Long-term study comparing fenoterol and isoproterenol inhalation in asthmatic patients.

In a parallel-group, double-blind study 28 chronic asthmatic patients were treated for 90 days with metered dose inhalers of fenoterol and isoproterenol, at daily doses of 0.4 mg t.i.d. and 0.15 mg t.i.d., respectively. Fenoterol produced significant improvements in FEV1 and FEF25-75%, greater than those achieved with isoproterenol, in tests on days 1, 45 and 90; its median duration of action was two to four times longer than that of isoproterenol. Ratings for overall responses to treatment were higher for fenoterol and mean attack rates showed a greater decline than with isoproterenol.