Magnesium 250mg Tablets
It is used to treat or prevent low magnesium levels.It is used to treat heartburn and upset stomach.It may be given to you for other reasons. Talk with the doctor.
Drug Class
Mineral supplement; Laxative, osmotic; Antacid
Pharmacologic Class
Electrolyte; Osmotic agent; Antacid
Pregnancy Category
Category B
FDA Approved
Jan 1970
DEA Schedule
Not Controlled
Overview
What is this medicine?
Magnesium is an important mineral that your body needs for many functions, like muscle and nerve health, blood sugar control, and bone strength. Magnesium oxide can be used as a supplement if you don't get enough magnesium from your diet, or as a laxative to help with constipation, or as an antacid for indigestion.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, it's essential to follow your doctor's instructions carefully. Read all the information provided with your medication and follow the instructions closely. Take your medication with food and a full glass of water.
It's also important to note that this medication may interfere with the absorption of other oral medications. If you take other medications by mouth, you may need to take them at a different time than your current medication. Be sure to discuss this with your doctor to determine the best schedule for your medications.
Storing and Disposing of Your Medication
To maintain the effectiveness and safety of your medication, store it at room temperature in a dry place, away from the bathroom. Keep all medications in a secure location, out of the reach of children and pets. When disposing of unused or expired medications, do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist. Instead, check with your pharmacist for guidance on the best disposal method or explore drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for a missed dose.
To get the most benefit from your medication, it's essential to follow your doctor's instructions carefully. Read all the information provided with your medication and follow the instructions closely. Take your medication with food and a full glass of water.
It's also important to note that this medication may interfere with the absorption of other oral medications. If you take other medications by mouth, you may need to take them at a different time than your current medication. Be sure to discuss this with your doctor to determine the best schedule for your medications.
Storing and Disposing of Your Medication
To maintain the effectiveness and safety of your medication, store it at room temperature in a dry place, away from the bathroom. Keep all medications in a secure location, out of the reach of children and pets. When disposing of unused or expired medications, do not flush them down the toilet or pour them down the drain unless instructed to do so by your pharmacist. Instead, check with your pharmacist for guidance on the best disposal method or explore drug take-back programs in your area.
What to Do If You Miss a Dose
If you miss a dose, take it as soon as you remember. However, if it's close to the time for your next scheduled dose, skip the missed dose and resume your regular dosing schedule. Do not take two doses at the same time or take extra doses to make up for a missed dose.
Lifestyle & Tips
- Take with a full glass of water to help with absorption and reduce stomach upset, especially when used as a laxative.
- If using as a laxative, ensure adequate fluid intake throughout the day to prevent dehydration.
- Separate administration from other medications (especially antibiotics like tetracyclines and fluoroquinolones, and bisphosphonates) by at least 2-4 hours to prevent reduced absorption of those medications.
- Maintain a balanced diet rich in magnesium (e.g., leafy greens, nuts, seeds, whole grains).
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:
For dietary supplement: 200-400 mg elemental magnesium daily. For laxative: 2-4 tablets (500-1000 mg) at bedtime. For antacid: 250-500 mg as needed.
Dose Range:
200 - 1000 mg
Condition-Specific Dosing:
dietary_supplement:
200-400 mg elemental magnesium daily (often 250-500 mg magnesium oxide)
constipation:
500-1000 mg magnesium oxide at bedtime, or as directed by physician
indigestion:
250-500 mg magnesium oxide as needed, up to 4 times daily
Pediatric Dosing
Neonatal:
Not established for routine use; consult pediatrician for specific indications.
Infant:
Not established for routine use; consult pediatrician for specific indications.
Child:
For constipation (ages 6-11): 250-500 mg magnesium oxide once daily or as directed by physician. For ages 12+: Adult dosing.
Adolescent:
For constipation: 500-1000 mg magnesium oxide at bedtime, or as directed by physician.
