Comparison of bronchodilating effects of two salbutamol dry powder inhalers in asthmatic patients.

In an open, randomized crossover study two different types of dry powder inhalers (DPIs) were compared. Twenty-five adult asthmatic patients inhaled a single dose of 200 μg of salbutamol (CAS 18559-94-9) on two separate days. Salbutamol was administered either from a novel multidose DPI (Easyhaler®, test DPI) or from another type of DPI (reference DPI). On both study days lung function, blood pressure and heart rate were measured during a 4-h follow-up period. Both powder inhalers caused a clear increase in lung function parameters. The mean (SD) maximum forced expiratory volume in 1 s (FEV 1 ) after the test DPI was 3.25 (1.30)1 and after the reference DPI 3.28 (1.29) 1. The mean relative change from the baseline in FEV 1 was similar after administration of both preparations. The mean area under the curve (AUC 0-4h ) of the absolute FEV 1 values was 729 (316) and 731 (309) 1x min after test and reference DPIs, respectively. The salbutamol doses had no clinically significant effects on blood pressure or heart rate and were equally well tolerated. Furthermore, 41 % of patients preferred the test DPI and 19 % the reference DPI, while 40 % felt there was no difference between the devices. In conclusion, the results of this study show that the test DPI, a novel multidose powder inhaler, is an effective, safe and convenient alternative when an inhaled bronchodilator treatment is considered for an obstructive patient.