Magnesium is a naturally occurring mineral. Magnesium is important for many systems in the body especially the muscles and nerves.

Magnesium oxide is used as a supplement to maintain adequate magnesium in the body.

Magnesium oxide is also used as an antacid to treat indigestion, or as a laxative to relieve occasional constipation.

Magnesium oxide may also be used for purposes not listed in this medication guide.

Before you take magnesium oxide, tell your doctor about all your medical conditions or allergies, and all the medicines you are using. Also make sure your doctor knows if you are pregnant or breast-feeding. In some cases, you may not be able to take magnesium oxide, or you may need a dose adjustment or special precautions.

Magnesium oxide comes as a tablet and capsule to take by mouth. It usually is taken one to four times daily depending on which brand is used and what condition you have. Follow the directions on the package or on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take magnesium oxide exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.

Take any other medicine and magnesium oxide at least 2 hours apart.

If you are using magnesium oxide as a laxative, take it with a full glass (8 ounces [240 milliliters]) of cold water or fruit juice. Do not take a dose late in the day on an empty stomach.

Do not take magnesium oxide as an antacid for longer than 2 weeks unless your doctor tells you to. Do not take magnesium oxide as a laxative for more than 1 week unless your doctor tells you to.

Use exactly as directed on the label, or as prescribed by your doctor. Do not use in larger or smaller amounts or for longer than recommended.

Take this medicine with a full glass of water.

When using this medicine as a laxative, it may be best to take your dose at bedtime.

Magnesium oxide may be taken with food if it upsets your stomach.

Call your doctor if your symptoms do not improve after 7 days of treatment, or if symptoms get worse.

Store at room temperature away from moisture and heat.

You should not use magnesium oxide if you are allergic to it.

Ask a doctor or pharmacist if it is safe for you to use magnesium oxide if you have other medical conditions, especially:

• kidney disease;

• heart disease;

• nausea, vomiting;

• a blockage in your intestines;

• low levels of calcium in your blood; or

• a sudden change in bowel habits for 2 weeks or longer.

It is not known whether magnesium oxide will harm an unborn baby. Ask a doctor before using this medicine if you are pregnant.

It is not known whether magnesium oxide passes into breast milk or if it could affect a nursing baby. Ask a doctor before using this medicine if you are breast-feeding.

Do not give this medicine to a child without medical advice.

Magnesium oxide should not be given to a child younger than 6 years old.

Since magnesium oxide is sometimes used when needed, you may not be on a dosing schedule. If you are on a schedule, take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include nausea, vomiting, weakness, breathing problems, slow reflexes, weak pulse, extreme drowsiness, and feeling dizzy or light-headed.

Keep this medication in the container it came in, tightly closed, and out of reach of children. Store it at room temperature and away from excess heat and moisture (not in the bathroom).

Unneeded medications should be disposed of in special ways to ensure that pets, children, and other people cannot consume them. However, you should not flush this medication down the toilet. Instead, the best way to dispose of your medication is through a medicine take-back program. Talk to your pharmacist or contact your local garbage/recycling department to learn about take-back programs in your community. See the FDA's Safe Disposal of Medicines website (http://goo.gl/c4Rm4p) for more information if you do not have access to a take-back program.

It is important to keep all medication out of sight and reach of children as many containers (such as weekly pill minders and those for eye drops, creams, patches, and inhalers) are not child-resistant and young children can open them easily. To protect young children from poisoning, always lock safety caps and immediately place the medication in a safe location – one that is up and away and out of their sight and reach. http://www.upandaway.org

Magnesium oxide can make it harder for your body to absorb other medicines you take by mouth. Avoid taking other medicines within 2 hours before or 2 hours after you take magnesium oxide. You may need to wait 4 hours to take your other medicines after taking magnesium oxide. Ask your doctor how to best schedule your medications.

Get emergency medical help if you have signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.

Magnesium oxide may cause serious side effects. Stop using magnesium oxide and call your doctor at once if you have:

• rectal bleeding;

• coughing up blood or vomit that looks like coffee grounds;

• bloody or tarry stools; or

• no bowel movement after using magnesium oxide as a laxative.

Common side effects of magnesium oxide may include:

• diarrhea; or

• upset stomach.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Ask a doctor or pharmacist if it is safe for you to take magnesium oxide if you are also using any of the following drugs:

• an antibiotic;

• a diuretic or "water pill";

• penicillamine;

• a blood thinner--warfarin, Coumadin, Jantoven; or

• medicine to treat osteoporosis or Paget's disease--alendronate, ibandronate, risedronate, Fosamax, Boniva, Actonel, and others.

This list is not complete. Other drugs may interact with magnesium oxide, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible interactions are listed in this medication guide.

If this medicine has been prescribed for you, keep all appointments with your doctor so that your response to magnesium can be checked.

Do not let anyone else take your medicine.

It is important for you to keep a written list of all of the prescription and nonprescription (over-the-counter) medicines you are taking, as well as any products such as vitamins, minerals, or other dietary supplements. You should bring this list with you each time you visit a doctor or if you are admitted to a hospital. It is also important information to carry with you in case of emergencies.