Magnesium Oxide 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
Magnesium salt
Pregnancy Category
Category B
FDA Approved
Jan 1970
DEA Schedule
Not Controlled
Overview
What is this medicine?
Magnesium oxide is a mineral supplement that can also be used as a laxative to treat constipation or as an antacid to relieve heartburn and indigestion. It works by helping your body get enough magnesium, drawing water into your bowels to soften stool, or neutralizing stomach acid.
How to Use This Medicine
Taking Your Medication Correctly
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. Take your medication with food and a full glass of water.
It's essential 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. Consult with your doctor to determine the best schedule for your medications.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of the reach of children and pets. 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 your pharmacist. If you have questions about disposing of your medication, consult with your pharmacist, who can also inform you about potential 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 dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
To get the most benefit from your medication, follow your doctor's instructions carefully. Read all the information provided with your prescription and follow the instructions closely. Take your medication with food and a full glass of water.
It's essential 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. Consult with your doctor to determine the best schedule for your medications.
Storing and Disposing of Your Medication
Store your medication at room temperature in a dry place, avoiding the bathroom. Keep all medications in a safe location, out of the reach of children and pets. 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 your pharmacist. If you have questions about disposing of your medication, consult with your pharmacist, who can also inform you about potential 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 dose, skip the missed dose and resume your regular schedule. Do not take two doses at the same time or take extra doses to make up for the missed one.
Lifestyle & Tips
- Take with a full glass of water to help with absorption and prevent constipation.
- If using as a laxative, ensure adequate fluid intake 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.
- Do not exceed recommended doses without consulting a healthcare professional.
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 constipation: 1.2-2.4 g (elemental magnesium) daily in divided doses. For dyspepsia: 400-800 mg (elemental magnesium) as needed.
Dose Range:
200 - 2400 mg
Condition-Specific Dosing:
dietarySupplement:
200-400 mg elemental magnesium daily
constipation:
1.2-2.4 g elemental magnesium daily in divided doses
dyspepsia:
400-800 mg elemental magnesium as needed
Pediatric Dosing
Neonatal:
Not established
Infant:
Not established (use with caution and medical supervision)
Child:
For constipation (off-label): 400-800 mg elemental magnesium daily in divided doses (consult pediatrician). For supplement: Varies by age, typically lower doses than adults.
Adolescent:
Similar to adult dosing for constipation or supplement, but generally lower end of adult range.
Dose Adjustments
Renal Impairment:
Mild:
Use with caution; monitor serum magnesium.
Moderate:
Reduce dose by 50% or avoid; monitor serum magnesium closely.
Severe:
Contraindicated due to risk of hypermagnesemia.
Dialysis:
Contraindicated due to risk of hypermagnesemia; magnesium is not effectively removed by standard hemodialysis.
Hepatic Impairment:
Mild:
No specific adjustment needed.
Moderate:
No specific adjustment needed.
Severe:
No specific adjustment needed.
Pharmacology
Mechanism of Action
As a dietary supplement, 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 an osmotic laxative, magnesium oxide draws water into the intestines, softening stool and promoting bowel movements. As an antacid, it neutralizes stomach acid by reacting with hydrochloric acid to form magnesium chloride and water.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 4-50% (highly variable, depends on dose and individual status)
Tmax:
1-4 hours (for laxative effect, onset is typically 0.5-6 hours)
FoodEffect:
Food may slightly decrease absorption but can reduce gastrointestinal upset.
Distribution:
Vd:
Not available (widely distributed in bone, muscle, and soft tissues)
ProteinBinding:
Approximately 25-30%
CnssPenetration:
Limited (significant CNS penetration only with very high serum levels)
Elimination:
HalfLife:
Not precisely defined for exogenous magnesium; depends on renal function (normal renal function: excess magnesium is rapidly excreted)
Clearance:
Primarily renal clearance
ExcretionRoute:
Renal (urine), Fecal (unabsorbed portion)
Unchanged:
100% (absorbed portion)
Pharmacodynamics
OnsetOfAction:
Antacid: Minutes; Laxative: 0.5-6 hours; Supplement: Weeks to months for full repletion
PeakEffect:
Antacid: 30-60 minutes; Laxative: 2-8 hours
DurationOfAction:
Antacid: 1-3 hours; Laxative: Varies, typically until bowel movement occurs
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, difficulty breathing, swallowing, or talking, unusual hoarseness, or 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 discuss any concerns with your doctor. Contact your doctor if you experience:
- Diarrhea
or if any other side effects bother you or do not go away.
