Classes
DEA Class; Rx
Common Brand Names; MgSO4
- Antidysrhythmics, V;
- Electrolytes
Description
Depresses CNS, blocks peripheral neuromuscular transmission, produces anticonvulsant effects; decreases amount of acetylcholine released at end-plate by motor nerve impulse
Slows rate of SA node impulse formation in myocardium and prolongs conduction time
Promotes movement of calcium, potassium, and sodium in and out of cells and stabilizes excitable membranes
Promotes osmotic retention of fluid in colon, causing distention and increased peristaltic activity, which subsequently results in bowel evacuation
Indications
Indicated for the treatment of Hypomagnesemia, Torsades de Pointes
Indicated to prevent seizures associated with pre-eclampsia, and for control of seizures with eclampsia
Used as a tocolytic to stop preterm labor
Contraindications
Hypersensitivity
Myocardial damage, diabetic coma, heart block
Hypermagnesemia
Hypercalcemia
Administration during 2 hours preceding delivery for mothers with toxemia of pregnancy
Adverse Effects
- Circulatory collapse
- Respiratory paralysis
- Hypothermia
- Pulmonary edema
- Depressed reflexes
- Hypotension
- Flushing
- Drowsiness
- Depressed cardiac function
- Diaphoresis
- Hypocalcemia
- Hypophosphatemia
- Hyperkalemia
- Visual changes
Warnings
Fetal skeletal demineralization, hypocalcemia, and hypermagnesemia abnormalities reported with continuous long-term use (ie, longer than 5-7 days) for off-label treatment of preterm labor in pregnant women; the effect on the developing fetus may result in neonates with skeletal abnormalities
In patients with renal impairment, ensure that renal excretory capacity is not exceeded
Use with caution in digitalized patients
Use with extreme caution in patients with myasthenia gravis or other neuromuscular disease
Hypomagnesemia is usually associated with hypokalemia (potassium levels must be normalized)
Monitor renal function, blood pressure, respiratory rate, and deep tendon reflex when magnesium sulfate is administered parenterally
Pregnancy and Lactation
Pregnancy category: D
Fetal skeletal demineralization, hypocalcemia, and hypermagnesemia reported with continuous long-term use (ie, longer than 5-7 days) for off-label treatment of preterm labor in pregnant women; the effect on the developing fetus may result in neonates with skeletal abnormalities
Continuous administration of magnesium sulfate injection to treat preterm labor is not approved and that the safety and efficacy of use for this indication are not established
Lactation: Safe
Maximum Dosage
Mild: 1 g IM q6hr for 4 doses
Severe
- Asymptomatic: 4-8 g at ≤1 g/hr
- Symptomatic: 4-8 g at ≤4 g over 4-5 min
4-5 g (diluted in 250 mL NS/D5W) IV in combination with either (a) up to 10 g (20 mL of undiluted 50% solution) divided and administered IM into each buttock or (b) after initial IV dose, 1-2 g/hr IV; may administer q4hr as necessary
How supplied
Magnesium Sulfate
injectable solution
- 40mg/mL
- 80mg/mL
- 50%
infusion solution
- 1g/100mL
- 2g/100mL