RESUMO
Recently magnesium sulphate (MgSO4) has been used as a bronchodilator in adults with asthma not responding favourably to conventional bronchodilator therapy (CBT). In our institution we treated severe asthmatics with continuous infusion of MgSO4 when everything else failed. However, the optimal dose and frequency to maintain adequate magnesium levels for sustained bronchodilation is not known. The objective of this study was to examine the effect of a continuous infusion of MgSO4 on serum magnesium (Mg) levels, Woods Clinical Asthma Scores (CAS) and side effects in severe asthmatics on standard therapy. Six patients were treated with continuous MgSO4 after they did not respond to CBT. All patients received an initial loading dose of MgSO4 (60-70 mg/kg) during 20 minutes, followed by a continuous infusion of 2-3 g/hr (28-52 mg/kg/hr). Patient data included: Woods Clinical Asthma Score (CAS); Mg levels at baseline (0 min), 40 min and 4 hr after starting the loading dose; electrolytes and ionizing calcium at 4 hr. Patients were monitored continuously for evidence of untoward effect (blood pressure, heart rate and rhythm, deep tendon reflexes). All patients showed sustained clinical improvement. MgS04 may be a beneficial adjunctive therapy for severe asthma. A continuous infusion may maintain adequate levels for sustained bronchodilation with no side effect.(AU)
