Study objective: Comparison of the bronchodilator response to an albuterol novel dry powder inhaler (DPI) (Clickhaler [CH]; ML Laboratories PLC; St. Albans, UK) activated at various inspiratory flow rates and to an albuterol pressurized metered-dose inhaler (pMDI) by patients with moderate to moderately severe stable asthma.
Design: Randomized, double-blind, placebo-controlled comparison of the bronchodilator response to albuterol DPI (200 microg) at inspiratory flow rates of approximately 15, 30, and 60 L/min in patients with stable asthma with demonstrated reversibility to albuterol. Active (albuterol via pMDI inhaled at 30 L/min) and placebo controls were included.
Setting: Single center study at the chest/allergy unit of a teaching hospital in Canada.
Patients: Sixteen patients with moderate to moderately severe stable asthma.
Measurements and results: Efficacy end points were FEV1, FVC, FEV1/FVC, maximum expiratory flow, and forced expiratory flow between 25% and 75% of vital capacity. Safety end points included heart rate, BP, and tremor. There was no significant difference between the bronchodilator response to albuterol via the CH at 15, 30, and 60 L/min inspiratory flow rate and, at all flow rates, no significant difference was found comparing albuterol CH with the pMDI. All of the techniques for delivering albuterol provided significantly better bronchodilatation than placebo. Adverse events were minimal and did not differ between CH and pMDI or between the various flow rates inhaled through the CH.
Conclusion: A novel passive albuterol DPI (CH) provides a similar bronchodilator response at 15, 30, and 60 L/min inspiratory flow rates compared with a pMDI used optimally.