The bronchoprotective efficacy of salbutamol inhaled from a new metered-dose powder inhaler compared with a conventional pressurized metered-dose inhaler connected to a spacer

Abstract

The aim of this study was to compare the efficacy of 100 μg of salbutamol inhaled from a new metered-dose powder inhaler (MDPI, Leiras Taifun ®, Finland) with that of a same dose of salbutamol inhaled from a conventional pressurized metered-dose inhaler with a large volume spacer (pMDI+S) in protecting against methacholine (Mch) induced bronchoconstriction. This was a 3 day, randomized, cross-over, partly blinded, placebo-controlled multicentre study where the pMDI+S was used as an open control. Twenty-six asthmatic outpatients with a baseline FEV 1≥60% of predicted and with bronchial hyperreactivity (PD 20FEV 1≤890 μg of Mch) were studied. On each study day the patients underwent an Mch provocation 30 min after inhaling placebo from the MDPI or a dose of 100 μg of salbutamol from the MDPI and from the pMDI+S. PD 20 FEV 1 and dose-response slope [DRS; maximal change in FEV 1 (%)/dose of Mch (μmol)] were used to evaluate efficacy. The median values of PD 20 FEV 1 were 250, 622 and 1737 μg after placebo MDPI, salbutamol pMDI+S and salbutamol MDPI, respectively. The corresponding DRS values were − 11.0%, − 4.5% and − 2.0% μmol −1. With both parameters, all differences were statistically significant ( P<0·05). In conclusion, 100 μg of salbutamol inhaled from Leiras Taifun ® MDPI offers better protection against Mch-induced bronchoconstriction than 100 μg of salbutamol from a pMDI connected to a large volume spacer device.