Milk Of Magnesia Liquid
It is used to treat constipation.It is used to treat heartburn and upset stomach.
Drug Class
Antacid, Laxative
Pharmacologic Class
Inorganic salt, Osmotic laxative, Gastric acid neutralizer
Pregnancy Category
Category B
FDA Approved
Jan 1970
DEA Schedule
Not Controlled
Overview
What is this medicine?
Milk of Magnesia is a liquid medicine used to relieve occasional constipation and indigestion (heartburn/sour stomach). It works by drawing water into your intestines to help with bowel movements, and by neutralizing stomach acid.
How to Use This Medicine
Taking Your Medication Correctly
To use this medication safely and effectively, follow your doctor's instructions carefully. Read all the information provided with your medication and follow the instructions closely.
When taking this medication, swallow it with 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 this medication. Consult with your doctor to determine the best schedule for your medications.
Before using the liquid form of this medication, shake the bottle well. To ensure accurate dosing, measure the liquid carefully using the measuring device provided with the medication. If a measuring device is not included, ask your pharmacist for one.
Storing and Disposing of Your Medication
Store this medication at room temperature in a dry place, avoiding storage in a bathroom.
Missing a Dose
Since this medication is taken as needed, do not take it more frequently than directed by your doctor. If you have any questions or concerns about taking your medication, consult with your doctor or pharmacist for guidance.
To use this medication safely and effectively, follow your doctor's instructions carefully. Read all the information provided with your medication and follow the instructions closely.
When taking this medication, swallow it with 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 this medication. Consult with your doctor to determine the best schedule for your medications.
Before using the liquid form of this medication, shake the bottle well. To ensure accurate dosing, measure the liquid carefully using the measuring device provided with the medication. If a measuring device is not included, ask your pharmacist for one.
Storing and Disposing of Your Medication
Store this medication at room temperature in a dry place, avoiding storage in a bathroom.
Missing a Dose
Since this medication is taken as needed, do not take it more frequently than directed by your doctor. If you have any questions or concerns about taking your medication, consult with your doctor or pharmacist for guidance.
Lifestyle & Tips
- Drink plenty of fluids (water) when taking this medication, especially when using it as a laxative, to prevent dehydration and aid its effect.
- Maintain a balanced diet rich in fiber to help prevent constipation.
- Engage in regular physical activity to promote healthy bowel function.
- Avoid taking other medications within 2-4 hours of Milk of Magnesia, as it can interfere with their absorption.
Available Forms & Alternatives
Dosing & Administration
Adult Dosing
Standard Dose:
Antacid: 5-15 mL (400-1200 mg) as needed, up to 4 times daily. Laxative: 30-60 mL (2400-4800 mg) once daily or as directed.
Dose Range:
5 - 60 mg
Condition-Specific Dosing:
antacid:
5-15 mL (400-1200 mg) as needed
laxative:
30-60 mL (2400-4800 mg) once daily
Pediatric Dosing
Neonatal:
Not established (use only under medical supervision)
Infant:
Not established (use only under medical supervision, risk of hypermagnesemia)
Child:
1-5 years: Laxative: 5-15 mL; Antacid: 2.5-5 mL. 6-11 years: Laxative: 15-30 mL; Antacid: 5-15 mL.
Adolescent:
12 years and older: Adult dosing
Dose Adjustments
Renal Impairment:
Mild:
Use with caution, monitor for hypermagnesemia.
Moderate:
Reduce dose significantly, monitor serum magnesium levels closely. Avoid prolonged use.
Severe:
Contraindicated due to high risk of hypermagnesemia.
Dialysis:
Contraindicated.
Hepatic Impairment:
Mild:
No specific adjustment needed, but monitor renal function as it is the primary elimination route.
Moderate:
No specific adjustment needed, but monitor renal function as it is the primary elimination route.
Severe:
No specific adjustment needed, but monitor renal function as it is the primary elimination route.
Pharmacology
Mechanism of Action
As an antacid, magnesium hydroxide neutralizes gastric acid by reacting with hydrochloric acid in the stomach to form magnesium chloride and water, increasing gastric pH. As a laxative, it acts as an osmotic agent, drawing water into the intestinal lumen, which increases stool volume and stimulates peristalsis.
Pharmacokinetics
Absorption:
Bioavailability:
Approximately 15-30% of magnesium is absorbed from the gastrointestinal tract.
Tmax:
Not directly applicable for antacid/laxative effect; for absorbed magnesium, variable (hours).
FoodEffect:
Food may delay gastric emptying, potentially prolonging antacid effect.
