FEV1 Response to Bronchodilation with HFA Fenoterol and CFC Fenoterol by Inhalation

Objectives: Chlorofluorocarbon metered-dose inhalers (CFC-MDIs) have been reformulated, and now, the non-ozone-depleting propellant, hydrofluoroalkane, is used in metered-dose inhalers (HFA-MDIs). The aim of the study was to evaluate the bronchodilation response of the 2 products.Methods: We assessed bronchodilation by measuring FEV1 before and after inhalation of fenoterol CFC-MDI 400 mcg (2 puffs), fenoterol HFA-MDI 200 mcg (2 puffs) or fenoterol HFAMDI 400 mcg (4 puffs) delivered using a spacer.Results: Of the 3449 outpatients tested, those who had a positive bronchodilator result, defined as ΔFEV1 ＞12% and 200 mL, were enrolled in the study. The percentage of positive bronchodilation results in the fenoterol CFC-MDI (400 mcg) group was 19.0% (108/569), that in the fenoterol HFA-MDI (200 mcg) group was 14.4% (138/957) and in the HFA-MDI (400 mcg) group was 15.9% (148/928). FEV1 responses to bronchodilation (absolute ΔFEV1) were similar between the fenoterol CFC-MDI (400 mcg) group, fenoterol HFA-MDI (400 mcg) group, and fenoterol HFA-MDI (400 mcg) group (380.7 ± 176.5 mL vs. 344.1 ± 132.0 mL vs. 340.2 ± 142.6 mL, p=0.072).Conclusions: This study shows that fenoterol HFA-MDI and fenoterol CFC-MDI provide a comparable bronchodilation response. Inhaled fenoterol 400 mcg is better than fenoterol 200 mcg for testing the reversibility of airflow limitation. (Thorac Med 2012; 27: 143-149)