Reporting Side Effects
This list does not include all possible side effects. If you have questions or concerns about side effects, consult 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, difficulty breathing, swallowing, or talking, unusual hoarseness, or 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 discuss any concerns with your doctor. Contact your doctor if you experience:
- Diarrhea
or if any other side effects bother you or do not go away.
Reporting Side Effects
This list does not include all possible side effects. If you have questions or concerns about side effects, consult 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
- Muscle weakness
- Extreme tiredness or drowsiness
- Dizziness or lightheadedness
- Slow heartbeat
- Difficulty breathing
- Confusion
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 symptoms you experienced as a result of the allergy.
Potential interactions with other medications or health conditions. This medication may interact with other prescription or over-the-counter (OTC) medications, natural products, or vitamins, which could affect its safety and efficacy.
A complete list of all your current medications, including prescription and OTC drugs, natural products, and vitamins. This will help your doctor and pharmacist assess potential interactions and ensure safe use.
Any existing health problems, as these may impact the safety and effectiveness of this medication.
To ensure your safety, do not start, stop, or change the dose of any medication without first consulting your doctor. It is crucial to verify that it is safe to take this medication with all your other medications and health conditions.
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 symptoms you experienced as a result of the allergy.
Potential interactions with other medications or health conditions. This medication may interact with other prescription or over-the-counter (OTC) medications, natural products, or vitamins, which could affect its safety and efficacy.
A complete list of all your current medications, including prescription and OTC drugs, natural products, and vitamins. This will help your doctor and pharmacist assess potential interactions and ensure safe use.
Any existing health problems, as these may impact the safety and effectiveness of this medication.
To ensure your safety, do not start, stop, or change the dose of any medication without first consulting your doctor. It is crucial to verify that it is safe to take this medication with all your other medications and health conditions.
Precautions & Cautions
It is essential to inform all your healthcare providers, including doctors, nurses, pharmacists, and dentists, that you are taking this medication. Adhere to your doctor's prescribed duration for taking this drug and avoid exceeding the recommended treatment period. If you are pregnant, planning to become pregnant, or are currently breast-feeding, notify your doctor immediately. 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
- Abdominal pain
- Hypotension
- Bradycardia
- Muscle weakness
- Lethargy
- Drowsiness
- Confusion
- Absent deep tendon reflexes
- Respiratory depression
- Cardiac arrest
What to Do:
Discontinue magnesium oxide. Administer intravenous calcium gluconate to antagonize magnesium's effects. Provide supportive care, including respiratory support if needed. In severe cases with normal renal function, forced diuresis with intravenous fluids may be used. Dialysis may be necessary in patients with renal failure. Call 1-800-222-1222 (Poison Control).
Drug Interactions
Major Interactions
- Tetracyclines (e.g., doxycycline, minocycline): Magnesium can chelate these antibiotics, significantly reducing their absorption. Separate administration by at least 2-4 hours.
- Fluoroquinolones (e.g., ciprofloxacin, levofloxacin): Magnesium can chelate these antibiotics, significantly reducing their absorption. Separate administration by at least 2-6 hours.
- Bisphosphonates (e.g., alendronate, risedronate): Magnesium can interfere with the absorption of bisphosphonates. Separate administration by at least 30 minutes to 2 hours.
Moderate Interactions
- Potassium-sparing diuretics (e.g., amiloride, spironolactone, triamterene): May increase risk of hypermagnesemia, especially in patients with renal impairment.
- Calcium channel blockers (e.g., amlodipine, nifedipine): May have additive hypotensive effects or enhance neuromuscular blockade.
- Neuromuscular blockers (e.g., rocuronium, succinylcholine): Magnesium can enhance the effects of neuromuscular blockers, leading to prolonged paralysis.
- Digoxin: High magnesium levels can interfere with digoxin's cardiac effects and lead to heart block.
- Levothyroxine: Magnesium can impair the absorption of levothyroxine. Separate administration by at least 4 hours.
Minor Interactions
- Other laxatives: Concurrent use may lead to excessive laxative effect (diarrhea, dehydration).
- Antacids (other): Concurrent use may lead to excessive antacid effect or electrolyte imbalance.
Monitoring
Baseline Monitoring
Renal function (BUN, creatinine)
Rationale: Magnesium is renally excreted; impaired renal function increases risk of hypermagnesemia.
Timing: Prior to initiating high-dose or chronic therapy, especially in elderly or those with known renal issues.
