The Journal of allergy and clinical immunology
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J. Allergy Clin. Immunol. · May 1999
Randomized Controlled Trial Clinical TrialIn vivo effect of albuterol on methacholine-contracted bronchi in conjunction with salmeterol and formoterol.
It has been shown in vitro that prior treatment with salmeterol and formoterol antagonizes the relaxant effect of albuterol in carbachol-contracted human bronchi. ⋯ Compared with placebo, both salmeterol and formoterol caused a significant degree of antagonism of albuterol-induced bronchorelaxation in methacholine-contracted bronchi in vivo. This interaction could be caused by prolonged occupancy of airway beta2-adrenoceptors by long-acting beta2-agonists or by early tachyphylaxis 12 hours after a single-dose exposure. The degree of albuterol protection was also related to beta2-adrenoceptor polymorphism.