Additive effects of isoproterenol-phenylephrine aerosol following ipratropium bromide on airway obstruction in older patients with intrinsic asthma and chronic bronchitis.

The additive bronchodilating effect of isoproterenol-phenylephrine aerosol following ipratropium bromide was examined in seven intrinsic asthmatic patients and seven chronic bronchitic patients. FVC, FEV1 and Zrs were measured before and 30 min. after inhalation of ipratropium, 40 micrograms. Then inhalation of isoproterenol, 600 micrograms and phenylephrine, 570 micrograms was added and the pulmonary functions were measured 30 min. later. The age, baseline values of FVC and FEV1, and the increases in FEV1 and 1/Zrs with ipratropium did not differ between the two. Isoproterenol-phenylephrine aerosol following ipratropium produced further increases in FEV1 and 1/Zrs in asthmatic patients but no additive increases in bronchitic patients. These findings indicate that the role of autonomic nervous system, especially adrenergic system, on airway obstruction may be different between asthmatic and bronchitic patients and the method applied in this study may be helpful in differentiating these airway disorders.