Magnesium hydroxide

Generic Name: magnesium hydroxide (mag NEE see um hye DROCK side)Brand Names: Concentrated Phillips Milk of Magnesia, Ex-Lax Milk of Magnesia, Milk of Magnesia, Phillips Milk of Magnesia

What is magnesium hydroxide?

Magnesium is a naturally occurring mineral. Magnesium is important for many systems in the body especially the muscles and nerves. Magnesium hydroxide also reduces stomach acid, and increases water in the intestines which may induce defecation.

Magnesium hydroxide is used as a laxative to relieve occasional constipation (irregularity) and as an antacid to relieve indigestion, sour stomach, and heartburn.

Magnesium hydroxide may also be used for purposes other than those listed in this medication guide.

What is the most important information I should know about magnesium hydroxide?

Before taking magnesium hydroxide, tell your doctor if you have any other medical conditions, allergies, or if you take other medicines or other herbal/health supplements. Magnesium hydroxide may not be recommended in some situations.

Do not use magnesium hydroxide as a laxative if you have stomach (abdominal) pain, nausea, or vomiting, unless directed by a doctor. If you notice a sudden change in bowel habits that persists over a period of 2 weeks, consult your healthcare provider before using a laxative. Magnesium hydroxide should not be used for longer than one week, unless otherwise directed by your healthcare provider. Rectal bleeding or failure to have a bowel movement after use of a laxative may indicate a more serious condition; stop using magnesium hydroxide and contact your healthcare provider.

What should I discuss with my healthcare provider before taking magnesium hydroxide?

Do not take magnesium hydroxide without first talking to your doctor if you have kidney disease. Do not use magnesium hydroxide as a laxative if you have stomach (abdominal) pain, nausea, or vomiting, unless directed by a doctor. If you notice a sudden change in bowel habits that persists over a period of 2 weeks, consult your healthcare provider before using a laxative. Magnesium hydroxide should not be used for longer than one week, unless otherwise directed by your healthcare provider. Rectal bleeding or failure to have a bowel movement after use of a laxative may indicate a more serious condition; stop using magnesium hydroxide and contact your healthcare provider.

Before taking magnesium hydroxide, tell your doctor if you have any other medical conditions, allergies, or if you take other medicines or other herbal/health supplements. Magnesium hydroxide may not be recommended in some situations.

It is not known whether magnesium hydroxide will be harmful to an unborn baby. Do not take magnesium hydroxide without first talking to your doctor if you are pregnant or planning a pregnancy. It is not known whether magnesium hydroxide will be harmful to an nursing baby. Do not take magnesium hydroxide without first talking to your doctor if you are breast-feeding a baby.

How should I take magnesium hydroxide?

Take magnesium hydroxide exactly as directed by your doctor or as directed on the package. If you do not understand these directions, ask your pharmacist, nurse, or doctor to explain them to you.

Take the tablets and capsules with a full glass of water.

Chew the chewable tablets thoroughly before swallowing them.

Shake the suspension well before measuring a dose. To ensure that you get the correct dose, measure the liquid form of magnesium with a dose-measuring spoon or cup, not with a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist where you can get one. Do not use magnesium hydroxide as a laxative if you have stomach (abdominal) pain, nausea, or vomiting, unless directed by a doctor. If you notice a sudden change in bowel habits that persists over a period of 2 weeks, consult your healthcare provider before using a laxative. Magnesium hydroxide should not be used for longer than one week, unless otherwise directed by your healthcare provider. Rectal bleeding or failure to have a bowel movement after use of a laxative may indicate a more serious condition; stop using magnesium hydroxide and contact your healthcare provider. Do not take more magnesium hydroxide than is directed. Store magnesium hydroxide at room temperature away from moisture and heat.

See also: Magnesium hydroxide dosage in more detail

What happens if I miss a dose?

Take the missed dose as soon as you remember. However, if it is almost time for the next dose, skip the dose you missed and take only the next regularly scheduled dose. Do not take a double dose of this medication.

What happens if I overdose?

Seek emergency medical attention if an overdose is suspected.