Dose Adjustments
Renal Impairment:
Mild:
Use with caution; monitor serum magnesium.
Moderate:
Reduced dose or avoid; significant risk of hypermagnesemia. Monitor serum magnesium closely.
Severe:
Contraindicated due to high risk of hypermagnesemia.
Dialysis:
Contraindicated due to high risk of hypermagnesemia.
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 mineral involved in over 300 enzymatic reactions, including protein synthesis, muscle and nerve function, blood glucose control, and blood pressure regulation. As a laxative, magnesium oxide acts as an osmotic agent, drawing water into the intestinal lumen, which softens stool and promotes bowel motility. As an antacid, it neutralizes stomach acid.
Pharmacokinetics
Absorption:
Bioavailability:
Variable, typically 25-60% for dietary magnesium; magnesium oxide has lower bioavailability compared to other salts (e.g., citrate).
Tmax:
Not well-defined for supplement; for laxative effect, onset is typically 0.5-6 hours.
FoodEffect:
Food may slightly decrease absorption but can reduce gastrointestinal upset.
Distribution:
Vd:
Approximately 4-7 L/kg (total body magnesium); primarily stored in bone (50-60%) and soft tissues (20-25%).
ProteinBinding:
Approximately 25-30% bound to plasma proteins.
CnssPenetration:
Limited under normal physiological conditions; increased levels can lead to CNS depression.
Elimination:
HalfLife:
Not a typical drug half-life; plasma magnesium levels are tightly regulated by renal excretion. Renal half-life is approximately 2-4 hours.
Clearance:
Primarily renal clearance.
ExcretionRoute:
Unabsorbed magnesium is excreted in feces; absorbed magnesium is primarily excreted renally.
Unchanged:
Most unabsorbed magnesium is excreted unchanged in feces; absorbed magnesium is excreted unchanged in urine.
Pharmacodynamics
OnsetOfAction:
For laxative effect: 0.5-6 hours. For antacid effect: Rapid (minutes). For supplement effect: Gradual, over days to weeks.
PeakEffect:
For laxative effect: 6-12 hours. For antacid effect: Within 30 minutes. For supplement effect: Not acutely measurable.
DurationOfAction:
For laxative effect: Varies, typically until bowel movement occurs. For antacid effect: 1-3 hours. For supplement effect: Sustained with regular intake.
Safety & Warnings
Side Effects
Urgent Side Effects: Seek Medical Help Right Away
If you experience any of the following symptoms, call your doctor immediately or seek emergency medical attention, as they may be signs of a severe and potentially life-threatening reaction:
- 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
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to monitor your response to the medication. If you notice any of the following side effects or any other unusual effects, and they bother you or do not go away, contact your doctor for advice:
- Diarrhea
Reporting Side Effects
This list does not include all possible side effects. If you have concerns about side effects, discuss them with your doctor. For medical advice 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.
If you experience any of the following symptoms, call your doctor immediately or seek emergency medical attention, as they may be signs of a severe and potentially life-threatening reaction:
- 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
Other Possible Side Effects
Like all medications, this drug can cause side effects. While many people may not experience any side effects or only minor ones, it's essential to monitor your response to the medication. If you notice any of the following side effects or any other unusual effects, and they bother you or do not go away, contact your doctor for advice:
- Diarrhea
Reporting Side Effects
This list does not include all possible side effects. If you have concerns about side effects, discuss them with your doctor. For medical advice 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 diarrhea or watery stools (if using as a laxative)
- Unusual muscle weakness or tiredness
- Dizziness or lightheadedness
- Slow or irregular heartbeat
- Difficulty breathing
- Confusion or lethargy
- Absent or diminished reflexes
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.
All medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. This is crucial to ensure safe use and avoid potential interactions.
* Any existing health problems, as this medication may interact with other medical conditions or drugs.
