Magnesium Sulfate

Question 1

Magnesium Sulfate Class?

Answer 1

Electrolyte, anticonvulsant

Question 2

Magnesium Sulfate Action?

Answer 2

Reduces striated muscle contractions and blocks peripheral neuromuscular
transmission by reducing acetylcholine release at the myoneural junction.

Question 3

Magnesium Sulfate Indications?

Answer 3

Seizures due to eclampsia after seizure activity is stopped, torsades de pointes,
unstable V-Tach attributed to digitalis toxicity, hypomagnesemia, status asthmaticus
unresponsive to beta-adrenergic drugs

Question 4

Magnesium Sulfate Contraindications?

Answer 4

Any heart block or myocardial damage, hypotension

Question 5

Magnesium Sulfate Onset/Duration?

Answer 5

Onset: Immediate IV
Duration: 30 min IV

Question 6

Magnesium Sulfate Dose/Route?

Answer 6

Adult: Pulseless arrest (hypomagnesemia and torsades de pointes) and status
asthmaticus – 1-2 g diluted in 10 ml D5W/NS IV/IO. Torsades de pointes or
hypomagnesemia WITH A PULSE – 1-2 g in 100ml D5W/NS over 5-60 min IV. Eclampsia –
4 g IV drip over 20 min, with a max dose of 30-40 g/day

Peds: Pulseless arrest or hypomagnesemia/torsades with a pulse – 25-50 mg/kg IV/IO
(max 2 g) over 10-20 mins. Status asthmaticus - 25-50 mg/kg IV/IO (max 2 g) diluted 100
ml D5W/NS over 15-30 mins.

Question 7

Magnesium Sulfate Side Effects?

Answer 7

Hypotension, facial flushing, hyporeflexia (decreased reflexes), bradycardia,
respiratory depression, diaphoresis.

Question 8

Magnesium Sulfate Note*

Answer 8

If overdose is suspected (indicated by decreased deep tendon reflexes) may give calcium
chloride or calcium gluconate to reverse effects