Distribution:
Vd:
Magnesium distributes widely throughout the body, with about 50-60% in bone, 20-25% in muscle, and the remainder in soft tissues and extracellular fluid.
ProteinBinding:
Approximately 30% of plasma magnesium is protein-bound.
CnssPenetration:
Yes, high serum concentrations can lead to CNS depression.
Elimination:
HalfLife:
Plasma half-life of absorbed magnesium is 2-6 hours in individuals with normal renal function.
Clearance:
Primarily renal clearance for absorbed magnesium.
ExcretionRoute:
Unabsorbed magnesium is excreted in feces. Absorbed magnesium is excreted renally.
Unchanged:
Nearly 100% of the absorbed portion is excreted unchanged in urine.
Pharmacodynamics
OnsetOfAction:
Antacid: Rapid (within minutes). Laxative: 30 minutes to 6 hours.
PeakEffect:
Antacid: Varies with gastric emptying. Laxative: 1-6 hours.
DurationOfAction:
Antacid: 1-3 hours (depending on gastric emptying). Laxative: Varies, typically until bowel evacuation.
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, 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 mild ones, it's essential to discuss any concerns with your doctor. Contact your doctor if you experience:
- Diarrhea
or any other side effects that bother you or do not go away.
Reporting Side Effects
This list is not exhaustive, and you may have questions about other side effects. If so, consult your doctor for advice. 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, 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 mild ones, it's essential to discuss any concerns with your doctor. Contact your doctor if you experience:
- Diarrhea
or any other side effects that bother you or do not go away.
Reporting Side Effects
This list is not exhaustive, and you may have questions about other side effects. If so, consult your doctor for advice. 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 abdominal pain or cramping
- Rectal bleeding
- Failure to have a bowel movement after using as a laxative
- Signs of hypermagnesemia: unusual tiredness, muscle weakness, slow heartbeat, dizziness, confusion, difficulty breathing.
- Symptoms of an allergic reaction: rash, itching, swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.
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 and its symptoms.
Certain health conditions, including:
+ Bowel obstruction or blockage
+ Abdominal pain
+ Upset stomach
+ Rectal bleeding
+ Vomiting
+ Changes in bowel habits that last longer than 2 weeks
Kidney disease or any other kidney problems
This list is not exhaustive, and it is crucial to discuss all your health conditions and medications with your doctor.
To ensure your safety, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Natural products and vitamins you are using
Any health problems you have
Before starting, stopping, or changing the dose of any medication, including this one, consult with your doctor to confirm it is safe for you to do so.
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 and its symptoms.
Certain health conditions, including:
+ Bowel obstruction or blockage
+ Abdominal pain
+ Upset stomach
+ Rectal bleeding
+ Vomiting
+ Changes in bowel habits that last longer than 2 weeks
Kidney disease or any other kidney problems
This list is not exhaustive, and it is crucial to discuss all your health conditions and medications with your doctor.
To ensure your safety, provide your doctor and pharmacist with a comprehensive list of:
All prescription and over-the-counter (OTC) medications you are taking
Natural products and vitamins you are using
Any health problems you have
Before starting, stopping, or changing the dose of any medication, including this one, consult with your doctor to confirm it is safe for you to do so.
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. Do not use this medication for more than 1 week without explicit instruction from your doctor. If you experience rectal bleeding or fail to have a bowel movement after using this drug, promptly consult with your doctor. Additionally, if you are pregnant, planning to become pregnant, or are breast-feeding, notify your doctor to discuss the potential benefits and risks of this medication to both you and your baby.
Overdose Information
Overdose Symptoms:
- Severe diarrhea
- Dehydration
- Profound muscle weakness
- Lethargy
- Drowsiness progressing to coma
- Hypotension (low blood pressure)
- Bradycardia (slow heart rate)
- Respiratory depression
- Loss of deep tendon reflexes
What to Do:
Discontinue use immediately. Seek emergency medical attention. For severe hypermagnesemia, intravenous calcium gluconate may be administered to antagonize magnesium's effects. Dialysis may be necessary in severe cases, especially with renal impairment. Call 1-800-222-1222 (Poison Control Center).
Drug Interactions
Major Interactions
- Tetracyclines (e.g., doxycycline, minocycline): Reduced absorption due to chelation. Separate administration by 2-4 hours.
- Fluoroquinolones (e.g., ciprofloxacin, levofloxacin): Reduced absorption due to chelation. Separate administration by 2-4 hours.
Moderate Interactions
- Bisphosphonates (e.g., alendronate): Reduced absorption. Separate administration by at least 30 minutes (preferably longer).
- Digoxin: Reduced absorption. Separate administration by several hours.
