Magnesium Sulfate 80mg/ml Inj
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; Electrolyte
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 certain medical conditions. It can help prevent seizures in pregnant women with severe high blood pressure (preeclampsia/eclampsia), treat low magnesium levels in the body, or help with certain heart rhythm problems or severe asthma attacks. 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 dosage instructions carefully. This medication is administered either as an injection into a muscle or as an infusion into a vein, 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 for guidance on proper storage.
Missing a Dose
If you miss a dose, contact your doctor to determine the best course of action.
To use this medication correctly, follow your doctor's instructions and read all the information provided. It's essential to follow the dosage instructions carefully. This medication is administered either as an injection into a muscle or as an infusion into a vein, 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 for guidance on proper storage.
Missing a Dose
If you miss a dose, contact your doctor to determine the best course of action.
Lifestyle & Tips
- Report any unusual symptoms immediately, especially muscle weakness, difficulty breathing, or feeling very tired.
- Ensure adequate hydration as instructed by your healthcare provider.
- Avoid alcohol and other sedatives while receiving this medication, 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:
Varies significantly by indication. For eclampsia/preeclampsia: Loading dose 4-6 g IV over 15-30 min, followed by maintenance 1-2 g/hour IV infusion. For hypomagnesemia (severe): 8-12 g IV over 5-24 hours. For Torsades de Pointes: 1-2 g IV over 5-20 min.
Dose Range:
1 - 12 mg
Condition-Specific Dosing:
Eclampsia/Preeclampsia:
Loading: 4-6 g IV over 15-30 min; Maintenance: 1-2 g/hour IV infusion. Adjust for renal function.
Hypomagnesemia (severe):
8-12 g IV over 5-24 hours, or 1-2 g IM/IV every 6 hours for 3-4 doses.
Torsades de Pointes:
1-2 g IV over 5-20 min, may repeat once.
Acute severe asthma:
2 g IV over 20 min (adjunctive therapy).
Pediatric Dosing
Neonatal:
Hypomagnesemia: 25-50 mg/kg/dose IV over 1-2 hours, repeat every 8-12 hours for 2-3 doses. Neonatal seizures: 25-50 mg/kg/dose IV over 15-20 min.
Infant:
Hypomagnesemia: 25-50 mg/kg/dose IV over 1-2 hours, repeat every 8-12 hours for 2-3 doses. Acute severe asthma: 25-50 mg/kg IV over 10-20 min (max 2 g).
Child:
Hypomagnesemia: 25-50 mg/kg/dose IV over 1-2 hours, repeat every 8-12 hours for 2-3 doses. Acute severe asthma: 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. Acute severe asthma: 25-50 mg/kg IV over 10-20 min (max 2 g).
Dose Adjustments
Renal Impairment:
Mild:
Monitor closely; consider lower end of dosing range.
Moderate:
Reduce dose by 25-50% or extend dosing interval. Monitor serum magnesium levels closely. For preeclampsia/eclampsia, maintenance infusion may be reduced to 1 g/hour or discontinued if creatinine clearance < 25-30 mL/min.
Severe:
Contraindicated or use with extreme caution and significant dose reduction (e.g., 50-75% reduction) with frequent monitoring of serum magnesium, deep tendon reflexes, and respiratory rate. For preeclampsia/eclampsia, generally contraindicated if anuria or severe renal impairment.
Dialysis:
Magnesium is dialyzable. Avoid use or use with extreme caution and close monitoring. Dosing should be individualized based on pre-dialysis magnesium levels and clinical status.
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 numerous enzymatic reactions, including those involved in phosphate transfer, ATP metabolism, and protein synthesis. As an anticonvulsant, it depresses the central nervous system and blocks peripheral neuromuscular transmission by decreasing the amount of acetylcholine released at the myoneural junction. It also has a direct depressant effect on the smooth muscle of the uterus, acting as a tocolytic. In the cardiovascular system, it can cause vasodilation and has antiarrhythmic properties by slowing the rate of SA node impulse formation and prolonging conduction time through the AV node. In asthma, it may relax bronchial smooth muscle by inhibiting calcium influx.
Pharmacokinetics
Absorption:
Bioavailability:
100% (IV/IM)
Tmax:
Immediate (IV); 1 hour (IM)
FoodEffect:
Not applicable for injection
Distribution:
Vd:
Not readily available, but widely distributed in 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 the blood-brain barrier, but higher doses can cause CNS depression)
Elimination:
HalfLife:
Approximately 4 hours (normal renal function); significantly prolonged in renal impairment.
Clearance:
Primarily renal clearance.
