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magnesium sulfate (injection)

Generic Name: magnesium sulfate (injection) (mag NEE see um SUL fate)
Brand Name: Magnesium Sulfate-Sodium Chloride

What is magnesium sulfate injection?

Magnesium is a naturally occurring mineral that is important for many systems in the body especially the muscles and nerves.

Magnesium sulfate injection is used to treat hypomagnesemia (low levels of magnesium in your blood).

Magnesium sulfate injection is also used to prevent seizures in pregnant women with conditions such as pre-eclampsia, eclampsia, or toxemia of pregnancy.

Magnesium sulfate injection may also be used for purposes not listed in this medication guide.

What is the most important information I should know about magnesium sulfate injection?

If possible before you receive magnesium sulfate, tell your doctor if you have kidney disease, heart disease, a stomach or intestinal disorder, or if you are dehydrated. Also tell your doctor if you drink alcohol or caffeine drinks regularly, if you smoke, or if you use any street drugs.

What should I discuss with my healthcare provider before receiving magnesium sulfate injection?

Tell your doctor if you drink alcohol or caffeine drinks regularly, if you smoke, or if you use any street drugs. These factors can affect the way magnesium sulfate injection works in your body.

If possible before you receive magnesium sulfate, tell your doctor if you have:

  • kidney disease;

  • heart disease;

  • a stomach or intestinal disorder; or

  • if you are dehydrated.

You should not use magnesium sulfate if you are pregnant. It could harm the unborn baby. Use effective birth control, and tell your doctor if you become pregnant during treatment.

Magnesium sulfate can pass into breast milk and may harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.

In an emergency situation it may not be possible to tell your caregivers if you are pregnant or breast feeding. Make sure any doctor caring for your pregnancy or your baby knows you have received this medication.

How is magnesium sulfate injection given?

Magnesium sulfate is injected into a muscle or into a vein through an IV. You will receive this injection in a clinic or hospital setting.

Your breathing, blood pressure, oxygen levels, and other vital signs will be watched closely while you are receiving magnesium sulfate.

What happens if I miss a dose?

Since magnesium sulfate is given by a healthcare professional, you are not likely to miss a dose.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What should I avoid while receiving magnesium sulfate injection?

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

Magnesium sulfate injection side effects

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Tell your caregiver right away if you have:

  • feeling like you might pass out;

  • sweating, anxiety, cold feeling;

  • flushing (warmth, redness, or tingly feeling);

  • weak or shallow breathing;

  • extreme drowsiness, feeling very weak; or

  • numbness or tingly feeling around your mouth, muscle tightness or contraction, overactive reflexes.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Side Effects (complete list)

Magnesium sulfate dosing information

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)
5 grams in 1 liter of appropriate diluent IV over 3 hours
-Do not exceed IV infusion rate of 150 mg/minute

-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

-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
Maintenance dose: 1 to 2 grams/hour IV by constant infusion
-Continue therapy until paroxysms cease
Maximum dose: 30 to 40 grams/day

-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

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

Uses: Cathartic or laxative

What other drugs will affect magnesium sulfate injection?

Tell your doctor about all medicines you use, and those you start or stop using during your treatment with magnesium sulfate, especially any IV (injected) antibiotics.

Other drugs may interact with magnesium sulfate, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell each of your health care providers about all medicines you use now and any medicine you start or stop using.

Where can I get more information?

  • Your doctor or pharmacist can provide more information about magnesium sulfate.
  • Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
  • Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

Copyright 1996-2012 Cerner Multum, Inc. Version: 1.11.

Last reviewed: April 19, 2017
Date modified: December 03, 2017