Bronchodilating effects of salbutamol from a novel inhaler Airmax

This randomized, placebo-controlled, evaluator-blind, five-way crossover study compared the equivalence in terms of FEV1 response to single ascending cumulative doses of salbutamol (100-400 micrograms) from Airmax, a new multidose dry powder inhaler, in comparison with placebo, the same dose from a standard pressurized metered dose inhaler (Ventolin) or at double the dose from the dry powder inhalers Diskhaler and Accuhaler. Sixty-one adult asthmatic subjects with FEV150-80% predicted and > or = 15% increase in FEV1 to salbutamol took part. Equivalence was declared if the 95% CI for the ratio of the FEV1 responses to the two treatments was within the range 90-111%. Following the cumulative four doses, FEV1 (1) changes pre-dose to the highest dose were: 2.53-3.31, 2.47-3.30, 2.51-3.35, 2.52-3.31 and 2.57-2.55 for Airmax salbutamol, salbutamol Ventolin, salbutamol Diskhaler, salbutamol Accuhaler and placebo, respectively. The 95% CIs for the ratio of Airmax salbutamol to each of the active devices were within +/- 5% demonstrating a 1:1 dose equivalence between Airmax salbutamol and Ventolin and a 1:2 dose equivalence between each of the other two salbutamol dry powder devices. Adverse events profiles were similar for all treatments. In conclusion, the novel multidose inhaler Airmax salbutamol is as efficacious and safe as the pressurized metered dose inhaler without the need for co-ordinating actuation and inhalation and with the added benefit of a dose counter.