Magnesium Sulfate

Question 1

Magnesium Sulfate Classification

Answer 1

Electrolyte/Antidysrhythmic

Question 2

Magnesium Sulfate Mechanism

Answer 2

SMC -> Ca2+ channel blocker -> inhibits Ca2+ entry and the subsequent interaction between actin and myosin in SMC -> SMC relaxation and dilation of blood vessels and bronchial tree
Cardiac -> Ca2+ channel blocker -> negative inotropy, chronotropy, dromotropy

Question 3

Magnesium Sulfate Pharmacokinetics

Answer 3

Onset: Immediate IV, 1hr IM
Peak Effects: Varies
Duration: 1hr
Half Life: N/A

Question 4

Magnesium Sulfate Indications

Answer 4

• Severe asthma/bronchospasm
• Eclampsia
• Severe refractory VF or pulseless VT with hypo Mg2+ ; Torsades de Pointe

Question 5

Magnesium Sulfate Contraindications

Answer 5

• 3 degree heart block

- Hypotension

Question 6

Magnesium Sulfate Side effects/adverse reactions

Answer 6

Flushing, sweating, bradycardia, drowsiness, respiratory depression, dysrhythmias, hypotension, itching, rash

Question 7

Magnesium Sulfate Dose

Answer 7

Adult:
Asthma: 2g in 100cc NS IV, IO infusion over 10 min
VT, VF, Torsades - no pulse: 2g IV IO over 1-2 min
VT,Torsades + pulse: 1-2g in 50-100cc NS IV IO over 5-60 min
Eclampsia: 4g in 20cc NS IV IO over 5 min
Pedi:
Asthma: 25-50 mg/kg IV IO infusion over 15-30min, max 2gm
VT, VF, Torsades - no pulse: 25-50 mg/kg IV IO, max 2gm
VT, Torsades + pulse: 25-50 mg/kg IV IO over 10-20 min, max 2 gm

Question 8

Magnesium Sulfate Precautions

Answer 8

• Caution with impaired Renal function

- Watch for respiratory depression

Question 9

Magnesium Sulfate Drug Interactions

Answer 9

Cardiac conduction abnormalities if given with digitalis