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Magnesium Sulfate Dosage

Applies to the following strength(s): 50% ; 10 mg/mL-D5% ; 20 mg/mL-D5% ; 40 mg/mL-D5% ; 80 mg/mL-D5% ; 125 mg/mL ; 10 g/1000 mL ; 40 mg/mL ; 80 mg/mL ; 100 mg/mL ; 20 g/500mL-sterile water ; 40 g/1000 mL-sterile water ; 4 g/100 mL-sterile water ; 2 g/50 mL-sterile water ; 1 g/50 mL-D5% ; 2 g/50 mL-D5% ; 6 g/50 mL-D5% ; 4 g/100 mL-NaCl 0.9% ; 1 g/50 mL-NaCl 0.9% ; 1 g/100 mL-NaCl 0.9% ; 2 g/50 mL-NaCl 0.9% ; 6 g/50 mL-NaCl 0.9% ; 3 g added to NaCl 0.9% 50 mL ; 6 g added to NaCl 0.9% 100 mL ; 2 g added to D5% 50 mL ; 4 g added to D5% 100 mL ; 50 g added to LR 500 mL ; 20 g added to LR 500 mL ; 10 g added to D5% 250 mL ; 3 g added to D5% 100 mL ; 40 mg/mL-LR ; 80 mg/mL-LR ; 120 mg/mL-D5% ; 83 mg/mL-D5% ; 83 mg/mL-LR ; 1000 mg/ 50 mL-NaCl 0.9% ; 2 g/100 mL-NaCl 0.9% ; 4 g/50 mL-sterile water ; 2 g/100 mL-D5% ; 6 g/100 mL-D5%

The information at Drugs.com is not a substitute for medical advice. Always consult your doctor or pharmacist.

Usual Adult Dose for Hypomagnesemia

1 gram IM every 6 hours for 4 doses (mild hypomagnesemia) or as much as 250 mg/kg IM within a 4-hour period (severe hypomagnesemia)
OR
5 grams in 1 liter of appropriate diluent IV over 3 hours
-Do not exceed IV infusion rate of 150 mg/minute

Comments:
-Appropriate diluents include 5% dextrose or 0.9% sodium chloride.
-Use caution to prevent exceeding renal excretory capacity.
-May be given undiluted intramuscularly.
-Carefully adjust dosage to individual requirements and response.
-Discontinue as soon as the desired effect is obtained.

Usual Adult Dose for Atrial Tachycardia

3 to 4 grams (30 to 40 mL of a 10% solution) IV over 30 seconds

Comments:
-Use with EXTREME CAUTION.
-Use only if simpler methods have failed and there is no evidence of myocardial damage.

Use: Paroxysmal atrial tachycardia

Usual Adult Dose for Pre-eclampsia/Eclampsia

Severe pre-eclampsia or eclampsia:
Initial dose: 4 to 5 grams IV in 250 mL of appropriate diluent, with simultaneous IM administration of up to 5 grams (10 mL undiluted solution) in EACH buttock; total dose: 10 to 14 grams
-Initial IV dose of 4 grams may also be diluted to a 10% or 20% solution and injected IV over 3 to 4 minutes

Maintenance dose: 4 to 5 grams IM into alternate buttocks every 4 hours as needed
OR
Maintenance dose: 1 to 2 grams/hour IV by constant infusion
-Continue therapy until paroxysms cease
Maximum dose: 30 to 40 grams/day

Comments:
-Appropriate diluents include 5% dextrose or 0.9% sodium chloride.
-A serum magnesium level of 6 mg/100 mL is considered optimal for seizure control.
-The need to continue therapy is based on the continuing presence of patellar reflex and adequate respiratory function.
-Continuous maternal administration beyond 5 to 7 days can cause fetal abnormalities.
-Monitor serum magnesium and patient clinical status to avoid overdosage.
-Clinical indications of a safe dose include presence of patellar reflex (knee jerk) and absence of respiratory depression (about 16 breaths/minute or more).
-Test patellar reflex before repeat doses and do not administer magnesium if absent.
-Deep tendon reflexes begin to diminish at magnesium levels above 4 mEq/L.
-Reflexes may be absent at 10 mEq/L, where there is potential for respiratory paralysis.
-An injectable calcium salt should be immediately available to counteract magnesium intoxication.


Uses: Prevention and control of seizures in pre-eclampsia and eclampsia

Usual Adult Dose for Constipation

2 to 4 level teaspoons dissolved in 8 ounces water orally
-Repeat dose in 4 hours if needed.
Maximum dose: 2 doses per day

Uses: Cathartic or laxative

Usual Adult Dose for Barium Poisoning

1 to 2 grams IV
-Do not exceed IV infusion rate of 150 mg/minute

Use: To counteract the muscle-stimulating effects of barium poisoning

Usual Adult Dose for Seizures

1 gram intramuscularly or IV
-Do not exceed IV infusion rate of 150 mg/minute

Use: Seizures associated with epilepsy, glomerulonephritis, or hypothyroidism

Usual Adult Dose for Cerebral Edema

2.5 grams (25 mL of a 10% solution) IV
-Do not exceed IV infusion rate of 150 mg/minute

Use: Reduction of cerebral edema

Usual Pediatric Dose for Constipation

Epsom Salt:

12 years and older: 2 to 4 level teaspoons dissolved in 8 ounces water orally
6 to 11 years: 1 to 2 level teaspoons dissolved in 8 ounces of water orally
Under 6 years: Not recommended
Maximum dose: 2 doses per day

Comments:
-Repeat dose in 4 hours if needed.
-Generally produces a bowel movement in 30 minutes to 6 hours.

Uses: Cathartic or laxative

Renal Dose Adjustments

Use with caution.
-Magnesium is removed from the body solely by the kidneys.
-Parenteral use in renal insufficiency may lead to magnesium intoxication.
-Urine output should be maintained at 100 mL or more during the 4 hours preceding each dose.
-Monitoring serum magnesium and patient clinical status is essential to avoid overdose in toxemia of pregnancy.
-Reserve IV use for immediate control of life-threatening convulsions.

Prevention/Control of pre-eclamptic and eclamptic seizures:
-Maximum dosage is 20 grams/48 hours for severe renal insufficiency.
-Obtain serum magnesium concentrations frequently.
-Continuous maternal administration beyond 5 to 7 days can cause fetal abnormalities.

Liver Dose Adjustments

No adjustment recommended.

Dialysis

Data not available

Other Comments

Administration advice:
-Solutions for IV administration must be diluted to a concentration of 20% or less.
-Deep intramuscular administration of the undiluted parenteral solution is appropriate for adults.
-Dilute the parenteral solution to a concentration of 20% or less for IM administration to children.

IV compatibility:
-Compatible with 5% dextrose and 0.9% sodium chloride solutions
-The manufacturer product information should be consulted for a list of incompatible substances.

Monitoring:
-Monitor serum magnesium and patient clinical status to avoid overdosage in toxemia of pregnancy.
-Clinical indications of a safe dose include presence of patellar reflex (knee jerk) and absence of respiratory depression (about 16 breaths/minute or more).
-Test patellar reflex before repeat doses and do not administer magnesium if absent.
-Deep tendon reflexes begin to diminish at magnesium levels above 4 mEq/L.
-Reflexes may be absent at 10 mEq/L, where there is potential for respiratory paralysis.
-Serum magnesium levels of 3 to 6 mg/100 mL (2.5 to 5 mEq/L) are usually sufficient to control convulsions.
-An injectable calcium salt should be immediately available to counteract magnesium intoxication in toxemia of pregnancy.

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