Purpose of review: The role of magnesium sulfate (MgSO4) in the treatment of acute asthma is not clear. Four recent systematic reviews suggest a limited role of intravenous (i.v.) and inhaled nebulized treatment. The purpose of this review is to summarize the current literature, focus on two recent large multicenter randomized controlled trials, and discuss future research directions.
Recent findings: The Magnesium Nebulized Trial In Children (MAGNETIC) trial has shown little benefit to routine use of nebulized MgSO4 in children with acute asthma, but there may be a benefit in those with severe exacerbations and a shorter duration of symptoms. The 3Mg trial has shown no role for nebulized MgSO4 in adults and, at best a limited role for i.v. MgSO4 in only the most severe exacerbations. This is the only study with direct comparison of nebulized and i.v. MgSO4.
Summary: MgSO4 has a role in severe exacerbations of acute asthma and there is no evidence of benefit outside this clinical situation. Both nebulized and i.v. treatments are well tolerated and inexpensive. In adults, the most effective route of administration is i.v. There are no direct comparison studies in children. Further research should focus on more severe exacerbations.