Magnesium sulfate

What is Magnesium sulfate?

• Magnesium sulfate is a sterile solution of magnesium sulfate heptahydrate in Water for Injection, administered by the intravenous or intramuscular routes as an electrolyte replenisher or anticonvulsant.

Magnesium Sulfate (1)

Magnesium sulfate

Magnesium sulfate

What are the uses of this medicine?

Magnesium sulfate is used:

• for replacement therapy in magnesium deficiency, especially in acute hypomagnesemia.
• In total parenteral nutrition (TPN), magnesium sulfate may be added to the nutrient admixture to correct or prevent hypomagnesemia.
• for the prevention and control of seizures (convulsions) in pre-eclampsia and eclampsia, respectively.

How does this medicine work?

• Magnesium (Mg++) is an important cofactor for enzymatic reactions and plays an important role in neurochemical transmission and muscular excitability.
• As a nutritional adjunct in hyperalimentation, the precise mechanism of action for magnesium is uncertain.
• Predominant deficiency effects are neurological, e.g., muscle irritability, clonic twitching and tremors.
• Hypocalcemia and hypokalemia often follow low serum levels of magnesium.
• While there are large stores of magnesium present intracellularly and in the bones of adults, these stores often are not mobilized sufficiently to maintain plasma levels. Parenteral magnesium therapy repairs the plasma deficit and causes deficiency symptoms and signs to cease.
• Magnesium prevents or controls convulsions by blocking neuromuscular transmission and decreasing the amount of acetylcholine liberated at the end plate by the motor nerve impulse.
• Magnesium is said to have a depressant effect on the central nervous system (CNS), but it does not adversely affect the woman, fetus or neonate when used as directed in eclampsia or pre-eclampsia.
• Magnesium acts peripherally to produce vasodilation.
• With low doses only flushing and sweating occur, but larger doses cause lowering of blood pressure.
• The central and peripheral effects of magnesium poisoning are antagonized to some extent by intravenous administration of calcium.

Who Should Not Use this medicine ?

This medicine cannot be used in patients:

• with heart block or myocardial damage.

What drug interactions can this medicine cause?

• Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.

Be sure to mention any of the following:

• barbiturates
• narcotics or other hypnotics (or systemic anesthetics)
• other CNS depressants
• Neuromuscular Blocking Agents
• Cardiac Glycosides

Is this medicine FDA approved?

• Magnesium sulfate came into medical use at least as early as 1618.
• It is on the World Health Organization's List of Essential Medicines.

How should this medicine be used?

Recommended dosage: In Magnesium Deficiency:

• In the treatment of mild magnesium deficiency, the usual adult dose is 1 gram, equivalent to 8.12 mEq of magnesium (2 mL of the 50% solution) injected intramuscularly every six hours for four doses (equivalent to a total of 32.5 mEq of magnesium per 24 hours).
• For severe hypomagnesemia, as much as 250 mg (approximately 2 mEq) per kg of body weight (0.5 mL of the 50% solution) may be given intramuscularly within a period of four hours if necessary.
• Alternatively, 5 grams, (approximately 40 mEq) can be added to one liter of 5% Dextrose Injection, USP or 0.9% Sodium Chloride Injection, USP for slow intravenous infusion over a three-hour period.

In Hyperalimentation:

• Maintenance requirements for magnesium are not precisely known.
• The maintenance dose used in adults ranges from 8 to 24 mEq (1 gram to 3 grams) daily.
• For infants, the range is 2 to 10 mEq (0.25 gram to 1.25 grams) daily.

In Pre-eclampsia or Eclampsia:

• In severe pre-eclampsia or eclampsia, the total initial dose is 10 grams to 14 grams of magnesium sulfate.
• Therapy should continue until paroxysms cease. A serum magnesium level of 6 mg/100 mL is considered optimal for control of seizures.
• A total daily dose of 30 grams to 40 grams should not be exceeded.
• In the presence of severe renal insufficiency, the maximum dosage of magnesium sulfate is 20 grams/48 hours and frequent serum magnesium concentrations must be obtained.
• Continuous use of magnesium sulfate in pregnancy beyond 5 to 7 days can cause fetal abnormalities.

Other Uses:

• In counteracting the muscle-stimulating effects of barium poisoning, the usual dose of magnesium sulfate is 1 gram to 2 grams given intravenously.
• For controlling seizures associated with epilepsy, glomerulonephritis or hypothyroidism, the usual adult dose is 1 gram administered intramuscularly or intravenously.
• In paroxysmal atrial tachycardia, magnesium should be used only if simpler measures have failed and there is no evidence of myocardial damage. The usual dose is 3 grams to 4 grams (30 to 40 mL of a 10% solution) administered intravenously over 30 seconds with extreme caution.
• For reduction of cerebral edema, 2.5 grams (25 mL of a 10% solution) is given intravenously.