To guarantee your safety, do not start, stop, or modify the dosage of any medication without first consulting your doctor. It is vital to verify that it is safe to take this medication in conjunction with your other medications and health conditions. Your doctor and pharmacist will work together to ensure that all your medications, including this one, are safe and appropriate for you to take.
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.
All medications you are currently taking, including prescription and over-the-counter (OTC) drugs, natural products, and vitamins. This is crucial to ensure safe use and avoid potential interactions.
* Any existing health problems, as this medication may interact with other medical conditions or drugs.
To guarantee your safety, do not start, stop, or modify the dosage of any medication without first consulting your doctor. It is vital to verify that it is safe to take this medication in conjunction with your other medications and health conditions. Your doctor and pharmacist will work together to ensure that all your medications, including this one, are safe and appropriate for you to take.
Precautions & Cautions
It is essential to inform all of your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Adhere to your doctor's prescribed treatment duration and do not exceed the recommended duration of use. If you are pregnant, planning to become pregnant, or are currently breast-feeding, notify your doctor promptly. You and your doctor will need to discuss the potential benefits and risks of this medication to both you and your baby to make an informed decision.
Overdose Information
Overdose Symptoms:
- Nausea
- Vomiting
- Diarrhea
- Hypotension (low blood pressure)
- Bradycardia (slow heart rate)
- Muscle weakness
- Lethargy
- Drowsiness
- Confusion
- Respiratory depression (slow, shallow breathing)
- Absent deep tendon reflexes
- Coma
- Cardiac arrest
What to Do:
If you suspect an overdose, seek immediate medical attention or call Poison Control at 1-800-222-1222. Management may include IV fluids, calcium gluconate (to antagonize magnesium effects), and in severe cases, dialysis.
Drug Interactions
Contraindicated Interactions
- Severe renal impairment (for high doses)
Major Interactions
- Tetracyclines (e.g., doxycycline, minocycline): Magnesium can chelate and reduce absorption. Separate administration by 2-4 hours.
- Fluoroquinolones (e.g., ciprofloxacin, levofloxacin): Magnesium can chelate and reduce absorption. Separate administration by 2-4 hours.
- Bisphosphonates (e.g., alendronate, risedronate): Magnesium can reduce absorption. Separate administration by at least 30 minutes (preferably longer).
- Calcium Channel Blockers (e.g., amlodipine, diltiazem): Additive hypotensive and bradycardic effects, especially with IV magnesium or high oral doses.
- Neuromuscular Blockers (e.g., rocuronium, succinylcholine): Magnesium can potentiate neuromuscular blockade, leading to prolonged paralysis and respiratory depression.
Moderate Interactions
- Digoxin: High magnesium levels can interfere with digoxin's cardiac effects, potentially leading to heart block or bradycardia.
- Potassium-sparing diuretics (e.g., spironolactone, amiloride): Increased risk of hyperkalemia if hypermagnesemia is also present.
- Levothyroxine: Magnesium can impair absorption. Separate administration by at least 4 hours.
- Mycophenolate mofetil: Reduced absorption of mycophenolate.
Minor Interactions
- Iron supplements: May slightly reduce iron absorption; separate administration by 2 hours.
Monitoring
Baseline Monitoring
Serum Magnesium
Rationale: To establish baseline levels, especially if deficiency is suspected or if patient has renal impairment or other risk factors for hypermagnesemia.
Timing: Prior to initiation of high-dose therapy or in at-risk patients.
Renal Function (BUN, Creatinine, eGFR)
Rationale: Magnesium is renally excreted; impaired renal function increases risk of accumulation and toxicity.
Timing: Prior to initiation, especially for high-dose or long-term therapy.
Routine Monitoring
Serum Magnesium
Frequency: Periodically (e.g., monthly to quarterly) for long-term high-dose therapy or in patients with renal impairment; as clinically indicated for acute use.
Target: 1.7-2.2 mg/dL (0.7-0.9 mmol/L)
Action Threshold: Levels >2.5 mg/dL (1.03 mmol/L) warrant dose reduction or discontinuation; levels >4.8 mg/dL (2.0 mmol/L) are considered toxic and require immediate intervention.
