Page 144 - 2026 SMOG

MAGNESIUM SULFATE
Class/Mechanism of Action
• Anticonvulsant, Electrolyte Supplement
IV magnesium decreases acetylcholine in motor nerve terminals, slows the rate of SA node
impulse formation, and prolongs conduction time. Magnesium functions to facilitate the
movement of calcium, sodium, and potassium in and out of cells.
Indications
• Labeled Indications
˚ Prevention and treatment of seizures in pregnancies with severe preeclampsia or eclampsia
• Off-Label Indication
˚ Torsades de Pointes: Cardiac arrhythmias (VT/VF) caused by low serum magnesium
Contraindications
• Hypersensitivity to any component of the formulation
• Myocardial damage and heart blocks
• IV use for preeclampsia/eclampsia during a 2-hr period before delivery
Adverse Reactions/Precautions
• Possible cardiovascular arrest, respiratory depression, and hypotension in large doses
• Hypomagnesemia is often accompanied by hypokalemia and requires correction to normalize
potassium.
• Magnesium Sulfate should be diluted into 50–100mL NS or D5W for all adult and
pediatric infusions.
• Pediatrics: Rapid infusion may cause hypotension or bradycardia. Have calcium chloride
available to reverse magnesium toxicity if it occurs.
• Pregnancy: Category D
• Lactation: Use caution
Dose/Administration
PEDIATRIC
ADULT
(Always reference Broselow Tape)
Torsades de Pointes or VF/Pulseless VT Pulseless Torsades de Pointes
Associated with Torsades de Pointes • IV/IO
(Off-Label use) ˚ 25–50mg/kg bolus (max dose: 2g)
• IV/IO Status Asthmaticus
˚ 1–2g over 15min. If no response or • IV/IO
Torsades de Pointes recurs, may repeat
dose to a total of 4g in 1hr ˚ 25–50mg/kg over 15–30min
(max dose: 2g)
Wheezing in Respiratory Distress Hypomagnesemia
(3rd line drug) • IV/IO
• IV ˚ 25–50mg/kg over 10–20min
˚ 2g single dose over 20min Eclampsia/ (max dose: 2g)
Pre-Eclampsia, Severe (Off-Label use)
• IV
˚ 4–6g over 15–30min followed by 1–2g/hr
continuous infusion for 24hr

136 • MEDICATIONS