Effect of bronkosol and its components on cardiopulmonary parameters in asthmatic patients.

Bronkosol and its components, isoetharine hydrochloride and phenylephrine hydrochloride, were compared in a double-blind randomized fashion for their effect on pulmonary and cardiovascular parameters in patients with reversible bronchospasm. Bronkosol and isoetharine produced significant bronchodilatation as measured by forced expiratory volume in one second (FEV), forced vital capacity (FVC), and mean forced expiratory flow during the middle half of the FVC (isovolume FEF 25% to 75%), and phenylephrine did not. There was no difference between Bronkosol and isoetharine in the degree or duration of bronchodilatation. Significantly more patients had to "discontinue" after 15 min on the day of testing with phenylephrine than with Bronkosol or isoetharine. Heart rate was not increased after Bronkosol or isoetharine, confirming its selective beta-2 action. The addition of phenylephrine to isoetharine had no beneficial effect on oxygen saturation. There was no significant difference between these drugs in systolic and diastolic blood pressure, pulse, or respiration. The results of this study cast doubt on the useful contribution of phenylephrine in Bronkosol.