Intravenous Magnesium Sulfate in Acute Asthma

To the Editor.— I have several comments concerning the article entitled "Intravenous Magnesium Sulfate for the Treatment of Acute Asthma in the Emergency Department."¹The authors contend that "conventional nebulized β-agonist therapy has met with disappointing results in an increasing number of moderate to severe asthmatics who may be characterized as 'poor responders'" and reference studies that utilize prior protocols that emphasize subcutaneous β-agonist therapy and hourly inhaled β-agonists in addition to intravenous aminophylline and hydrocortisone therapy.²,³They demonstrate that administration of intravenous magnesium results in a significant bronchodilatory effect and suggest its possible role in poor responders to inhaled β-agonist therapy. The fact that approximately 30% of asthmatics require admission to the hospital does not necessarily imply failure of the bronchodilator and the need for an alternative therapy but rather may represent the coexistent mucosal edema and secretions that a β-agonist would not be expected to treat