What are the dosage forms and brand names of this medicine?

This medicine is available in fallowing doasage form:

• As Magnesium Sulfate Injection, USP 50% is a sterile solution of magnesium sulfate heptahydrate in Water for Injection

This medicine is available in fallowing brand namesː

• Sulfamag

What side effects can this medication cause?

The most common side effects of this medicine include:

• flushing, sweating, hypotension, depressed reflexes, flaccid paralysis, hypothermia, circulatory collapse, cardiac and central nervous system depression proceeding to respiratory paralysis.

• Hypocalcemia with signs of tetany secondary to magnesium sulfate therapy for eclampsia has been reported.

What special precautions should I follow?

• Continuous administration of magnesium sulfate beyond 5 to 7 days to pregnant women can lead to hypocalcemia and bone abnormalities in the developing fetus. If magnesium sulfate is given for treatment of preterm labor, the woman should be informed that the efficacy and safety of such use have not been established and that use of magnesium sulfate beyond 5 to 7 days may cause fetal abnormalities.
• This product contains aluminum that may be toxic. Aluminum may reach toxic levels with prolonged parenteral administration if kidney function is impaired. Premature neonates are particularly at risk because their kidneys are immature, and they require large amounts of calcium and phosphate solutions, which contain aluminum.
• Parenteral use in the presence of renal insufficiency may lead to magnesium intoxication. Intravenous use in the eclampsia should be reserved for immediate control of life-threatening convulsions.
• Administer with caution if flushing and sweating occurs. When barbiturates, narcotics or other hypnotics (or systemic anesthetics) are to be given in conjunction with magnesium, their dosage should be adjusted with caution because of additive CNS depressant effects of magnesium.
• Because magnesium is removed from the body solely by the kidneys, the drug should be used with caution in patients with renal impairment.
• Magnesium sulfate injection should not be given unless hypomagnesemia has been confirmed and the serum concentration of magnesium is monitored. The normal serum level is 1.5 to 2.5 mEq/L.
• Continuous administration of magnesium sulfate is an unapproved treatment for preterm labor. The safety and efficacy of such use have not been established.
• Since magnesium is distributed into milk during parenteral magnesium sulfate administration, the drug should be used with caution in nursing women.

What to do in case of emergency/overdose?

Symptoms of overdose may include:

• sharp drop in blood pressure and respiratory paralysis

Management of overdosage:

• In case of overdose, call the poison control helpline of your country. In the United States, call 1-800-222-1222.

• Overdose related information is also available online at poisonhelp.org/help.
• In the event that the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services. In the United States, call 911.
• Disappearance of the patellar reflex is a useful clinical sign to detect the onset of magnesium intoxication.
• In the event of overdosage, artificial ventilation must be provided until a calcium salt can be injected intravenously to antagonize the effects of magnesium.
• Artificial respiration is often required.
• Intravenous calcium, 10 to 20 mL of a 5% solution (diluted if desirable with isotonic sodium chloride for injection) is used to counteract effects of hypermagnesemia.
• Subcutaneous physostigmine, 0.5 to 1 mg may be helpful.
• Hypermagnesemia in the newborn may require resuscitation and assisted ventilation via endotracheal intubation or intermittent positive pressure ventilation as well as intravenous calcium.

Can this medicine be used in pregnancy?

• Magnesium sulfate can cause fetal abnormalities when administered beyond 5 to 7 days to pregnant women.
• Magnesium sulfate injection should be used during pregnancy only if clearly needed.
• If this drug is used during pregnancy, the woman should be apprised of the potential harm to the fetus.

What are the active and inactive ingredients in this medicine?

Active ingredient:

• MAGNESIUM SULFATE HEPTAHYDRATE

Inactive ingredients:

• WATER
• SULFURIC ACID
• SODIUM HYDROXIDE

Who manufactures and distributes this medicine?

• Distributed by Hospira, Inc., Lake Forest, IL USA

What should I know about storage and disposal of this medication?

• Store at 20°C to 25°C (68°F to 77°F); excursions permitted between 15°C and 30°C (59°F and 86°F).

• Dailymed label info on Magnesium sulfate
• FDA Magnesium sulfate

Magnesium sulfate Resources
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