Magnesium Sulfate 50% Inj, 50ml
It is used to treat or prevent low magnesium levels.It is used to prevent and control seizures during pregnancy.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Anticonvulsant; Electrolyte Supplement; Tocolytic
Pharmacologic Class
Mineral; CNS Depressant; Smooth Muscle Relaxant
Pregnancy Category
Category D
FDA Approved
Jan 1970
DEA Schedule
Not Controlled
Overview
What is this medicine?
Magnesium sulfate is a mineral given by injection to treat low magnesium levels, prevent seizures in pregnant women with preeclampsia or eclampsia, and sometimes to treat severe asthma attacks or certain heart rhythm problems. It works by relaxing muscles and calming the nervous system.
How to Use This Medicine
Taking Your Medication
To use this medication correctly, follow your doctor's instructions and read all the information provided. It's essential to follow the instructions carefully. This medication is administered either as an injection into a muscle or as an infusion into a vein, which is given over a period of time.
Storing and Disposing of Your Medication
If you need to store this medication at home, consult with your doctor, nurse, or pharmacist to determine the best way to store it.
Missing a Dose
If you miss a dose, contact your doctor to find out what steps to take next.
To use this medication correctly, follow your doctor's instructions and read all the information provided. It's essential to follow the instructions carefully. This medication is administered either as an injection into a muscle or as an infusion into a vein, which is given over a period of time.
Storing and Disposing of Your Medication
If you need to store this medication at home, consult with your doctor, nurse, or pharmacist to determine the best way to store it.
Missing a Dose
If you miss a dose, contact your doctor to find out what steps to take next.
Lifestyle & Tips
- Report any unusual symptoms immediately, especially difficulty breathing, muscle weakness, or feeling very sleepy.
- Inform healthcare providers about all medications you are taking, including over-the-counter drugs and supplements.
- Avoid alcohol and other sedatives while receiving magnesium sulfate, as they can increase drowsiness and breathing problems.
Available Forms & Alternatives
Available Strengths:
- Magnesium Oxide 400mg Tablets
- Magnesium Sulfate 50% Inj, 10ml
- Magnesium 500mg Tablets
- Magnesium Sulfate 40mg/ml Inj, 50ml
- Magnesium Chloride 20% Inj, 50ml
- Magnesium Sulf 40mg/ml Inj, 100ml
- Magnesium Sulfate 50% Inj, 50ml
- Magnesium 200mg Tablets
- Magnesium Sulfate 50% Inj, 2ml
- Magnesium 300mg Capsules
- Magnesium Sulfate 40mg/ml Inj, 50ml
- Magnesium Sulfate 80mg/ml Inj, 50ml
- Magnesium 250mg Tablets
- Magnesium Sulfate 80mg/ml Inj
- Magn Sulf/d5w 10mg/ml Inj, 100ml
- Magnesium Oxide 250mg Tablets
- Magnesium Citrate Soln Lemon 296ml
- Magnesium Sulfate 50% Inj, 20ml
- Magnesium Su 40g/1000ml Inj, 1000ml
- Magnesium Sulfate 20gm/500ml Inj
Dosing & Administration
Adult Dosing
Standard Dose:
Highly variable based on indication. For eclampsia/preeclampsia: 4-6 g IV over 15-20 min, followed by 1-2 g/hour IV infusion. For hypomagnesemia: 1-4 g IV/IM depending on severity. For Torsades de Pointes: 1-2 g IV over 5-20 min.
Dose Range:
1 - 6 mg
Condition-Specific Dosing:
Eclampsia/Preeclampsia (IV):
Loading dose: 4-6 g over 15-20 min. Maintenance: 1-2 g/hour continuous infusion.
Hypomagnesemia (IV):
Mild: 1-2 g over 1 hour. Severe: 2-4 g over 1-2 hours, then 1-2 g/hour for 6-12 hours.
Torsades de Pointes (IV):
1-2 g diluted in 50-100 mL D5W or NS, given over 5-20 min. May repeat once if necessary.
Asthma Exacerbation (IV):
2 g IV over 20 minutes (for severe acute asthma).
Pediatric Dosing
Neonatal:
Hypomagnesemia: 25-50 mg/kg/dose IV over 1-2 hours, repeat every 8-12 hours for 2-3 doses if needed. Max 2000 mg/day.
Infant:
Hypomagnesemia: 25-50 mg/kg/dose IV over 1-2 hours, repeat every 8-12 hours for 2-3 doses if needed. Max 2000 mg/day.
