Magnesium Sulfate

Question 1

Magnesium Sulfate
Classification

Answer 1

Electrolyte
Antidysrhythmic

Question 2

Magnesium Sulfate
Mechanism of Action

Answer 2

-SMC Ca channel blocker: inhibits calcium entry and the subsequent interaction between actin and myosin in smooth muscle cells which leads to smooth muscle relaxation and dilation of blood vessels and bronchial tree
-Cardiac Ca channel blocker: negative chronotropy, inotropy, dromotropy

Question 3

Magnesium Sulfate
Onset of Action

Answer 3

Immediate IV
1 hr IM

Question 4

Magnesium Sulfate
Peak Effects

Answer 4

Varies

Question 5

Magnesium Sulfate
Duration of Effect

Answer 5

1 hr

Question 6

Magnesium Sulfate
Half-life

Answer 6

N/A

Question 7

Magnesium Sulfate
Indications/Field Use

Answer 7

Severe Asthma/Bronchospasm
Severe refractory VF or pulseless VT w/hypomag
Torsades de Pointes
Eclampsia

Question 8

Magnesium Sulfate
Contraindications

Answer 8

3 degree heart block
hypotension

Question 9

Magnesium Sulfate
Side Effects/Adverse Reactions

Answer 9

Flushing
Sweating
Bradycardia
Drowsiness
Respiratory Depression
Dysrhythmias
Hypotension
Itching
Rash

Question 10

Magnesium Sulfate
Adult Dose

Answer 10

Asthma 2g in 100cc NS IV/IO infusion over 10 min
VT/VF/Tor (no pulse) 2g IV/IO over 1-2 min
VT/Tor (pulse) 1-2g in 50-100cc NS IV/IO over 5-60 min
Eclampsia 4g in 20ml IV/IO ober 5 min

Question 11

Magnesium Sulfate
Pedi Dose

Answer 11

Asthma 40mg/kg IV/IO in 100cc over 20min (max 2g)
VT/Tor (no pulse) 25-50mg/kg IV/IO (max 2g)
VT/Tor (pulse) 25-50mg/kg IV/IO over 10-20min (max 2g)

Question 12

Magnesium Sulfate
Precautions

Answer 12

Caution with impaired renal function
Watch for respiratory depression

Question 13

Magnesium Sulfate
Drug-drug Interactions

Answer 13

Cardiac conduction abnormalities if given with digitalis