Adult Dosing
Magnesium deficiency
- Mild hypomagnesemia: 1 g IM q6 hrs x 4
- Severe hypomagnesemia: 250 mg/kg IM within a period of 4 hrs PRN; alt: 5 g with 1 L D5W or NS for slow IV infusion over 3 hrs
Hyperalimentation
- In TPN, maintenance dose ranges from 1-3 g daily
Severe pre-eclampsia or eclampsia
- Initial dose: 10-14 g (4-5 g IV infusion in 250 mL D5W or NS, with up to 10 g IM divided equally in both buttocks)
- Alt: 4 g (40 mL of a 10% or 20 mL of a 20% concentration) may be injected IV over 3-4 mins with up to 4-5 g IM into alternate buttocks q4 hrs PRN
- Alt: Following the initial IV dose, administer 1-2 g/hr by constant IV until paroxysms cease
- Max: 30-40 g/24hrs
Control of seizures due to epilepsy, glomerulonephritis, or hypothyroidism
- Recommended dose: 1 g IM/IV
Paroxysmal atrial tachycardia
- Usual dose: 3-4 g IV over 30 seconds with extreme caution
Reduction of cerebral edema
- 2.5 g (25 mL of a 10% solution) IV
Ventricular tachycardia
- Initial dose: 1-6 g IV for 3-20 mg/minute for 5-48 hours depending on patient response and serum magnesium concentrations
Torsades de pointes [Not FDA approved]
- 1-2 g IV/IO PRN over 5-60 minutes, followed by an infusion of 0.5-1 g/hour
Tetanus [Non-FDA Approved]
- 40 mg/kg IV over 30 minutes, followed by 2 g/h for patients >45 kg
Note:
- Therapy should not be continued beyond 5-7 days in pregnant women due to risk of fetal harm
Pediatric Dosing
Hyperalimentation
- In TPN, maintenance dose for infants ranges from 0.25-1.25 g daily
Torsades de pointes [Not FDA approved]
- 25-50 mg/kg IV/IO PRN over several minutes
- Max: 2 g/dose
Prevention and control of seizures associated with acute nephritis in children
- 100 mg/kg IM q 4-6 h prn; Alt: 20-40 mg/kg IM PRN
- Severe symptoms: 100-200 mg/kg IV infusion; one-half the dose in 15-20 min and the total within 1 hour
- Administration of magnesium sulfate beyond 5 to 7 days to pregnant women may cause adverse outcomes in fetus such as hypocalcemia and bone abnormalities. Use in pregnancy is recommended only if absolutely required
- Use with caution in patients with impaired kidney function, especially premature neonates as this product contains aluminum that may be toxic
- Patients with renal impairment, including premature neonates who receive parenteral levels of aluminum at >4-5 mcg/kg/day accumulate aluminum at levels associated with CNS and bone toxicity
- Reserve IV use in eclampsia for immediate control of life-threatening convulsions
- Parenteral use may cause magnesium intoxication in patients with renal insufficiency
- Use with caution if flushing or sweating occurs
- Carefully adjust the dose of barbiturates, narcotics, or other hypnotics (or systemic anesthetics) when given in conjunction with magnesium
- Maintain urine output at a level of 100 mL or more during the 4 hours preceding each dose
- It is recommended to monitor serum magnesium levels and the patient’s clinical status to avoid the consequences of overdosage in toxemia
- Evaluate knee jerk reflexes before each dose when repeated doses are given parenterally; if they are absent, no additional magnesium should be given until they return
- Keep an injectable calcium salt readily available to counteract the potential hazards of magnesium intoxication in eclampsia
- Dilute magnesium sulfate injection (50%) to a concentration of 20% or less prior to IV infusion and also for IM injection in infants and children. Administer at a slow rate to avoid hypermagnesemia
Cautions: Use cautiously in:
- Renal impairment
- Nursing mothers
Pregnancy Category:A
Breastfeeding: Intravenous magnesium sulfate given before delivery might affect the infant's ability to breastfeed; however, it increases milk magnesium concentrations only slightly. Oral absorption of magnesium by the infant is poor, so maternal magnesium therapy is unlikely to affect the breastfed infant's serum magnesium. Magnesium sulfate is acceptable to use during breastfeeding. This information is based upon LactMed database (available at http://toxnet.nlm.nih.gov/cgi-bin/sis/htmlgen?LACT last accessed 22 May 2012). Manufacturer advises caution.
US Trade Name(s)
US Availability
magnesium sulfate (generic)
- INJ: 500 mg/mL (2, 10, 50 mL vials)
- INJ in 5% dextrose: 10 mg/mL (100 mL plastic container)
- INJ in 5% dextrose: 20 mg/mL (500, 1000 mL plastic container)
- INJ: 40 mg/mL (50, 100, 500 mL plastic container)
- INJ: 80 mg/mL (50 mL plastic container)
Canadian Trade Name(s)
Canadian Availability
magnesium sulfate (generic)
- INJ: 200 mg/mL
- INJ: 500 mg/mL
- INJ in 5% dextrose: 20 mg/mL (plastic container)
UK Trade Name(s)
UK Availability
magnesium sulfate (generic)
- INJ: 500 mg/mL (4 mL vials)
Australian Trade Name(s)
Australian Availability
magnesium sulfate (generic)
- INJ: 493 mg/mL (5 mL amp)
- INJ: 500 mg/mL (5, 10 mL vials)
Pricing data from www.DrugStore.com in U.S.A.
- Magnesium Sulfate 50 % SOLN [Vial] (AMERICAN REGENT)
50 % = $55.99
150 % = $159.98 - Magnesium Sulfate 50 % SOLN [Vial] (APP PHARMACEUTICAL)
100 % = $22.99
200 % = $35.97 - Magnesium Sulfate 50 % SOLN [Vial] (AMERICAN REGENT)
50 % = $37.76
150 % = $78.79
Warning: This pricing information is subject to change at the sole discretion of DS Pharmacy. For the most current and up-to-date pricing information, please visit drugstore.com.