Symptoms of an magnesium hydroxide overdose include nausea, vomiting, flushing, low blood pressure, a slow heartbeat, drowsiness, coma, and death.

What should I avoid while taking magnesium hydroxide?

There are no restrictions on food, beverages, or activity while taking magnesium hydroxide unless otherwise directed by your doctor.

Magnesium hydroxide side effects

Stop taking magnesium hydroxide and seek emergency medical attention if you experience an allergic reaction (difficulty breathing; closing of your throat; swelling of your lips, tongue, or face; or hives).

Other, less serious side effects may be more likely to occur. Continue to take magnesium hydroxide and talk to your doctor if you experience diarrhea or an upset stomach.

Side effects other than those listed here may also occur. Talk to your doctor about any side effect that seems unusual or that is especially bothersome. You may report side effects to FDA at 1-800-FDA-1088.

Magnesium hydroxide Dosing Information

Usual Adult Dose for Constipation:

Oral liquid:30 to 60 mL orally once a day or in divided doses.Chewable tablet:8 tablets orally once a day or in divided doses.

Usual Adult Dose for Dyspepsia:

Oral liquid:Initial dose: 5 to 15 mL orally 1 to 4 times a day as needed.Alternatively, 1 to 3 oral tablets 1 to 4 times a day as needed.Chewable tablet:2 to 4 tablets orally every 4 hours as needed up to 4 times in a 24 hour period.

Usual Pediatric Dose for Constipation:

Oral liquid:1 year or less: 0.5 mL/kg per dose.2 to 5 years: 5 to 15 mL orally once a day or in divided doses.6 to 12 years: 15 to 30 mL orally once a day or in divided doses.13 to 18 years: 30 to 60 mL orally once a day or in divided doses.Chewable tablet:3 to 5 years: 2 tablets orally once a day or in divided doses.6 to 11 years: 4 tablets orally once a day or in divided doses.12 to 18 years: 8 tablets orally once a day or in divided doses.

Usual Pediatric Dose for Dyspepsia:

Chewable tablet:12 to 18 years: 2 to 4 tablets orally every 4 hours up to 4 times in a 24 hour period.

What other drugs will affect magnesium hydroxide?

Before taking magnesium hydroxide, talk to your doctor if you are taking

  • a tetracycline antibiotic such as tetracycline (Sumycin, Achromycin V, and others), demeclocycline (Declomycin), doxycycline (Vibramycin, Monodox, Doxy, and others), minocycline (Minocin, Dynacin, and others), or oxytetracycline (Terramycin, and others);

  • a fluoroquinolone antibiotic such as ciprofloxacin (Cipro), ofloxacin (Floxin), enoxacin (Penetrex), norfloxacin (Noroxin), sparfloxacin (Zagam), levofloxacin (Levaquin), lomefloxacin (Maxaquin), grepafloxacin (Raxar), and others;

  • penicillamine (Cuprimine);

  • digoxin (Lanoxin, Lanoxicaps); or

  • nitrofurantoin (Macrodantin, Furadantin, others).

You not be able to take magnesium hydroxide, or you may require a dosage adjustment or special monitoring during treatment if you are taking any of the medicines listed above.

Drugs other than those listed here can also interact with magnesium hydroxide. Talk to your doctor and pharmacist before taking any over-the-counter or prescription medicines, including vitamins, minerals, and herbal products.

Where can I get more information?

  • Your pharmacist has additional information about magnesium hydroxide written for health professionals that you may read.
  • Consultation with a licensed health care professional is advisable before using any herbal/health supplement. Remember, keep this and all other prescription drug products, over-the-counter drug products, and herbal/health supplements out of the reach of children.
  • Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.
Copyright 1996-2006 Cerner Multum, Inc. Version: 4.02. Revision Date: 4/12/2009 4:38:52 PM.
  • Magnesium Hydroxide MedFacts Consumer Leaflet (Wolters Kluwer)
  • Phillips Milk of Magnesia Advanced Consumer (Micromedex) - Includes Dosage Information
  • Phillips Milk of Magnesia Suspension MedFacts Consumer Leaflet (Wolters Kluwer)