Review: Pressurized metered-dose inhalers are as effective as other handheld inhalers for corticosteroid use in asthma

Question: In patients with stable asthma, is the standard chlorofluorocarbon-containing pressurized metered-dose inhaler (PMDI) as effective as other handheld inhaler devices for delivering corticosteroids?

Data sources: Studies published from 1966 to July 1999 were identified by searching the Cochrane Airways Group trials database (derived from MEDLINE, EMBASE/Excerpta Medica, CINAHL; hand searches of 18 relevant journals and proceedings of 3 respiratory societies; and reviews of bibliographies of relevant studies). Pharmaceutical companies that manufacture inhaled asthma drugs were contacted for unpublished studies.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 lasted ≥ 4 weeks and compared a single drug delivered by a standard PMDI (with or without a spacer) with any other handheld inhaler. Trials comparing different doses of the same drug 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, acute exacerbation, days off work or school, treatment failure, patient compliance, patient preference, adverse effects, bronchial hyperreactivity, and systemic bioavailibility.

Main results: 24 articles describing 29 studies met the selection criteria. 14 studies compared PMDIs with dry-powder inhalers (DPIs): PMDIs were less effective than DPIs for improving FEV₁ and morning peak expiratory flow rate and for reducing use of additional relief drugs (Table). However, these differences either disappeared after adjustment for baseline variables or were within clinically equivalent limits. 11 studies compared chlorofluorocarbon PMDI with hydrofluoroalkane (10 studies used beclomethasone, and 1 study used fluticasone). Treatment effects did not differ. 1 study compared breath-actuated PMDI with PMDI but found no differences for any outcomes. 3 studies of children were included, but a meta-analysis of the results could not be done because of study differences. None of the studies of children found any differences in pulmonary function between the devices. However, 1 study found that the Turbohaler group reduced their use of relief drugs by 1 puff per week (95% CI 0.35 to 1.96) more than the PMDI group.

Conclusion: In patients with stable asthma, the standard chlorofluorocarbon-containing pressurized metered-dose inhaler is as effective as other handheld inhaler devices for delivering corticosteroids.