Child:
Hypomagnesemia: 25-50 mg/kg/dose IV over 1-2 hours, repeat every 8-12 hours for 2-3 doses if needed. Max 2000 mg/day. Asthma Exacerbation: 25-50 mg/kg IV over 10-20 min (max 2 g).
Adolescent:
Hypomagnesemia: 25-50 mg/kg/dose IV over 1-2 hours, repeat every 8-12 hours for 2-3 doses if needed. Max 2000 mg/day. Asthma Exacerbation: 25-50 mg/kg IV over 10-20 min (max 2 g).
Dose Adjustments
Renal Impairment:
Mild:
Reduce maintenance dose by 25-50% or extend dosing interval.
Moderate:
Reduce maintenance dose by 50-75% or extend dosing interval. Monitor serum magnesium closely.
Severe:
Contraindicated or use with extreme caution and significant dose reduction (e.g., 50% or more) with frequent monitoring of serum magnesium, deep tendon reflexes, and respiratory rate. Avoid if possible.
Dialysis:
Not recommended for routine use. If used, administer post-dialysis and monitor serum magnesium levels closely. Magnesium is dialyzable.
Hepatic Impairment:
Mild:
No specific adjustment needed.
Moderate:
No specific adjustment needed.
Severe:
No specific adjustment needed.
Pharmacology
Mechanism of Action
Magnesium is an essential cofactor for many enzyme systems, including those involved in ATP production, nucleic acid synthesis, and muscle contraction. As an anticonvulsant, it depresses the central nervous system by blocking neuromuscular transmission and decreasing the amount of acetylcholine released at the motor end plate. It also acts as a peripheral vasodilator and smooth muscle relaxant, which contributes to its use in preeclampsia/eclampsia and asthma. In Torsades de Pointes, it stabilizes cardiac cell membranes and reduces abnormal electrical activity.
Pharmacokinetics
Absorption:
Bioavailability:
100% (IV/IM)
Tmax:
Immediate (IV), 1 hour (IM)
FoodEffect:
Not applicable (parenteral administration)
Distribution:
Vd:
Not readily quantifiable, distributes throughout body fluids and bone. Approximately 1% of total body magnesium is in extracellular fluid.
ProteinBinding:
Approximately 30% (to albumin)
CnssPenetration:
Limited (does not readily cross intact blood-brain barrier, but can enter CNS with high doses or impaired barrier)
Elimination:
HalfLife:
Approximately 4 hours (normal renal function)
Clearance:
Primarily renal
ExcretionRoute:
Renal (glomerular filtration)
Unchanged:
Nearly 100%
Pharmacodynamics
OnsetOfAction:
Immediate (IV), 1 hour (IM)
PeakEffect:
Immediate (IV), 1 hour (IM)
DurationOfAction:
Approximately 30 minutes (IV), 3-4 hours (IM)
Safety & Warnings
BLACK BOX WARNING
Continuous administration of magnesium sulfate to pregnant women for more than 5-7 days can result in hypocalcemia and bone abnormalities in the developing fetus. These bone abnormalities include osteopenia and fractures. Magnesium sulfate should be used with caution when prolonged administration is required and only when the benefits outweigh the risks.
Side Effects
Urgent Side Effects: Seek Medical Help Immediately
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical attention right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high magnesium levels, including:
+ Confusion
+ Feeling sluggish
+ Slow movements
+ Shortness of breath
+ Upset stomach
+ Severe dizziness or passing out
Signs of low calcium levels, such as:
+ Muscle cramps or spasms
+ Numbness and tingling
+ Seizures
Other severe side effects, including:
+ Slow heartbeat
+ Flushing
+ Inability to move
+ Changes in eyesight
+ Feeling cold
+ Excessive sweating
If you experience any of the following symptoms, call your doctor right away, as they could be signs of a life-threatening muscle problem:
New or worsening muscle weakness
Trouble chewing or swallowing
Trouble breathing
Droopy eyelids
* Changes in eyesight, such as blurred vision or double vision
Other Possible Side Effects
Like all medications, this drug can cause side effects. However, many people do not experience any side effects or only have mild ones. If you have any side effects that bother you or do not go away, contact your doctor or seek medical attention.
