Safety of formoterol Turbuhaler® at cumulative dose of 90 µg in patients with acute bronchial obstruction

This study compared the safety of formoterol (Oxis® Turbuhaler®; 90 µg delivered dose; 120 µg metered dose) with terbutaline (Bricanyl® Turbuhaler®; 10 mg), in patients with acute bronchoconstriction. Forty-eight patients (31 females) with a mean age of 45 yrs, were randomized into two parallel groups (double-blind design). Mean baseline forced expiratory volume in one second (FEV 1 ) was 0.98 L (33% of predicted normal). Study drugs were administered on six occasions during 3 h (formoterol 4.5 µg or terbutaline 0.5 mg·inhalation −1 , 20 inhalations). Patients received intravenous prednisolone after 1.5 h and oxygen during the first 3 h. Pulse rate, serum potassium, 12-lead electrocardiogram (ECG), Holter ECG, arterial blood gases and FEV 1 were assessed during 12 h after the first dose. Four patients (one formoterol, three terbutaline) discontinued. The 12-h mean values of serum potassium decreased from 4.02 to 3.89 mmol·L −1 for formoterol and from 4.22 to 3.76 mmol·L −1 for terbutaline. Mean 12-h pulse rate was significantly (p 1 improved in both groups but with no statistically significant difference between treatments. Oxis® Turbuhaler® (90 µg) was at least as safe and well tolerated as terbutaline (110 mg) in patients with acute bronchoconstriction.