Magnesium Sulfate

Category:

Nervous System

Description:

Antiarrhythmic, uterine relaxant, electrolyte supplement

Indications:

Hypomagnesemia
Eclampsia prophylaxis
Preterm labor (non FDA approved)

Contraindications:

Renal failure, hypermagnesemia; appendicitis, bowel obstruction/perforation
Patients with heart block or myocardial damage

Precautions:

Pregnancy category B
Diarrhea, digitalized patients, impaired renal function

Adverse Reactions (Side Effects):

CNS: coma, depressed deep tendon reflexes, lethargy, weakness
CV: decreased BP, heart block, increased pulse
METAB: hypermagnesemia
RESP: respiratory distress

Dosage:

Administered parenterally

Adult:
- IM 4-5g of 50% solution every 4 hours as needed
- IV 4g of a 10%-20% solution initially then 4-5g in 250ml of D5W or NS at a rate not exceeding 3 ml/min by infusion (pre-eclampsia)
- IM/IV 1g every 6 hours for 4 doses; for severe deficiency, 8-12g daily in divided doses (hypomagnesemia); PO 10-15g in a glass of water (laxative)
Child:
- Neonate IV 25-50 mg/kg/dose every 8-12 hours for 2-3 doses
- child
  - IM/IV 25-50 mg/kg/dose every 4-6 hours for 3-4 doses, max single dose 2000mg (hypomagnesemia);
  - PO 5-10g in a glass of water (laxative)

Source: Operational Medicine 2001, Health Care in Military Settings, NAVMED P-5139, May 1, 2001, Bureau of Medicine and Surgery, Department of the Navy, 2300 E Street NW, Washington, D.C., 20372-5300