Not all possible side effects are listed here. If you have questions about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Although rare, this medication can cause severe and potentially life-threatening side effects. If you experience any of the following symptoms, contact your doctor or seek medical attention right away:
Signs of an allergic reaction, such as:
+ Rash
+ Hives
+ Itching
+ Red, swollen, blistered, or peeling skin with or without fever
+ Wheezing
+ Tightness in the chest or throat
+ Trouble breathing, swallowing, or talking
+ Unusual hoarseness
+ Swelling of the mouth, face, lips, tongue, or throat
Signs of high magnesium levels, including:
+ Confusion
+ Feeling sluggish
+ Slow movements
+ Shortness of breath
+ Upset stomach
+ Severe dizziness or passing out
Signs of low calcium levels, such as:
+ Muscle cramps or spasms
+ Numbness and tingling
+ Seizures
Other severe side effects, including:
+ Slow heartbeat
+ Flushing
+ Inability to move
+ Changes in eyesight
+ Feeling cold
+ Excessive sweating
If you experience any of the following symptoms, call your doctor right away, as they could be signs of a life-threatening muscle problem:
New or worsening muscle weakness
Trouble chewing or swallowing
Trouble breathing
Droopy eyelids
* Changes in eyesight, such as blurred vision or double vision
Other Possible Side Effects
Like all medications, this drug can cause side effects. However, many people do not experience any side effects or only have mild ones. If you have any side effects that bother you or do not go away, contact your doctor or seek medical attention.
Not all possible side effects are listed here. If you have questions about side effects, contact your doctor. You can also report side effects to the FDA at 1-800-332-1088 or online at https://www.fda.gov/medwatch.
Seek Immediate Medical Attention If You Experience:
- Severe drowsiness or lethargy
- Difficulty breathing or slow breathing
- Muscle weakness or inability to move limbs
- Absent reflexes (e.g., knee jerk)
- Flushing or feeling warm
- Low blood pressure (dizziness, lightheadedness)
- Nausea or vomiting
Before Using This Medicine
Before Taking This Medication: Important Information to Share with Your Doctor
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have a heart block or any pre-existing heart problems.
If you are currently taking nifedipine or terbutaline, as these medications may interact with this drug.
Please note that this is not an exhaustive list of potential interactions. To ensure your safety, it is crucial to disclose all of your medications, including:
Prescription and over-the-counter (OTC) drugs
Natural products
Vitamins
Additionally, inform your doctor about any health problems you have. This information will help your doctor determine whether it is safe for you to take this medication in conjunction with your other medications and health conditions.
Remember, do not start, stop, or change the dose of any medication without first consulting your doctor. This will help prevent potential interactions and ensure your safety while taking this medication.
It is essential to inform your doctor about the following:
Any allergies you have, including allergies to this medication, its components, or other substances, such as foods or drugs. Be sure to describe the allergic reaction you experienced, including any symptoms that occurred.
If you have a heart block or any pre-existing heart problems.
If you are currently taking nifedipine or terbutaline, as these medications may interact with this drug.
Please note that this is not an exhaustive list of potential interactions. To ensure your safety, it is crucial to disclose all of your medications, including:
Prescription and over-the-counter (OTC) drugs
Natural products
Vitamins
Additionally, inform your doctor about any health problems you have. This information will help your doctor determine whether it is safe for you to take this medication in conjunction with your other medications and health conditions.
Remember, do not start, stop, or change the dose of any medication without first consulting your doctor. This will help prevent potential interactions and ensure your safety while taking this medication.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. If you are following a low-magnesium diet, consult with your doctor to discuss any potential interactions.
Regular blood tests will be necessary, as directed by your doctor. Be sure to follow their instructions and discuss any concerns or questions you may have with your doctor.
This medication may contain aluminum, which can increase the risk of aluminum toxicity with long-term use. This risk is higher if you have kidney problems or if you are a premature infant. Your doctor will need to monitor you closely to minimize this risk.
Do not take this medication if you have myasthenia gravis, as it can cause severe and potentially life-threatening breathing problems in people with this condition.
If you are pregnant or become pregnant while taking this medication, contact your doctor immediately, as it may harm the unborn baby.
If you are breastfeeding, consult with your doctor to discuss any potential risks to your baby and determine the best course of action.
Regular blood tests will be necessary, as directed by your doctor. Be sure to follow their instructions and discuss any concerns or questions you may have with your doctor.
This medication may contain aluminum, which can increase the risk of aluminum toxicity with long-term use. This risk is higher if you have kidney problems or if you are a premature infant. Your doctor will need to monitor you closely to minimize this risk.
Do not take this medication if you have myasthenia gravis, as it can cause severe and potentially life-threatening breathing problems in people with this condition.
If you are pregnant or become pregnant while taking this medication, contact your doctor immediately, as it may harm the unborn baby.
If you are breastfeeding, consult with your doctor to discuss any potential risks to your baby and determine the best course of action.
