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

This study compared the safety of formoterol (Oxis R Turbuhaler R; 90 mug delivered dose; 120 mug metered dose) with terbutaline (Bricanyl R Turbuhaler R; 10 mg), in patients with acute bronchoconstriction. Forty-eight patients (31 females) with a mean age of 4-5 yrs, were randomized into two parallel groups (double-blind design). Mean baseline forced expiratory volume in one second (FEV1) was 0.98 L (33% of predicted normal). Study drugs were administered on six occasions during 3 h (formoterol 4.5 mug 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 FEV1 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<0.01) higher in the terbutaline group (101.7 beats per minute (bpm)) than in the formoterol group (93.5 bpm). No individual patient value was considered clinically important or alarming. FEV1 improved in both groups but with no statistically significant difference between treatments. Oxis (R) over bar Turbuhaler (R) over bar (90 mug) was at least as safe and well tolerated as terbutaline (110 mg) in patients with acute bronchoconstriction.