Aerosolized magnesium sulfate for acute asthma: a systematic review.
BACKGROUND
The use of MgSO(4) is one of numerous treatment options available during exacerbations of asthma. While the efficacy of therapy with IV MgSO(4) has been demonstrated, little is known about inhaled MgSO(4).


OBJECTIVE
A systematic review of the literature was performed to examine the effect of inhaled MgSO(4) in the treatment of patients with asthma exacerbations in the emergency department.


METHODS
Randomized controlled trials were eligible for inclusion and were identified from the Cochrane Airways Group "Asthma and Wheez*" register, which consists of a combined search of the EMBASE, CENTRAL, MEDLINE, and CINAHL databases and the manual searching of 20 key respiratory journals. Reference lists of published studies were searched, and a review of the gray literature was also performed. Studies were included if patients had been treated with nebulized MgSO(4) alone or in combination with beta(2)-agonists and were compared to the use of beta(2)-agonists alone or with an inactive control substance. Trial selection, data extraction, and methodological quality were assessed by two independent reviewers. The results from fixed-effects models are presented as standardized mean differences (SMDs) for pulmonary functions and the relative risks (RRs) for hospital admission. Both are displayed with their 95% confidence intervals (CIs).


RESULTS
Six trials involving 296 patients were included. There was a non-significant increase [corrected] in pulmonary function between patients whose treatments included nebulized MgSO(4) and those whose treatments [corrected] did not (SMD, 0.22; 95% CI, -0.02 to 0.47 [corrected] five studies); there was also a trend toward reduced [corrected] hospitalizations in patients whose treatments included nebulized MgSO(4) (RR, 0.67; 95% CI, 0.41 to 1.09; four studies). Subgroup analyses demonstrated that lung function improvement was similar in adult patients and in those patients who received nebulized MgSO(4) in addition to a beta(2)-agonist.


CONCLUSIONS
The use of nebulized MgSO(4), particularly in addition to a beta(2)-agonist, in the treatment of an acute asthma exacerbation appears to produce benefits with respect to improved pulmonary function and may reduce the number of hospital admissions.
Department of Emergency Medicine, 1G1.43 WMC, 8440-112 Street, Edmonton, Alberta, Canada T6G 2B7.
Maurice
M
Blitz
Sandra
S
Blitz
Rodney
R
Hughes
Barry
B
Diner
Richard
R
Beasley
Jennifer
J
Knopp
Brian H
BH
Rowe
D000208:Acute Disease; D000280:Administration, Inhalation; D000318:Adrenergic beta-Agonists / Q000627:therapeutic use; D000336:Aerosols; D018927:Anti-Asthmatic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D001249:Asthma / Q000188:drug therapy*; D006801:Humans; D008278:Magnesium Sulfate / Q000008:administration & dosage / Q000627:therapeutic use*; D009330:Nebulizers and Vaporizers; D016032:Randomized Controlled Trials as Topic
D000318:Adrenergic beta-Agonists; D000336:Aerosols; D018927:Anti-Asthmatic Agents; D008278:Magnesium Sulfate