Continuous treatment with a short-acting @entity2263 -agonist can lead to reduced bronchodilator responsiveness during acute bronchoconstriction. This study evaluated bronchodilator tolerance to @entity3045 following regular treatment with a long-acting @entity2263 -agonist, @entity6410 . The modifying effect of intravenous corticosteroid was also studied. Ten asthmatic subjects (using inhaled @entity230 ) participated in a randomised, double-blind, placebo-controlled, cross-over study. @entity6410 12 microg b.i.d. or matching placebo was given for 10-14 days with >2 weeks washout. Following each treatment, @entity1 underwent a @entity2710 challenge to induce a fall in forced expired volume in one second (FEV1) of at least 20%, then @entity3045 100 microg, 100 microg, and 200 microg was inhaled via a spacer at 5 min intervals, with a further 400 microg at 45 min. After a third single-blind @entity6410 treatment period, @entity701 200 mg was given intravenously prior to @entity3045 . Dose-response curves for change in FEV1 with @entity3045 were compared using analysis of covariance to take account of @entity2710 -induced changes in spirometry. Regular @entity6410 resulted in a significantly lower FEV1 after @entity3045 at each time point compared to placebo (p<0.01). The area under the curves (AUCs) for 15 (AUC0-15) and 45 (AUC0-45) min were 28.8% and 29.5% lower following @entity6410 treatment (p<0.001). Pretreatment with @entity701 had no significant modifying effect within 2 h of administration. It is concluded that significant tolerance to the bronchodilator effects of inhaled @entity3045 occurs 36 h after stopping the regular administration of @entity6410 . This bronchodilator tolerance is evident in circumstances of acute bronchconstriction.

Reversing acute bronchoconstriction in asthma: the effect of bronchodilator tolerance after treatment with XXXX .

@entity1 :: ('9606', 'Species') :: ['patients'] @entity230 :: ('MESH:D013256', 'Chemical') :: ['steroids'] @entity3045 :: ('MESH:D000420', 'Chemical') :: ['salbutamol'] @entity701 :: ('MESH:D006854', 'Chemical') :: ['hydrocortisone'] @entity2263 :: ('10242', 'Gene') :: ['beta2'] @entity6410 :: ('MESH:C012629', 'Chemical') :: ['Formoterol', 'formoterol'] @entity2710 :: ('MESH:D016210', 'Chemical') :: ['methacholine']
@entity6410 :: (MESH:C012629,Chemical) :: ['formoterol']
