Low-dose formoterol Turbuhaler (Oxis) b.i.d., a 3-month placebo-controlled comparison with terbutaline (q.i.d.).

This study compared the efficacy of a low dose of formoterol Turbuhaler 6 micrograms b.i.d. (F) with that of terbutaline 0.5 mg q.i.d. (T), and placebo (P) from Turbuhaler. After a 2-week run-in, 397 adults with mild to moderate asthma were randomly allocated to one of the treatments for 12 weeks. During run-in, the mean morning peak expiratory flow (PEF) was 360 (F), 368 (T) and 367 1 min-1 (P). F was better than T (P = 0.014) and P (P = 0.0001) in improving morning PEF [mean changes from run-in: 20 (F), 9 (T), and 21 min-1 (P)]. F was statistically significantly more effective than either T or P in reducing asthma symptoms. F gave also statistically significantly higher evening PEF and less use of rescue medication than P. Bronchodilator response to study drugs and additional 1.25 mg terbutaline was similar before and after the 12-week treatment period. There were no adverse effects of clinical relevance. In conclusion, formoterol Turbuhaler, 6 micrograms b.i.d. was more effective in improving PEF and offered better asthma control than either terbutaline Turbuhaler, 0.5 mg q.i.d. or placebo. Regular use of formoterol did not reduce the bronchodilator response to additional terbutaline. There were no clinically relevant adverse effects.