ExcretionRoute:
Renal (urine)
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
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
Although rare, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
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 immediately, as they could be signs of a life-threatening muscle problem:
New or worsening muscle weakness
Difficulty 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 may cause side effects. Many people do not experience any side effects or only have minor ones. If you have any side effects that bother you or do not go away, contact your doctor or seek medical help.
Not all possible side effects are listed here. If you have questions or concerns about side effects, talk to 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, some people may experience severe and potentially life-threatening side effects when taking this medication. If you notice any of the following symptoms, contact your doctor or seek immediate medical attention:
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 immediately, as they could be signs of a life-threatening muscle problem:
New or worsening muscle weakness
Difficulty 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 may cause side effects. Many people do not experience any side effects or only have minor ones. If you have any side effects that bother you or do not go away, contact your doctor or seek medical help.
Not all possible side effects are listed here. If you have questions or concerns about side effects, talk to 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 confusion
- Difficulty breathing or very slow breathing
- Muscle weakness or inability to move limbs
- Absent or very weak reflexes
- Very low blood pressure (dizziness, lightheadedness)
- Slow heart rate
- Decreased urine output
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 drugs, natural products, and vitamins, as well as any health problems you may have. Your doctor and pharmacist need this information to assess the safety of taking this medication in conjunction with your other treatments. Never start, stop, or adjust the dosage of any medication without first consulting 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 drugs, natural products, and vitamins, as well as any health problems you may have. Your doctor and pharmacist need this information to assess the safety of taking this medication in conjunction with your other treatments. Never start, stop, or adjust the dosage of any medication without first consulting your doctor.
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, to monitor your condition. Be sure to follow your doctor's instructions for scheduling these tests and discuss any concerns or questions you may have.
This medication may contain aluminum, which can increase the risk of aluminum toxicity with long-term use. This risk is particularly higher if you have kidney problems or if you are a premature infant. It is crucial to discuss this potential risk with your doctor.
Do not take this medication if you have myasthenia gravis, as it can cause severe and potentially life-threatening breathing problems in individuals with this condition.
If you are pregnant or become pregnant while taking this medication, immediately contact your doctor, as it may harm the unborn baby. Additionally, 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, to monitor your condition. Be sure to follow your doctor's instructions for scheduling these tests and discuss any concerns or questions you may have.
This medication may contain aluminum, which can increase the risk of aluminum toxicity with long-term use. This risk is particularly higher if you have kidney problems or if you are a premature infant. It is crucial to discuss this potential risk with your doctor.
Do not take this medication if you have myasthenia gravis, as it can cause severe and potentially life-threatening breathing problems in individuals with this condition.
If you are pregnant or become pregnant while taking this medication, immediately contact your doctor, as it may harm the unborn baby. Additionally, 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
- Sedation
- Muscle weakness
- Loss of deep tendon reflexes
- Respiratory depression
- Bradycardia
- Cardiac arrest
What to Do:
Immediate medical attention is required. The antidote is intravenous calcium gluconate. Call 911 or your local emergency number. For poison control, call 1-800-222-1222.
Drug Interactions
Major Interactions
- Neuromuscular blockers (e.g., rocuronium, vecuronium): Potentiates neuromuscular blockade, leading to prolonged respiratory depression/paralysis.
- Calcium channel blockers (e.g., nifedipine, amlodipine): Increased risk of hypotension and bradycardia.
- CNS depressants (e.g., opioids, benzodiazepines, general anesthetics): Additive CNS depression, respiratory depression.
Moderate Interactions
- Digoxin: May increase risk of cardiac conduction abnormalities.
- Diuretics (loop and thiazide): May increase renal excretion of magnesium, potentially leading to hypomagnesemia (though magnesium sulfate is used to treat hypomagnesemia, this interaction is relevant for chronic diuretic use).
- Aminoglycosides: May potentiate ototoxicity and nephrotoxicity.
Monitoring
Baseline Monitoring
Renal function (serum creatinine, BUN)
Rationale: Magnesium is renally excreted; impairment increases risk of toxicity.
Timing: Prior to initiation of therapy.
Baseline vital signs (BP, HR, RR)
Rationale: To establish baseline and monitor for adverse effects (hypotension, respiratory depression).
Timing: Prior to initiation of therapy.
Deep tendon reflexes (DTRs)
Rationale: To assess for magnesium toxicity (loss of DTRs is an early sign).
Timing: Prior to initiation of therapy.
Urine output
Rationale: To ensure adequate renal excretion and prevent accumulation.
Timing: Prior to initiation of therapy.
Routine Monitoring
Serum magnesium levels
Frequency: Every 4-6 hours during continuous infusion, or as clinically indicated.
Target: Therapeutic range for eclampsia: 4-7 mEq/L (4.8-8.4 mg/dL).
