Magnesium Sulfate
Magnesium Sulfate is an anticonvulsant used to prevent and control seizures in pregnant women with preeclampsia and eclampsia by blocking neuromuscular transmission.
Magnesium Sulfate is used to prevent and treat life-threatening seizures in women with preeclampsia and eclampsia by blocking neuromuscular transmission.
Key facts at a glance
- ATC
- A06AD04
- RxNorm
- 6585
- Generic
- Magnesium Sulfate
- Class
- atc-a06
- Brands
- Hemocyte Plus, Concept OB, Tis-U-Sol, Sutab, Ellis Tonic, Eldertonic
- Availability
- rx
- Lactation
- unknown
- Routes
- oral, topical
- Forms
- injection, prefilled syringe, capsule, solution, ointment, tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Dosage and administration
- Usual dose
- 500mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 250mg twice daily
- Maximum
- consult physician
- Frequency
- every 12 hours
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
- Usual dose
- 400mg daily
- Maximum
- consult physician
- Frequency
- once daily
- Instructions
- Follow physician instructions
- Duration limits
- as prescribed
- Monitoring
- standard
Overdose information
Special Populations
8 groupspregnancy
first trimesteravoid if possible
avoid routine use in first trimester unless clearly indicated for eclampsia treatment
regular fetal monitoring and maternal magnesium levels
Use with caution and monitor for adverse effects.
pregnancy
third trimesterstandard dosing for eclampsia
recommended for treatment and prevention of eclampsia and severe preeclampsia
continuous maternal and fetal monitoring including reflexes and respiratory rate
lactation
no adjustment typically needed
excreted in breast milk; monitor infant for diarrhea or restlessness
observe breastfed infant for symptoms of magnesium excess
Use with caution and monitor for adverse effects.
pediatric_age
infantsweight-based dosing required
use only under medical supervision for hypomagnesemia or constipation
monitor serum magnesium levels and renal function
Use with caution and monitor for adverse effects.
geriatric
elderlyreduce dose and monitor renal function
start at lower doses due to age-related decline in renal function
regular monitoring of serum magnesium and creatinine
Use with caution and monitor for adverse effects.
renal_impairment
severeavoid in severe renal failure
do not use in anuria or severe renal impairment
frequent serum magnesium monitoring essential
Use of this medication in this population requires careful consideration of risks and benefits.
renal_impairment
mild moderatereduce dose by 50% and extend dosing interval
use with caution; monitor renal function closely
frequent serum magnesium and renal function monitoring required
Use with caution and monitor for adverse effects.
hepatic_impairment
mild moderateno standard dose adjustment needed
generally safe; use standard dosing
monitor liver function tests periodically
Statistics and clinical data
Commonly prescribed since
General prescribing information for obstetric use
Drug class
Drug class information
Common uses
Common therapeutic uses
Mechanism of action
Pharmacological mechanism
Prevention of seizures in patients with preeclampsia, control of seizures in patients with eclampsia, and sometimes used as a laxative or for magnesium deficiency states.
Magnesium prevents seizures by blocking neuromuscular transmission at the motor nerve end plate and decreasing acetylcholine release, which stabilizes nerve membrane excitability and prevents the repetitive neuronal firing that causes seizures.
Requires close monitoring of reflexes, respiratory rate, urine output, and serum magnesium levels. Calcium gluconate should be readily available as an antidote for magnesium toxicity. Contraindicated in patients with heart block, severe renal impairment, or myasthenia gravis. Discontinue if respiratory depression, absent reflexes, or cardiac abnormalities occur.
Contraindications
Conditions and patient states where this medication should be avoided or used with caution.
Do not use (1)
Known allergy to this medication or its components
Use caution (1)
Consult healthcare provider for benefits vs risks assessment
Official drug label
WellAlly may earn a referral fee from linked resources at no extra cost to you. Editorial content is never influenced by commercial relationships.
This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed July 26, 2026. · Read our editorial policy