Do magnesium sulfate infusions reduce the need for hospital admission in children with acute asthma?


Many children experience life-threatening asthma attacks and require treatment in the hospital emergency department. Some national and international asthma treatment guidelines recommend giving an infusion of a drug called magnesium sulfate (IV MgSO4) to children having asthma attacks that have not responded well to other treatments. This has been shown to reduce the need for hospital admission for adults, but it is unclear whether it is safe and similarly effective for children.

Study characteristics

We found five studies in children that compared an infusion of MgSO4 to a placebo infusion when other treatments had not relieved the attack (usually inhaled bronchodilators, steroids, and sometimes oxygen). These five studies included a total of 182 children. Only three of the studies reported the outcome we were most interested in, which was the need to be admitted to hospital. The studies were published between 1996 and 2000; these were the most current studies we could find when we searched in February 2016.

Key results and quality of the evidence

Fewer children who had an infusion of MgSO4 needed to be admitted to hospital compared with placebo. In fact, for every five children treated with the MgSO4, one admission to hospital was prevented. However, the included studies were small, with only 115 children in the main analysis, and the results did vary, so we cannot be absolutely sure of the benefits and harms. As there were so few studies, we also could not tell whether the reduction in hospital admissions was associated with age, severity of the asthma exacerbation, or whether it made a difference what other treatments were given. There were no reports of harm when the children received MgSO4. The review therefore supports the use of MgSO4 in children, however it must be noted that the evidence for its use is very weak.

Authors' conclusions: 

IV MgSO4 may reduce the need for hospital admission in children presenting to the ED with moderate to severe exacerbations of asthma, but the evidence is extremely limited by the number and size of studies. Few side effects of the treatment were reported, but the data were extremely limited.

Read the full abstract...

Acute asthma in children can be life-threatening and must be treated promptly in the emergency setting. Intravenous magnesium sulfate is recommended by various guidelines for cases of acute asthma that have not responded to first-line treatment with bronchodilators and steroids. The treatment has recently been shown to reduce the need for hospital admission for adults compared with placebo, but it is unclear whether it is equally effective for children.


To assess the safety and efficacy of intravenous magnesium sulfate (IV MgSO4) in children treated for acute asthma in the emergency department (ED).

Search strategy: 

We identified studies by searching the Cochrane Airways Review Group Specialised Register up to 23 February 2016. We also searched and reference lists of other reviews, and we contacted study authors to ask for additional information.

Selection criteria: 

We included randomised controlled trials of children treated in the ED for exacerbations of asthma if they compared any dose of IV MgSO4 with placebo.

Data collection and analysis: 

Two review authors screened the results of the search and independently extracted data from studies meeting the inclusion criteria. We resolved disagreements through discussion and contacted study authors in cases of missing data and other uncertainties relating to the studies.

We analysed dichotomous data as odds ratios and continuous data as mean differences, both using fixed-effect models. We assessed each study for risk of bias and rated the quality of evidence for each outcome with GRADE and presented the results in a 'Summary of findings' table. There was insufficient evidence to conduct the planned subgroup analyses.

Main results: 

Five studies (182 children) met the inclusion criteria, and four contributed data to at least one meta-analysis. The included studies were overall at low risk of bias, but our confidence in the evidence was generally low, mainly due to the small sample sizes. Treatment with IV MgSO4 reduced the odds of admission to hospital by 68% (odds ratio (OR) 0.32, 95% confidence interval (CI) 0.14 to 0.74; children = 115; studies = 3; I2 = 63%). This result was based on data from just three studies including 115 children. Meta-analysis for the secondary outcomes was extremely limited by paucity of data. We performed meta-analysis for the outcome 'return to the emergency department within 48 hours', which showed a very imprecise effect estimate that was not statistically significant (OR 0.40, 95% CI 0.02 to 10.30; children = 85; studies = 2; I2 = 0%). Side effects and adverse events were not consistently reported and meta-analysis was not possible, however few side effects or adverse events were reported.