Action Threshold: >7 mEq/L (8.4 mg/dL) indicates toxicity; >10 mEq/L (12 mg/dL) indicates severe toxicity (loss of DTRs, respiratory depression).
Deep tendon reflexes (DTRs)
Frequency: Hourly or every 2 hours during continuous infusion.
Target: Present (2+).
Action Threshold: Absent DTRs indicate impending toxicity; reduce or hold dose.
Respiratory rate
Frequency: Hourly or every 2 hours during continuous infusion.
Target: >12 breaths/min.
Action Threshold: <12 breaths/min indicates respiratory depression; reduce or hold dose, consider calcium gluconate.
Urine output
Frequency: Hourly or every 2 hours during continuous infusion.
Target: >25-30 mL/hour (or >100 mL/4 hours).
Action Threshold: <25-30 mL/hour indicates impaired renal excretion; reduce or hold dose.
Blood pressure
Frequency: Hourly or every 2 hours during continuous infusion.
Target: Within target range for condition.
Action Threshold: Significant hypotension; reduce or hold dose.
Symptom Monitoring
- Flushing
- Sweating
- Hypotension
- Sedation
- Muscle weakness
- Loss of deep tendon reflexes
- Respiratory depression
- Bradycardia
- Cardiac arrest
- Nausea
- Vomiting
- Blurred vision
Special Patient Groups
Pregnancy
Category D. Used acutely for prevention and treatment of seizures in severe preeclampsia and eclampsia. Prolonged use (more than 5-7 days) for preterm labor is not recommended due to potential for fetal bone abnormalities (e.g., osteopenia, fractures) and should be avoided.
Trimester-Specific Risks:
First Trimester:
Generally avoided unless critically indicated for maternal life-threatening conditions.
Second Trimester:
Acutely used for preeclampsia/eclampsia. Prolonged use for tocolysis is associated with fetal bone abnormalities.
Third Trimester:
Acutely used for preeclampsia/eclampsia. Prolonged use for tocolysis is associated with fetal bone abnormalities.
Lactation
Considered compatible with breastfeeding when used acutely for preeclampsia/eclampsia. Magnesium is a normal component of breast milk. Monitor infant for signs of diarrhea or sedation, though unlikely with typical therapeutic doses.
Infant Risk:
Low risk. Magnesium is naturally present in breast milk. Levels in milk may increase slightly but are generally not clinically significant for the infant.
Pediatric Use
Used for hypomagnesemia, acute severe asthma, and certain arrhythmias. Dosing is weight-based and requires careful monitoring due to potential for toxicity, especially in neonates and infants with immature renal function.
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.
Clinical Information
Clinical Pearls
- Always have calcium gluconate (10% solution, 10 mL IV over 3 minutes) readily available as an antidote for magnesium toxicity.
- Monitor deep tendon reflexes, respiratory rate, and urine output hourly during continuous infusions to detect early signs of toxicity.
- Ensure adequate renal function before and during therapy, as magnesium is primarily renally excreted.
- Magnesium sulfate can cause a feeling of warmth or flushing upon administration, which is usually transient and not a sign of toxicity.
- For preeclampsia/eclampsia, the goal is to achieve therapeutic magnesium levels (4-7 mEq/L) while avoiding toxicity.
- Do not administer intramuscularly if intravenous access is available, due to pain and potential for tissue damage.
Alternative Therapies
- For eclampsia/preeclampsia: Antihypertensives (e.g., labetalol, hydralazine) for blood pressure control, but magnesium sulfate is the primary agent for seizure prophylaxis/treatment.
- For hypomagnesemia: Oral magnesium supplements (for mild cases).
- For Torsades de Pointes: Electrical cardioversion, isoproterenol, overdrive pacing.
- For acute severe asthma: Beta-agonists, corticosteroids, anticholinergics.
Cost & Coverage
Average Cost:
Varies widely by supplier and volume per 50 mL vial (4g/50mL)
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 evaluation and guidance. To ensure safe use, do not share your medication with others, and never take someone else's medication. Store all medications in a secure location, out of reach of children and pets, to prevent accidental ingestion. Dispose of unused or expired medications properly: do not flush them down the toilet or pour them down the drain unless instructed to do so by a healthcare professional or pharmacist. If you are unsure about the proper disposal method, consult with your pharmacist, who can also inform you about potential drug take-back programs in your area. Additionally, some medications may have a separate patient information leaflet; check with your pharmacist for more information. If you have any questions or concerns about your medication, discuss them with your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek emergency medical attention. Be prepared to provide information about the medication taken, the amount, and the time it occurred to ensure prompt and effective treatment.