Effect of Parenteral Magnesium Sulfate on Pulmonary Functions in Bronchial Asthma

Abstract

Eighteen patients with bronchial asthma were studied in a single-blind fashion. Each patient received an infusion of magnesium sulfate (MgSO₄·7H₂O 50% W/V) in a dose equivalent to 10 mmol of elemental magnesium. The airways resistance showed a significant decrease (p < 0.01) while SGaw increased significantly (p < 0.001) with MgSO₄ infusion. FEV₁ (p < 0.01), FEF_25–75% (p < 0.05), and V₅₀ (p < 0.05) also showed statistically significant increase (p < 0.001) with MgSO₄ infusion. Significant changes in Raw (p < 0.01) and SGaw (p < 0.01) persisted at 10 and 20 min following MgSO₄ infusion. No significant side effects were observed with MgSO₄ infusion. It is concluded that modest improvement in airways resistance and specific conductance and only small improvement in maximal expiratory flow rates is consistent with a predominant effect of MgSO₄ on large airways in patients with bronchial asthma.