Recommended Magnesium Sulfate Dosing for Pediatric Asthma
For pediatric patients with severe refractory asthma not responding to conventional therapy, the recommended dose of IV magnesium sulfate is 50 mg/kg (maximum 2 grams) administered over 20 minutes. 1
Indications for Use
Magnesium sulfate should be used in pediatric patients with:
- Life-threatening asthma exacerbations
- Severe exacerbations that remain unresponsive after 1 hour of intensive conventional treatment (including inhaled β-agonists and systemic corticosteroids) 1
- FEV1 or PEF < 40% predicted after initial treatment
Administration Methods
Two evidence-based administration options exist:
Standard bolus dosing: 50 mg/kg (maximum 2 grams) administered over 20 minutes 1
Continuous infusion protocol: 50 mg/kg/hour for 4 hours (maximum 8 grams total) for severe cases 2, 3
- This high-dose prolonged infusion has shown significant benefits in reducing hospital length of stay and facilitating earlier discharge
Clinical Benefits
IV magnesium sulfate provides several important clinical benefits:
- Relaxes bronchial smooth muscle independent of serum magnesium level 1
- Improves pulmonary function and reduces hospital admissions 1
- Shows early and significant improvement in peak expiratory flow rate (PEFR) and oxygen saturation 4
- Has minimal side effects (primarily flushing and light-headedness) 1
Monitoring
During administration, monitor for:
- Respiratory status improvement
- Vital signs
- Rare side effects including hypotension
- Serum magnesium levels are not routinely required unless renal impairment is present
Contraindications
Magnesium sulfate should be avoided in patients with:
- Renal failure
- Atrioventricular block
- Hypotension
- Hypermagnesemia
Recent research demonstrates that IV magnesium sulfate is effective and safe in children with severe acute asthma, with a number needed to treat of just 2.7 patients to facilitate discharge within 24 hours when using the continuous infusion protocol 3, 5.