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)