise-induced bronchoconstriction. Twelve children (aged 7-14 yrs) wi th asthma were studied in a double-blind, cross-over, placebo-controll ed design. On three separate days, exercise tests were performed 1 h a nd 12 h after administration of the drug, Pulmonary function measureme nts were performed before drug inhalation, before every exercise test and 1, 5, 10, 15 and 30 min after the end of exercise, The response wa s expressed as maximal decrease in forced expiratory volume in one sec ond (FEV(1)). Both doses of salmeterol provided significant bronchodil ation for up to 12 h, with no difference between them, Maximal exercis e-induced decrease in FEV(1) (% fall) 1 h after pretreatment was (mean +/-SD) 35+/-16, 10+/-10 and 4+/-3% for placebo, 25 and 50 mu g salmete rol, respectively. At 12 h after pretreatment these values were 31+/-1 4, 19+/-12 and 15+/-13%, respectively, Individual protection against e xercise-induced bronchoconstriction at 1 and 12 h did not vary between the dosages (p<0.05), even though the protection obtained by 25 mu g at 12 h was no longer significant versus placebo. We conclude that 25 mu g of inhaled salmeterol provides equally effective long-lasting bro nchodilation and acute protection against exercise-induced bronchocons triction as 50 mu g, and may be a suitable dose for most asthmatic chi ldren.