Double-blind one-year clinical study of fenoterol metered dose inhaler: preliminary results of a cooperative study.

As part of a controlled multi-center study 44 chronic asthmatics were treated for one year with either fenoterol (0.4 mg t.i.d. or q.i.d.) or isoproterenol (0.15 mg t.i.d. or q.i.d.) by metered dose inhaler. According to spirometric tests, fenoterol significantly improved pulmonary function until the end; isoproterenol became less effective after six months. Periodic global evaluations also gave no evidence of tolerance developing to femoterol. Side effects remained within acceptable limits.