Duration of oral procaterol protection from methacholine-induced bronchial obstruction.

The duration of action of procaterol, a beta-2-adrenoceptor agonist with an entirely new chemical structure, was assessed, in comparison to that of salbutamol, by inhalation of 43 inhalation units of methacholine at time intervals of 1, 3, 5, 7, and 9 hours after intake of the drugs. Procaterol and salbutamol were given in a double-blind random fashion, on different days, to 12 asthmatic children; pulmonary function tests (FVC, FEV1, MEF50, MEF25), skeletal muscle tremor, and vital signs (heart rate and blood pressure) were measured. Although there was no statistical significant difference between procaterol and salbutamol, protection of large and medium airways lasted for about five hours, while normal small airway patency was still present at seven hours. It is concluded that procaterol can be a good alternative beta-2-adrenoceptor agonist when the oral route is needed.