Comparison of the bronchodilating effects of SCH 1000 with isoproterenol in patients with bronchial asthma.

The effect of SCH 1000 and isoproterenol was evaluated in 10 patients with extrinsic asthma. The onset of action for the SCH 1000 dose compared to the baseline response occurred at or before 15 minutes (FEV1 and MEFR). The onset of action for the isoproterenol dose occurred at or before one minute for all three pulmonary function variables. At the 1-, 3-, 6- and 15-minute intervals the response to the isoproterenol dose was significantly greater than the response to the SCH 1000 dose for FEV1, FVC and MEFR. At 30 and 60 minutes, however, the response to SCH 1000 was progressively increasing, whereas the response to isoproterenol was decreasing. The maximum improvement in FEV1 for isoproterenol was 49% at three and six minutes, whereas for SCH 1000 was 28% at 60 minutes. In patients with chronic bronchitis or bronchial asthma SCH 1000 may be considered as a therapeutic alternative to beta-adrenergic bronchodilators and in patients who also have cardiac arrythmias or angina pectoris and are adversely affected by sympathomimetic drugs.