From the Research
The recommended dose of magnesium sulfate (MgSO4) for pediatric asthma management is 40-50 mg/kg, administered as a single intravenous infusion over 60 minutes, with a maximum dose of 1,500 mg for patients over 30 kg. This dose is based on the most recent and highest quality study available, which demonstrated significant improvement in lung function parameters in children with acute asthma 1. The study found that administration of IV MgSO4 was associated with improved pulmonary function in children with acute asthma, with few side effects.
When administering MgSO4, it is essential to monitor the patient for potential side effects, including hypotension, flushing, and respiratory depression. Cardiac monitoring should be in place during administration, particularly in patients with renal impairment, as they may be at higher risk for magnesium toxicity. Magnesium sulfate works by causing bronchial smooth muscle relaxation through calcium channel blockade, helping to reduce airway constriction.
While not a first-line therapy, magnesium sulfate can be an effective adjunct treatment for children with severe asthma exacerbations to help prevent intubation and mechanical ventilation. The medication should be reserved for moderate to severe asthma exacerbations that have not adequately responded to first-line treatments, such as inhaled beta-agonists, anticholinergics, and systemic corticosteroids.
Key points to consider when using MgSO4 in pediatric asthma management include:
- Dose: 40-50 mg/kg, maximum 1,500 mg for patients over 30 kg
- Administration: single intravenous infusion over 60 minutes
- Monitoring: cardiac monitoring, potential side effects (hypotension, flushing, respiratory depression)
- Indications: moderate to severe asthma exacerbations, adjunct treatment to first-line therapies.