Question: In patients with stable asthma, is the standard chlorofluorocarbon-containing pressurized metered-dose inhaler (PMDI) as effective as other handheld inhaler devices, including chlorofluorocarbon-free PMDIs, for delivering β2-agonist bronchodilators?
Data sources: Studies published from 1966 to December 2000 were identified by searching the Cochrane Airways Group trials database (derived from MEDLINE, EMBASE/Excerpta Medica, CINAHL; hand searches of 20 relevant journals and proceedings of 3 respiratory societies; and review of the bibliographies of included trials). MEDLINE, EMBASE/Excerpta Medica, CINAHL, and 17 online respiratory Web sites were also independently searched, and pharmaceutical companies that manufacture inhaled asthma drugs were contacted for unpublished studies.
Study selection: Studies in any language were selected if they were laboratory-, hospital-, or community-based randomized controlled trials of children or adults that compared delivery of β2-agonist bronchodilators by standard PMDI (with or without a spacer) with any other handheld inhaler. Trials comparing different doses of inhaled drug and those that used challenge testing were also included.
Data extraction: 2 reviewers independently extracted data on study design, patient characteristics, details of the intervention, study duration, outcomes, and quality. Outcomes included lung function (FEV1), quality-of-life measurements, symptom scores, drugs for additional relief, steroid requirements, nocturnal awakening, acute exacerbations, days off work or school, treatment failures, patient compliance, patient preferences, adverse effects, bronchial hyperreactivity, and systemic bioavailability.
Main results: 89 articles describing 84 studies met the selection criteria. 71 trials involved adults, and 13 involved children. In most trials, patients had mild-to-moderate asthma (baseline FEV1 > 50% of predicted). Meta-analyses were done using a fixed-effects model. In both adults and children, standard PMDIs did not differ from any of the other 10 handheld inhaler devices (Turbohaler, Diskhaler, hydrofluoroalkane PMDI, Rotahaler, Spiros, Easyhaler, multidose-powder inhaler, Clickhaler, Gentlehaler, and Autohaler) for FEV1, forced vital capacity, peak expiratory flow rate, area under the curve for FEV1, blood pressure, symptoms, bronchial hyperreactivity, systemic bioavailability, inhaled steroid requirement, serum potassium level, or use of additional relief brochodilators. However, regular use of the hydrofluoralkane PMDI containing salbutamol was associated with reduced requirement for short courses of oral corticosteroids (relative risk 0.67, 95% CI 0.49 to 0.91).
Conclusion: In patients with stable asthma, the standard chlorofluorocarbon-containing pressurized metered-dose inhaler (PMDI) is as effective as other handheld inhalers, including chlorofluorocarbon-free PMDIs, for delivering β2-agonist bronchodilators.