Drug Summary

Magnesium Sulfate

Pharmacologic properties:

Magnesium is a cation that acts as a cofactor of the cellular membrane sodium-potassium pump, and plays an integral role in maintaining intracellular potassium levels. Magnesium is essential for energy transfer and electrical stability, and acts as a powerful antiarrhythmic - particularly in the setting of torsades de pointes. It is also a CNS depressant effective in the management of seizures associated with toxemia of pregnancy (eclampsia), and a bronchodilator effective for asthma and COPD.


  • Cardiac Arrest associated with suspected hypomagnesemic state
  • Torsades de Pointes
  • Eclampsia
  • Known hypomagnesemia associated with arrhythmias
  • Bronchospasm (wheezing) unresponsive to albuterol and ipratropium bromide


  • Renal Failure


  • Avoid rapid IVP unless unstable
  • May induce respiratory depression or apnea - in this setting, treat with 10% calcium chloride, 5-10 mL IV bolus
  • Use with extreme caution in patients with myasthenia gravis, neuromuscular disease, or heart block

Adverse Reactions:

  • Loss of deep tendon reflexes
  • Respiratory arrest
  • Hypotension
  • Drowsiness
  • Flushing

Dosage and administration:

  • Adult
    • Cardiac arrest ( in the setting of torsades de pointes or hypomagnesemic state):
      • 2 grams, IV/IO bolus over 1-2 minutes
    • Eclampsia:
      • 4 grams IV over 10 minutes
    • Bronchospasm:
      • 2 grams IV over 10-15 minutes
  • Pediatric
    • Cardiac Arrest (in the setting of torsades de pointes or hypomagnesemic state):
      • 50 mg/kg IV/IO over 1-2 minutes (maximum dose 2 grams)
    • Bronchospasm:
      • 50 mg/kg IV over 10-15 minutes (maximum dose 2 grams)