- Iron salts: Reduced absorption. Separate administration by 2-4 hours.
- Thyroid hormones (e.g., levothyroxine): Reduced absorption. Separate administration by 4 hours.
- Mycophenolate: Reduced absorption. Avoid concomitant use.
- Sodium polystyrene sulfonate (Kayexalate): Risk of metabolic alkalosis and intestinal necrosis (rare, but serious).
Minor Interactions
- H2-receptor antagonists (e.g., ranitidine, famotidine): May reduce absorption of H2RAs due to increased gastric pH.
- Proton pump inhibitors (e.g., omeprazole, pantoprazole): May reduce absorption of PPIs due to increased gastric pH.
Monitoring
Baseline Monitoring
Renal function (e.g., serum creatinine, eGFR)
Rationale: Magnesium is primarily renally excreted; impaired renal function increases risk of hypermagnesemia.
Timing: Prior to initiation, especially in elderly or those with known renal issues.
Serum electrolytes (Magnesium, Calcium, Potassium)
Rationale: To establish baseline and identify pre-existing imbalances, particularly if prolonged use or renal impairment is anticipated.
Timing: Prior to initiation for high-risk patients.
Routine Monitoring
Bowel movements and consistency
Frequency: Daily during use for laxative effect.
Target: Soft, formed stools; relief of constipation.
Action Threshold: Persistent diarrhea, abdominal cramping, or lack of effect.
Symptom relief (e.g., heartburn, indigestion)
Frequency: As needed during use for antacid effect.
Target: Reduction or elimination of symptoms.
Action Threshold: Persistent or worsening symptoms.
Serum magnesium levels
Frequency: Periodically (e.g., weekly to monthly) for prolonged use or in patients with renal impairment.
Target: 1.5-2.5 mg/dL (0.6-1.0 mmol/L)
Action Threshold: Levels > 2.5 mg/dL or signs/symptoms of hypermagnesemia.
Symptom Monitoring
- Diarrhea
- Abdominal cramping
- Nausea
- Vomiting
- Muscle weakness
- Drowsiness
- Dizziness
- Confusion
- Slowed heart rate (bradycardia)
- Low blood pressure (hypotension)
- Reduced deep tendon reflexes
- Difficulty breathing (in severe hypermagnesemia)
Special Patient Groups
Pregnancy
Generally considered safe for occasional use during pregnancy for constipation or heartburn, but prolonged or high-dose use should be avoided due to potential for electrolyte imbalance in the mother and fetus. Consult a healthcare provider.
Trimester-Specific Risks:
First Trimester:
Low risk with occasional use.
Second Trimester:
Low risk with occasional use.
Third Trimester:
Low risk with occasional use, but caution with prolonged use near term due to potential for neonatal hypermagnesemia (rare).
Lactation
Considered safe for use during breastfeeding. Magnesium is a normal component of breast milk, and the amount transferred from typical doses is not expected to harm the infant.
Infant Risk:
Low risk.
Pediatric Use
Use with caution, especially in infants and young children, due to increased risk of hypermagnesemia and dehydration. Dosing must be age-appropriate and often requires medical supervision, particularly for infants under 1 year. Not recommended for long-term use in children.
Geriatric Use
Use with caution due to increased likelihood of impaired renal function, which increases the risk of magnesium accumulation and hypermagnesemia. Start with lower doses and monitor for adverse effects and electrolyte imbalances.
Clinical Information
Clinical Pearls
- Shake the bottle well before each use to ensure uniform suspension.
- For laxative effect, take on an empty stomach for faster action. For antacid effect, take after meals or at bedtime.
- Do not use as a laxative for more than 7 days or as an antacid for more than 14 days without consulting a doctor.
- Advise patients to separate administration from other medications by at least 2-4 hours to avoid drug interactions.
- Educate patients on the signs and symptoms of hypermagnesemia, especially those with kidney disease.
- Not suitable for chronic constipation; lifestyle modifications and fiber are preferred first-line treatments.
Alternative Therapies
- For constipation: Polyethylene glycol (PEG), lactulose, docusate sodium, psyllium (fiber supplements), senna, bisacodyl.
- For heartburn/indigestion: Calcium carbonate (Tums), aluminum hydroxide, H2-receptor antagonists (e.g., famotidine), proton pump inhibitors (e.g., omeprazole).
Cost & Coverage
Average Cost:
$5 - $20 per 355 mL (12 fl oz) bottle
Generic Available:
Yes
Insurance Coverage:
Generally not covered by prescription insurance as it is an over-the-counter (OTC) product. May be eligible for FSA/HSA.
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 happened.