Acute effect of intravenous magnesium sulfate on airway obstruction of asthmatic patients

Abstract The bronchodilating effect of magnesium sulfate (MgSO4) was studied in ten asthmatic patients with moderate to severe airway obstruction. Two grams of MgSO4 or saline in double-blind crossover design was administered IV for 20 minutes (0.40 mmol/min) and forced expiratory capacity and forced expiratory volume in one second (FEV1) were studied at intervals. Only at the end of MgSO4 infusion did FEV1 increase significantly (109% of initial values). The bronchodilating effect was short lasting and far less than that observed after salbutamol.