Intravenous magnesium for acute asthma: failure to decrease emergency treatment duration or need for hospitalization.

STUDY OBJECTIVE: To evaluate the efficacy of routine early administration of i.v. magnesium to patients with acute asthma. DESIGN: Prospective, randomized clinical trial. SETTING: Urban teaching hospital emergency department. TYPE OF PARTICIPANTS: One hundred twenty consecutive patients aged 18 to 65 years with acute asthma unresponsive to a single albuterol treatment. INTERVENTIONS: All patients received oxygen, 125 mg i.v. methylprednisolone, and hourly albuterol inhalation therapy. The study group also received 2 g i.v. magnesium sulfate infused over 20 minutes. MEASUREMENTS AND MAIN RESULTS: Demographic and clinical characteristics were similar in both groups. Hospitalization was necessary in 13 of 58 patients who received magnesium (22%; 95% confidence intervals [CI], 13% to 32%) and 11 of 62 control patients (17%; 95% CI 10% to 26%; P = .523). Duration of ED treatment in discharged patients was 224 +/- 75 minutes in the magnesium group (95% CI, 208 to 240 minutes) and 228 +/- 90 minutes in the control group (95% CI, 209 to 247 minutes, P = .832). In addition, changes in peak expiratory flow were not statistically different. CONCLUSION: Routine early administration of IV magnesium in acute asthma does not alter treatment outcome.