- Mangat HS,
- D'Souza GA,
- Jacob MS
Purpose of the Study
This study investigated the efficacy of nebulized magnesium sulfate as a bronchodilator in acute asthma as compared with nebulized salbutamol.
A total of 33 patients, 12–60 years of age, with a known history of asthma participated in the study.
This was a randomized, double-blind, placebo-controlled trial. All subjects received 100 mg of intravenous hydrocortisone and were then randomized to receive 2.5 mg of salbutamol every 20 minutes for four consecutive doses, or 95 mg of 3.2% solution of magnesium sulfate also 20 minutes apart for four doses. The outcome measures included improvements in the peak expiratory flow (PEF), admission rates, and use of the Fischl index. This index takes into account the subjects' use of accessory muscles, wheezing, dyspnea, heart rate >120, respiratory rate >18, pulsus paradoxus >18, and a PEF <120. The presence of each of these signs scores 1 point and a total of more than 4 points implies severe asthma. Patients were also monitored for common adverse effects frequently associated with the use of magnesium sulfate.
Of the 16 subjects in the magnesium sulfate group, 14 showed an improvement in their Fischl index decreasing from a mean score of 4.31 pretreatment to 0.43 posttreatment. The remaining 2 subjects required supplemental therapy. One of these subjects improved and was discharged, while the other was admitted. In the control group 15 of the 17 subjects showed an improvement in their Fischl index going from a mean of 4.29 pretreatment to 0.76 posttreatment. Of the 2 subjects whose symptoms were refractory to this treatment, both required admission despite supplemental therapy. Improvement in the Fischl index pretreatment and posttreatment was statistically significant for the salbutamol and magnesium sulfate groups. There was no statistical significance in the treatment effect between groups. Comparisons of the PEF of the groups also showed an improvement, increasing 35% in the experimental group and 42% in the control group. The mean final PEF was not significantly different between the two groups. Subjects in the experimental group did not exhibit an increased incidence of the adverse effects commonly associated with magnesium sulfate.
Nebulized magnesium sulfate was found to have a clinically and statistically significant bronchodilator effect, and may well play a role as an adjunct to β2-agonists in acute asthma. The optimum dose response relationship needs to addressed in future studies.
Asthma continues to be a source of significant morbidity and mortality. This study is the first controlled clinical trial addressing the efficacy of nebulized magnesium sulfate in acute asthma, and is an important step toward identifying additional agents that can be used as adjunctive therapy. It will be important to establish the strength of the treatment effect in a larger study population and perhaps delineate the characteristics of patients most likely to benefit from the use of magnesium sulfate.