Bowel Function
Frequency: Daily for laxative use.
Target: Regular, soft bowel movements.
Action Threshold: Excessive diarrhea or lack of effect may require dose adjustment.
Blood Pressure, Heart Rate, Respiratory Rate
Frequency: As clinically indicated, especially with higher doses or in patients at risk for hypermagnesemia.
Target: Normal physiological ranges.
Action Threshold: Significant drops in BP, bradycardia, or respiratory depression may indicate hypermagnesemia.
Symptom Monitoring
- Diarrhea
- Abdominal cramping
- Nausea
- Vomiting
- Muscle weakness
- Lethargy
- Drowsiness
- Dizziness
- Hypotension
- Bradycardia
- Respiratory depression
- Absent deep tendon reflexes
Special Patient Groups
Pregnancy
Generally considered safe for use as a dietary supplement during pregnancy at recommended doses. For laxative use, consult a healthcare provider. High doses should be avoided due to potential for hypermagnesemia in the mother and fetus.
Trimester-Specific Risks:
First Trimester:
Generally considered safe for supplementation.
Second Trimester:
Generally considered safe for supplementation.
Third Trimester:
Generally considered safe for supplementation; caution with high doses as it may affect fetal heart rate or cause neonatal hypotonia if given close to delivery.
Lactation
Magnesium is naturally present in breast milk. Oral magnesium oxide is generally considered safe for use during lactation at recommended doses, as significant amounts are not expected to pass into breast milk to harm the infant.
Infant Risk:
Low risk to infant.
Pediatric Use
Use with caution and under medical supervision, especially in infants and young children. Dosing must be carefully adjusted by age and weight. Risk of hypermagnesemia is higher in children, particularly those with renal impairment. Not recommended for long-term use as a laxative without medical advice.
Geriatric Use
Increased risk of hypermagnesemia due to age-related decline in renal function. Start with lower doses and monitor for signs of toxicity (e.g., muscle weakness, lethargy, hypotension). Assess renal function before initiating therapy.
Clinical Information
Clinical Pearls
- Magnesium oxide has lower bioavailability compared to other magnesium salts (e.g., citrate, glycinate) when used as a supplement, but its higher elemental magnesium content per dose makes it a common choice.
- When used as a laxative, magnesium oxide typically produces a bowel movement within 0.5 to 6 hours. Advise patients to take it at bedtime for a morning effect.
- Always advise patients to separate magnesium oxide from interacting medications (especially certain antibiotics and bisphosphonates) by at least 2-4 hours.
- Monitor for signs of hypermagnesemia, particularly in patients with impaired renal function, as symptoms can be subtle initially.
- Patients should be advised to increase fluid intake when using magnesium oxide as a laxative to prevent dehydration and enhance its osmotic effect.
Alternative Therapies
- For constipation: Fiber supplements (e.g., psyllium), stool softeners (e.g., docusate), stimulant laxatives (e.g., senna, bisacodyl), polyethylene glycol (PEG).
- For antacid: Calcium carbonate, aluminum hydroxide, sodium bicarbonate, H2 blockers (e.g., famotidine), proton pump inhibitors (e.g., omeprazole).
- For magnesium deficiency: Dietary changes, other magnesium salts with better absorption.
Cost & Coverage
Average Cost:
$5 - $20 per 100 tablets (250-500mg)
Generic Available:
Yes
Insurance Coverage:
Generally not covered by insurance as it is an over-the-counter (OTC) supplement/medication.
General Drug Facts
If your symptoms or health issues persist or worsen, it is essential to contact your doctor promptly. To ensure safe and effective treatment, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so it is a good idea to consult with your pharmacist. If you have any questions or concerns about this medication, do not hesitate to 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. When reporting the incident, be prepared to provide details about the medication taken, the amount, and the time it occurred.