Serum magnesium levels
Rationale: To establish baseline, especially if deficiency is suspected or high doses are planned.
Timing: Prior to initiating therapy for hypomagnesemia.
Routine Monitoring
Serum magnesium levels
Frequency: Periodically (e.g., weekly to monthly) for patients on high doses, with renal impairment, or experiencing symptoms of hypermagnesemia.
Target: 1.7-2.2 mg/dL (0.7-0.9 mmol/L)
Action Threshold: If >2.5 mg/dL, consider dose reduction or discontinuation; if >4.0 mg/dL, immediate intervention for hypermagnesemia.
Bowel movements
Frequency: Daily (for laxative use)
Target: Regular, soft, formed stools
Action Threshold: Excessive diarrhea or no bowel movement after 3 days of laxative use.
Blood pressure, heart rate
Frequency: Periodically, especially with high doses or in patients with cardiovascular conditions.
Target: Within normal limits for the patient
Action Threshold: Significant hypotension or bradycardia.
Symptom Monitoring
- Diarrhea
- Abdominal cramping
- Nausea
- Vomiting
- Muscle weakness
- Lethargy
- Drowsiness
- Confusion
- Hypotension
- Bradycardia
- Respiratory depression (severe hypermagnesemia)
- Absent deep tendon reflexes (severe hypermagnesemia)
Special Patient Groups
Pregnancy
Generally considered safe for short-term use as a laxative or antacid during pregnancy, especially in the second and third trimesters. However, high doses or prolonged use should be avoided due to potential for hypermagnesemia in the mother and fetus. Consult a healthcare provider.
Trimester-Specific Risks:
First Trimester:
Low risk with typical doses; generally considered safe for short-term use.
Second Trimester:
Low risk with typical doses; commonly used for constipation or heartburn.
Third Trimester:
Low risk with typical doses; caution with very high doses due to potential for neonatal hypotonia or respiratory depression if maternal hypermagnesemia occurs near delivery.
Lactation
Magnesium is a normal component of breast milk. Oral magnesium oxide is considered compatible with breastfeeding when used at recommended doses. Minimal amounts are excreted into breast milk, and adverse effects on the infant are unlikely.
Infant Risk:
Low risk (L1)
Pediatric Use
Use with caution, especially as a laxative in young children, due to risk of dehydration and electrolyte imbalance. Dosing should be determined by a pediatrician. Not recommended for infants without medical supervision.
Geriatric Use
Increased risk of hypermagnesemia due to age-related decline in renal function. Start with lower doses and monitor renal function and serum magnesium levels closely. More susceptible to adverse effects like diarrhea and dehydration.
Clinical Information
Clinical Pearls
- Magnesium oxide has a lower bioavailability compared to other magnesium salts (e.g., citrate, aspartate, glycinate) when used as a supplement, meaning a larger dose is needed to achieve the same elemental magnesium absorption.
- It is often preferred as a laxative or antacid due to its osmotic and neutralizing properties, respectively.
- Advise patients to take magnesium oxide with food if gastrointestinal upset occurs.
- Emphasize the importance of separating administration from interacting medications to ensure proper absorption of both drugs.
- Patients with kidney disease should avoid magnesium oxide unless specifically advised and monitored by a physician.
Alternative Therapies
- For magnesium deficiency: Magnesium citrate, magnesium glycinate, magnesium aspartate (often better absorbed).
- For constipation: Polyethylene glycol (PEG), docusate sodium, senna, bisacodyl, lactulose, psyllium.
- For dyspepsia/antacid: Calcium carbonate, aluminum hydroxide, sodium bicarbonate, H2 blockers (e.g., famotidine), proton pump inhibitors (e.g., omeprazole).
Cost & Coverage
Average Cost:
$5 - $20 per 100 tablets (250mg)
Generic Available:
Yes
Insurance Coverage:
Generally OTC, not typically covered by insurance unless prescribed.
General Drug Facts
If your symptoms or health issues persist or worsen, it's essential to contact your doctor for further guidance. To ensure your safety, never share your medication with others or take someone else's medication. Some medications may come with an additional patient information leaflet, so be sure to check with your pharmacist for more information. If you have any questions or concerns about your medication, don't hesitate to reach out to your doctor, nurse, pharmacist, or other healthcare provider. In the event of a suspected overdose, immediately call your local poison control center or seek medical attention. When seeking help, be prepared to provide details about the medication taken, the amount, and the time it occurred.