The Effects of Magnesium Sulfate:
- Sometimes nicknamed Mag Sulfate
- Affects the SA node by slowing down its impulse rate
- Reduces the automaticity in partially depolarized cells
- Causes vasodilation
- When given rapidly, may create hypotension
Indications for Use of Magnesium Sulfate:
Magnesium sulfate is effective as an anticonvulsant and an antiarrhythmic.
It is used to treat polymorphic ventricular tachycardia with a pulse. It is only recommended for use in cardiac arrest if Torsades de pointes or suspected hypomagnesemia is present. Magnesium sulfate is also indicated for life-threatening ventricular arrhythmias due to digitalis toxicity.
Magnesium Sulfate Precautions & Contraindications:
Routine administration of magnesium sulfate in hospitalized patients with acute myocardial infarction is not recommended. Magnesium sulfate is contraindicated for patients with central nervous system (CNS) depression or hypermagnesemia.
Caution needs to be used in patients with renal impairment.
Adult Dosage for Magnesium Sulfate:
Dosage for pulseless cardiac arrest:
- 1-2 g or 2 to 4 mL of a 50% solution diluted in 10mL D5W (5% dextrose in water) or normal saline
- IV/IO push over 5-20 minutes
Dosage for Torsades de pointes with a pulse or acute myocardial infarction (AMI) with hypomagnesemia:
- Loading dose of 1 to 2 g mixed in 50 to 100 mL of D5W or Normal Saline
- Give via IV over 5 to 60 minutes
- Follow with .5 to 1 g per hour IV titrated to control Torsades de pointes