Lack of effectiveness of magnesium in chronic stable asthma. A prospective, randomized, double-blind, placebo-controlled, crossover trial in normal subjects and in patients with chronic stable asthma.
BACKGROUND
Magnesium sulfate has been helpful in the treatment of acute exacerbations of asthma. We hypothesized that magnesium would also be an effective bronchodilator in patients with chronic stable asthma.


METHODS
We performed a prospective, randomized, double-blind, placebo-controlled, crossover trial in 15 patients with chronic, stable asthma and 10 nonasthmatics. On study day 1, spirometry and albuterol challenge were used to confirm the presence of asthma according to American Thoracic Society criteria. On study day 2, subjects received intravenous magnesium sulfate (2 g) or placebo (saline). On study day 3, subjects were crossed over to receive the other drug. Spirometry was performed before, during, and after drug or placebo administration. Circulating ionized magnesium concentrations were determined before and after intravenous magnesium or placebo administration.


RESULTS
Magnesium infusion caused no statistically significant changes in forced expiratory volume in 1 second (mean +/- SEM, 1.92 +/- 0.13 L before, 1.98 +/- 0.12 L during, and 2.01 +/- 0.14 L after magnesium administration), forced vital capacity (mean +/- SEM, 3.44 +/- 0.25 L before, 3.60 +/- 0.26 L during, and 3.59 +/- 0.25 L after magnesium administration), or maximum forced expiratory flow rate (mean +/- SEM, 5.42 +/- 0.44 L/second before, 5.46 +/- 0.46 L/second during, and 5.57 +/- 0.49 L/second after magnesium administration). Placebo caused no changes in these three physiologic variables.


CONCLUSIONS
Magnesium is not effective as a bronchodilator in chronic, stable asthmatics or in normal non-asthmatic adults.
Bernstein
W K
WK
Department of Medicine, Sinai Hospital of Baltimore, Md.
Khastgir
T
T
Khastgir
A
A
Hernandez
E
E
Miller
J
J
Schonfeld
S A
SA
Nissim
J E
JE
Chernow
B
B
D000328:Adult; D001249:Asthma / Q000097:blood / Q000188:drug therapy* / Q000503:physiopathology; D002908:Chronic Disease; D004311:Double-Blind Method; D005260:Female; D006801:Humans; D008278:Magnesium Sulfate / Q000627:therapeutic use*; D008297:Male; D011446:Prospective Studies; D012129:Respiratory Function Tests; D017211:Treatment Failure
D008278:Magnesium Sulfate