Inhaled Corticosteroids Do Not Prevent the Development of Tolerance to the Bronchoprotective Effect of Salmeterol

摘要: Introduction Twice-daily inhaled salmeterol produces rapid reduction in its acute bronchoprotective effect against methacholine patients with mild asthma. This investigation examined this moderate asthma who were using corticosteroids. Subjects and methods Eight asthmatic volunteers required corticosteroids for control of their symptoms able to withhold treatment β 2 -agonists 4 weeks before during the study participated a double-blind, crossover, placebo-controlled two random-order periods: salmeterol, 50 pg twice day seven doses, placebo similar fashion, 7-day or greater washout between these periods. Methacholine inhalation tests done 1 h after doses 1, 3, 5, 7, then 24 last dose inhaler, 10 min post-200 salbutamol. Results Baseline FEV measurements 7 ie , 12 significantly higher than all other baseline values. Twenty-four hours was no different from that period. The geometric mean concentration causing 20% fall (PC 20 ) following third (6.8 mg/mL) lower first (12.0 mg/mL; p=0.031), bronchoprotection persisted 5 7. PC postsalbutamol measured period (5.6 vs 13.3 p Conclusions Tolerance significant seventh dose. salbutamol also regular use doses. These effects, subjects regularly, those previously seen asrequired only, indicating tolerance is not prevented by