Higher-dose intravenous magnesium therapy for children with moderate to severe acute asthma

OBJECTIVE: To evaluate the efficacy of a 40-mg/kg dose of intravenous magnesium sulfate for moderate to severe asthma exacerbations in pediatric patients. STUDY DESIGN: Double-blind placebo-controlled trial. SETTING: Two urban tertiary care pediatric emergency departments. SUBJECTS: Thirty patients, aged 6 to 17.9 years, being treated for an acute asthma exacerbation. INTERVENTION: Eligible patients received either a magnesium sulfate infusion of 40 mg/kg or saline solution. RESULTS: At 20 minutes, the time at which the infusion was completed, the magnesium group had a significantly greater percentage of absolute improvement from baseline in each of the following: predicted peak expiratory flow rate (8.6% vs 0.3%, P<. 001), forced expiratory volume in 1 second (7.0% vs 0.2%,P<.001), and forced vital capacity (7.3% vs -0.7%, P<.001). The improvement was greater at 110 minutes: peak expiratory flow rate (25.8% vs 1.9%, P<.001), forced expiratory volume in 1 second (24.1% vs 2.3%; P<. 001), and forced vital capacity (27.3% vs 2.6%, P<.001). Patients who received intravenous magnesium were more likely to be discharged to their homes than those who received the placebo (8/16 vs 0/14; P=. 002). CONCLUSION: Children treated with 40 mg/kg of intravenous magnesium sulfate for moderate to severe asthma showed remarkable improvement in short-term pulmonary function.