Mode of action of bronchodilating drugs on histamine-induced bronchoconstriction in asthmatic children.

The bronchodilatory response of three beta 2-agonists (fenoterol, salbutamol, and terbutaline), administered by a metered aerosol inhaler, was assessed in 19 asthmatic children after histamine-induced bronchoconstriction. At 1-min intervals, the changes in total pulmonary flow resistance (R1) and dynamic lung compliance (C dyn) were measured. After rank-ordering according to the base line value of C dyn (62 to 200% predicted), the patients were divided into two groups according to lung compliance: (1) patients with greater compliance (C dyn, 129 to 200% predicted) and (2) patients with lesser compliance (C dyn, 69 to 116% predicted).