Histamine Bronchoconstriction Reduces Airway Responsiveness in Asthmatic Subjects

Tachyphylaxis occurs to repeated challenges with inhaled histamine but not with inhaled acetylcholine in asthmatic subjects. This study was undertaken to determine whether prior histamine bronchoconstriction reduces airway responsiveness to inhaled acetylcholine in mild asthmatic subjects demonstrating histamine tachyphylaxis. All subjects developed histamine tachyphylaxis with repeated histamine challenge. The mean histamine PC20 increased …