Respiratory medicine
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Respiratory medicine · May 1994
Randomized Controlled Trial Comparative Study Clinical TrialReduced protection against exercise induced bronchoconstriction after chronic dosing with salmeterol.
The purpose of the present study was to assess the degree of protection of inhaled salmeterol against exercise-induced bronchoconstriction (EIB) after chronic compared with single dosing in patients with asthma. Twelve patients with exercise-induced asthma took part in a randomized double-blind crossover study to compare the duration of action of inhaled salmeterol 50 micrograms twice daily for 4 weeks with that of placebo. ⋯ The percentage fall in FEV1 after exercise challenge at 6 h was (first dose): placebo 34.8 +/- 4.9% vs. salmeterol 11.9 +/- 2.8% (P < 0.05); (4 weeks): placebo 32.9 +/- 5.3% vs. salmeterol 24.0 +/- 4.4% (NS). These results suggest that tachyphylaxis may develop to the functional antagonism of salmeterol against EIB.