Inhaled magnesium sulfate in the treatment of acute asthma

Blitz M, Blitz S, Beasely R, Diner B, Hughes R, Knopp JA, Rowe BH

Published Online:

July 8, 2009

Acute asthma is a common emergency department problem usually treated with systemic corticosteroids, inhaled beta-agonists and a variety of other agents (including inhaled corticosteroids, inhaled anticholinergics, intravenous magnesium, oxygen, etc). Intravenous magnesium sulfate has demonstrated efficacy in acute severe asthma and this review identified evidence to demonstrate that using inhaled magnesium sulfate combined with a beta-2-agonist (β2-agonist) for an acute asthma exacerbation provides beneficial effects with respect to improved pulmonary function. The evidence, however, that nebulised magnesium sulfate positively impacts the clinically more important outcomes, such as hospital admissions, are lacking.

Abstract (click to read)

Background:

Asthma exacerbations can be frequent and range in severity from relatively mild to status asthmaticus. The use of magnesium sulfate (MgSO4) is one of numerous treatment options available during acute exacerbations. While the efficacy of intravenous MgSO4 has been demonstrated, little is known about inhaled MgSO4.

Objectives:

To examine the efficacy of inhaled MgSO4 in the treatment asthma exacerbations.

Search strategy:

Randomised controlled trials were identified from the Cochrane Airways Group "Asthma and Wheez*" register. These trials were supplemented with trials found in the reference list of published studies, studies found using extensive electronic search techniques, as well as a review of the grey literature and conference proceedings.

Selection criteria:

Randomised (or pseudo-randomised) controlled trials were eligible for inclusion. Studies were included if patients were treated with nebulised MgSO4 alone or in combination with β2-agonist and where compared to β2-agonist alone or inactive control.

Data collection and analysis:

Trial selection, data extraction and methodological quality were assessed by two independent reviewers. Efforts were made to collect missing data from authors. Results from fixed effects models are presented as standardized mean differences (SMD) for pulmonary functions and relative risks (RR) for hospital admission; both are displayed with their 95% confidence intervals (95% CI).

Main results:

Six trials involving 296 patients were included. Four studies compared nebulised MgSO4 with β2-agonist to β2-agonist and two studies compared MgSO4 to β2-agonist alone. Three studies enrolled only adults and 2 enrolled exclusively pediatric patients; three of the studies enrolled severe asthmatics. Overall, there was a non significant improvement in pulmonary function between patients whose treatments included nebulised MgSO4 in addition to β2-agonist (SMD: 0.23; 95% CI: -0.03 to 0.50; 4 studies). Hospitalizations were similar between the groups (RR: 0.69; 95% CI: 0.42 to 1.12; 3 studies). Subgroup analyses did not demonstrate significant differences in lung function improvement between adults and children, but in severe asthmatics the lung function difference was significant (SMD: 0.55; 95% CI: 0.12 to 0.98). Conclusions regarding treatment with nebulised MgSO4 alone are difficult to draw due to lack of studies in this area.

Authors' conclusions:

Nebulised inhaled magnesium sulfate in addition to β2-agonist in the treatment of an acute asthma exacerbation, appears to have benefits with respect to improved pulmonary function in patients with severe asthma and there is a trend towards benefit in hospital admission. Heterogeneity between trials included in this review precludes a more definitive conclusion.

This record should be cited as:

Blitz M, Blitz S, Beasely R, Diner B, Hughes R, Knopp JA, Rowe BH. Inhaled magnesium sulfate in the treatment of acute asthma. Cochrane Database of Systematic Reviews 2005, Issue 4. Art. No.: CD003898. DOI: 10.1002/14651858.CD003898.pub4

Assessed as up to date:

August 22, 2005

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Primary Review Group:

Airways Group

Asthma topics:

Treating with Medications > Asthma Attacks > Magnesium

Health topics:

Lungs & airways > Asthma (acute) > Other medications

Cochrane Summaries^beta

Independent high-quality evidence for health care decision making

Inhaled magnesium sulfate in the treatment of acute asthma

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