magnesium sulfate (injection)

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: Jerry R. Balentine, DO, FACEP
    Jerry R. Balentine, DO, FACEP

    Jerry R. Balentine, DO, FACEP

    Dr. Balentine received his undergraduate degree from McDaniel College in Westminster, Maryland. He attended medical school at the Philadelphia College of Osteopathic Medicine graduating in1983. He completed his internship at St. Joseph's Hospital in Philadelphia and his Emergency Medicine residency at Lincoln Medical and Mental Health Center in the Bronx, where he served as chief resident.

What is magnesium sulfate-injection, and how does it work (mechanism of action)?

Magnesium sulfate is a sterile solution of magnesium sulfate heptahydrate in water for injection. Magnesium sulfate prevents convulsions by blocking transmission between nerves and muscles. It also reduces the amount of t acetylcholine, a chemical that nerves use for communicating with other nerves and tissues.

What brand names are available for magnesium sulfate-injection?


Is magnesium sulfate-injection available as a generic drug?


Do I need a prescription for magnesium sulfate-injection?


What are the side effects of magnesium sulfate-injection?

Side effects of magnesium sulfate are:

What is the dosage for magnesium sulfate-injection?


Which drugs or supplements interact with magnesium sulfate-injection?

Barbiturates, narcotics or other hypnotics or other drugs that slow brain function may add to the brain depressing effects of magnesium. Magnesium adds to the effect of neuromuscular blocking agents.

Magnesium sulfate should be administered with extreme caution in patients receiving digoxin (Lanoxin) due to the risk of abnormal heart beats.

Is magnesium sulfate-injection safe to take if I'm pregnant or breastfeeding?

Magnesium sulfate can cause fetal abnormalities, such as hypocalcemia, skeletal demineralization, osteopenia and other skeletal abnormalities, when administered beyond 5-7 days to pregnant women. It should be used only if clearly needed. If magnesium sulfate needs to be used during pregnancy, the woman should be informed of the potential risks to the newborn.

Magnesium sulfate enters breast milk therefore, it is best to be cautious before using it in nursing mothers.

What else should I know about magnesium sulfate-injection?

What preparations of magnesium sulfate-injection are available?

Intramuscular magnesium sulfate available in 500 mg/ml strength, in 2 ml, 10 ml, and 50 ml single-use vials.

Intravenous magnesium sulfate is available in 40mg/ml and 80mg/ml strengths. 40 mg/ml concentration is available in 50 ml, 100 ml, 500 ml, and 1000 ml single-dose, plastic containers. 80 mg/ml concentration is available in 50 ml partial-fill, single-dose, flexible plastic container.

How should I keep magnesium sulfate-injection stored?

Intramuscular magnesium sulfate injections are stored between 15 C to 30 C (59 F to 86 F). Intravenous magnesium sulfate injections are stored between 20 C to 25 C (68 F to 77 F).


Magnesium sulfate is a sterile solution given by injection prescribed for seizures with pre-eclampsia and eclampsia, eclampsia; Torsades de Pointes, an abnormal heart rhythm; and hypomagnesemia. Side effects, drug interactions, warnings and precautions, and dosage information should be reviewed prior to taking this medication.

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FDA Prescribing Information.

Medscape. magnesium sulfate (Rx).