Overdose Information
Overdose Symptoms:
- Flushing
- Sweating
- Hypotension
- Bradycardia
- Hypothermia
- Central nervous system depression (drowsiness, confusion, coma)
- Loss of deep tendon reflexes
- Muscle paralysis
- Respiratory depression
- Cardiac arrest
What to Do:
Immediately discontinue magnesium sulfate. Administer intravenous calcium gluconate (10 mL of 10% solution) slowly to counteract magnesium's effects. Provide respiratory support (e.g., mechanical ventilation) if needed. Administer IV fluids to promote renal excretion. Dialysis may be considered in severe cases with renal impairment. Call 1-800-222-1222 (Poison Control).
Drug Interactions
Major Interactions
- Calcium channel blockers (e.g., nifedipine, verapamil, diltiazem): Potentiates hypotensive and neuromuscular blocking effects.
- Neuromuscular blockers (e.g., succinylcholine, rocuronium, vecuronium): Potentiates and prolongs neuromuscular blockade, leading to increased risk of respiratory depression/paralysis.
- CNS depressants (e.g., opioids, benzodiazepines, barbiturates, general anesthetics): Additive CNS depression, increased risk of respiratory depression and sedation.
Moderate Interactions
- Digoxin: High magnesium levels can interfere with digoxin's cardiac effects, potentially leading to bradycardia or heart block.
- Diuretics (loop and thiazide): May increase renal excretion of magnesium, potentially counteracting magnesium supplementation or exacerbating hypomagnesemia.
- Aminoglycosides: May enhance neuromuscular blockade.
Monitoring
Baseline Monitoring
Serum Magnesium
Rationale: To establish baseline levels and guide initial dosing, especially in hypomagnesemia or renal impairment.
Timing: Prior to initiation of therapy.
Renal Function (BUN, Creatinine)
Rationale: Magnesium is renally excreted; impaired renal function increases risk of toxicity.
Timing: Prior to initiation of therapy.
Deep Tendon Reflexes (DTRs)
Rationale: To assess baseline neurological status and monitor for signs of magnesium toxicity (loss of DTRs).
Timing: Prior to initiation of therapy.
Respiratory Rate
Rationale: To assess baseline respiratory status and monitor for respiratory depression.
Timing: Prior to initiation of therapy.
Blood Pressure
Rationale: To assess baseline cardiovascular status and monitor for hypotension.
Timing: Prior to initiation of therapy.
Urine Output
Rationale: To ensure adequate renal excretion of magnesium.
Timing: Prior to initiation of therapy.
Routine Monitoring
Serum Magnesium
Frequency: Every 4-6 hours during continuous infusion, or as clinically indicated.
Target: 4-7 mg/dL (for preeclampsia/eclampsia); 1.5-2.5 mg/dL (normal range)
Action Threshold: >7 mg/dL (loss of DTRs), >10 mg/dL (respiratory depression), >12 mg/dL (cardiac arrest). Adjust dose or hold if levels exceed therapeutic range or signs of toxicity appear.
Deep Tendon Reflexes (DTRs)
Frequency: Hourly during continuous infusion, or every 2-4 hours.
Target: Present (2+)
Action Threshold: Absent DTRs (0) indicate impending toxicity; reduce or hold dose immediately.
Respiratory Rate
Frequency: Hourly during continuous infusion, or every 2-4 hours.
Target: >12 breaths/min
Action Threshold: <12 breaths/min indicates respiratory depression; reduce or hold dose immediately.
Urine Output
Frequency: Hourly during continuous infusion, or every 2-4 hours.
Target: >25-30 mL/hour
Action Threshold: <25 mL/hour indicates impaired renal excretion and increased risk of toxicity; reduce or hold dose immediately.
Blood Pressure
Frequency: Hourly during continuous infusion, or every 2-4 hours.
Target: Within patient's normal range
Action Threshold: Significant hypotension; reduce or hold dose.
ECG (for high doses/toxicity)
Frequency: As clinically indicated, especially with signs of toxicity.
Target: Normal sinus rhythm, no prolonged PR/QT intervals
Action Threshold: Prolonged PR/QT, widened QRS, heart block, asystole.
Symptom Monitoring
- Lethargy
- Drowsiness
- Muscle weakness
- Flushing
- Sweating
- Hypotension
- Bradycardia
- Nausea
- Vomiting
- Slurred speech
- Blurred vision
- Respiratory depression
- Absent deep tendon reflexes
Special Patient Groups
Pregnancy
Category D. Used for prevention and control of seizures in severe preeclampsia and eclampsia. Prolonged administration (more than 5-7 days) can lead to fetal hypocalcemia and bone abnormalities (osteopenia, fractures). Close monitoring of mother and fetus is essential.
