Salbutamol via Easyhaler (R) multidose dry powder inhaler produces equivalent relief of histamine-induced bronchoconstriction to salbutamol via pressurised metered-dose inhaler

Objective: The objective of the study was to compare the clinical efficacy and acceptability of inhaling a single 100 mu g dose of salbutamol via eith er an Easyhaler(R) multidose dry powder inhaler or a pressurised metered-do se inhaler (pMDI) in the treatment of histamine-induced bronchoconstriction . Design: The study was conducted using a double-blind, double-dummy, randomi sed, crossover design. Participants: 20 adults with asthma and/or bronchial hyper-reactivity compl eted the study. Methods: A histamine challenge test was carried out on 2 tudy days separate d by a maximum of 1 week. Patients inhaled doubling doses of histamine unti l a 20% decrease in forced expiratory volume in 1 second (FEV1) was achieve d. They then inhaled a single 100 mu g dose of salbutamol via Easyhaler(R) or pMDI. Lung function variables, including FEV1, forced vital capacity (FV C), area under the maximal flow-volume curve (AFV) and maximal expiratory f low at 50% of vital capacity (MEF50) were assessed by flow-volume spirometr y before and after the histamine challenge, and 5, 15 and 60 minutes after salbutamol inhalation. On the second study day, the acceptability of the in halers was evaluated using a questionnaire. Results: Changes in FEV1 values were similar with both devices: the maximum percentage improvement in FEV I from the post-challenge Value was 35.6 +/- 8.8% with Easyhaler(R) and 40.2 +/- 16.1% with pMDI (95% confidence interv al for difference, -6.5 to 4.2%). The maximum improvement in absolute FEV1 values was 0.83 +/- 0.31L with Easyhaler(R) and 0.87 +/- 0.34L with pMDI. T he maximum percentage improvements in FVC, AFV and MEF50 from the post-chal lenge value were also similar with both treatments. However, the onset of b ronchodilation (FEV1) was faster with Easyhaler(R). From the results of the questionnaire, all patients would have chosen Easyhaler(R) for personal us e. Conclusion: The results show that salbutamol via Easyhaler(R) is as effecti ve at dilating the large and small airways after histamine challenge as sal butamol via pMDI. Moreover, the onset of bronchodilation was faster with Ea syhaler(R), which was also preferred to pMDI by all patients.