The increased prevalence of asthma in children has been accompanied by a rise in morbidity and mortality. Treatment for children presenting to emergency departments with moderate or severe exacerbation of asthma includes aggressive use of beta₂ agonists and systemic corticosteroids. Some children require hospitalization even with aggressive therapy. Magnesium sulfate has been used for more than 50 years to treat status asthmaticus and severe acute asthma without specific guidelines. Scarfone and associates studied the early administration of magnesium to moderately to severely ill children with asthma in a randomized, double-blind, placebo-controlled clinical trial.

The major outcome was the change in clinical asthma score over time; secondary outcome measures included hospitalization rates and time required to meet discharge criteria. The study enrolled patients between two and 18 years of age with a past history of at least one prior episode of wheezing who presented to the emergency department with a moderate to severe asthma exacerbation. Patients who had used corticosteroids within 72 hours and who had any of a number of pulmonary, heart, liver or renal diseases were excluded. Pregnant patients also were excluded. Severity of asthma was scored using the pulmonary index (PI). All children were initially treated with inhaled nebulized albuterol followed by a second albuterol treatment and intravenous methylprednisolone.

Study participants were randomly given either 75 mg per kg (maximum: 2.5 g) of intravenous magnesium sulfate or intravenous placebo (normal saline). All patients received three more albuterol treatments over the next two hours. Clinical assessment was performed at specific intervals to record PI score, oxygen saturation, pulse and blood pressure, and adverse effects were noted. Discharge criteria included sustained good aeration, absent or minimal wheezing, minimal work of breathing and an oxygen saturation greater than 95 percent in room air. All patients went home and continued using inhaled albuterol and oral prednisone for five days.

Of the 54 study subjects, 24 received magnesium sulfate and 30 received placebo. Children in both groups experienced a significant improvement in mean PI scores from baseline to 120 minutes. The authors found no evidence of a magnesium benefit nor did they find a difference in hospitalization rates between the two groups. Side effects of magnesium infusion were mild and included transient facial warmth, dry mouth and malaise.

The authors conclude that among a cohort of moderately to severely ill asthmatic children treated with aggressive beta₂-agonist therapy and intravenous corticosteroids, high-dose magnesium offered no additional benefit when administered early in the course of treatment.