Trimester-Specific Risks:
First Trimester:
Generally avoided unless critically indicated due to potential for fetal harm, though primary use is later in pregnancy.
Second Trimester:
Used for preeclampsia/eclampsia management, but prolonged use carries risk of fetal bone abnormalities.
Third Trimester:
Commonly used for preeclampsia/eclampsia management. Risk of fetal bone abnormalities with prolonged use. Neonatal hypotonia, respiratory depression, and hyporeflexia can occur if administered close to delivery.
Lactation
Magnesium is naturally present in breast milk. While magnesium sulfate is excreted into breast milk, the amount is generally considered low and unlikely to cause adverse effects in a healthy, full-term infant. Use with caution in preterm or renally impaired infants. Monitor infant for signs of sedation or diarrhea.
Infant Risk:
Low risk (L3)
Pediatric Use
Dosing is weight-based and varies significantly by indication. Close monitoring of serum magnesium, renal function, and clinical status is crucial due to higher risk of toxicity in neonates and infants. Used for hypomagnesemia, severe asthma, and sometimes for certain arrhythmias.
Geriatric Use
Use with caution due to potential for age-related decline in renal function, which increases the risk of magnesium accumulation and toxicity. Start with lower doses and monitor serum magnesium, renal function, and clinical status closely. More susceptible to CNS and cardiovascular effects.
Clinical Information
Clinical Pearls
- Always have calcium gluconate (10% solution) readily available as an antidote for magnesium toxicity.
- Monitor deep tendon reflexes, respiratory rate, and urine output hourly during continuous IV infusion to detect early signs of toxicity.
- Ensure adequate urine output (>25-30 mL/hour) before and during administration, as renal impairment significantly increases toxicity risk.
- Magnesium sulfate can cause a feeling of warmth or flushing upon administration, which is generally benign.
- In preeclampsia/eclampsia, magnesium sulfate is given to prevent seizures, not to lower blood pressure (though it may have a mild hypotensive effect).
- For IV administration, dilute appropriately and infuse slowly to avoid rapid drops in blood pressure or cardiac arrest.
Alternative Therapies
- For eclampsia/preeclampsia: Other anticonvulsants (e.g., phenytoin, diazepam) are less preferred.
- For hypomagnesemia: Oral magnesium supplements (for mild cases).
- For Torsades de Pointes: Isoproterenol, overdrive pacing.
- For asthma exacerbation: Beta-agonists, corticosteroids, anticholinergics.
Cost & Coverage
Average Cost:
Highly variable, typically low cost for generic IV solution. per 50 mL vial
Generic Available:
Yes
Insurance Coverage:
Generally covered by most insurance plans as a generic injectable.
General Drug Facts
If your symptoms or health problems do not improve or worsen over time, it is essential to contact your doctor for further guidance. To ensure your safety and the safety of others, never share your medication with anyone, and do not take medication prescribed to someone else.
Store all medications in a secure location, out of the reach of children and pets, to prevent accidental ingestion. Properly dispose of any unused or expired medication. Unless instructed to do so by a healthcare professional or pharmacist, do not flush medication down the toilet or pour it down the drain. If you are unsure about the best method for disposing of medication, consult with your pharmacist, as they may be aware of drug take-back programs in your area.
Some medications may come with an additional patient information leaflet, so it is a good idea to check with your pharmacist. If you have any questions or concerns about your medication, do not hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider.
In the event of a suspected overdose, immediately contact your local poison control center or seek medical attention. Be prepared to provide information about the medication taken, the amount, and the time it was taken, as this will be crucial in providing appropriate treatment.
Store all medications in a secure location, out of the reach of children and pets, to prevent accidental ingestion. Properly dispose of any unused or expired medication. Unless instructed to do so by a healthcare professional or pharmacist, do not flush medication down the toilet or pour it down the drain. If you are unsure about the best method for disposing of medication, consult with your pharmacist, as they may be aware of drug take-back programs in your area.
Some medications may come with an additional patient information leaflet, so it is a good idea to check with your pharmacist. If you have any questions or concerns about your medication, do not hesitate to discuss them with your doctor, nurse, pharmacist, or other healthcare provider.
In the event of a suspected overdose, immediately contact your local poison control center or seek medical attention. Be prepared to provide information about the medication taken, the amount, and the time it was taken, as this will be crucial in providing appropriate treatment.