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Generic name: magnesium oxidemag-NEE-see-um-OCK-side ]
Brand names: MagGel, Phillips' Cramp-free, Uro-Mag
Drug class: Minerals and electrolytes

Medically reviewed by on Apr 18, 2023. Written by Cerner Multum.

What is Uro-Mag?

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

Uro-Mag is used as a supplement to maintain adequate magnesium in the body.

Uro-Mag is also used as an antacid to treat indigestion, or as a laxative to relieve occasional constipation.

Uro-Mag may also be used for purposes not listed in this medication guide.


Before you take Uro-Mag, 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 this medicine, or you may need a dose adjustment or special precautions.

Before taking this medicine

You should not use Uro-Mag if you are allergic to it.

Ask a doctor or pharmacist if it is safe for you to use Uro-Mag 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 Uro-Mag 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.

Uro-Mag should not be given to a child younger than 6 years old.

How should I take Uro-Mag?

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.

Uro-Mag 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.

What happens if I miss a dose?

Since Uro-Mag 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.

What happens if I overdose?

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.

What should I avoid while taking Uro-Mag?

Uro-Mag 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 this medicine. You may need to wait 4 hours to take your other medicines after taking this medicine. Ask your doctor how to best schedule your medications.

Uro-Mag side effects

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

Uro-Mag may cause serious side effects. Stop using Uro-Mag 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 Uro-Mag as a laxative.

Common side effects of Uro-Mag may include:

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.

What other drugs will affect Uro-Mag?

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

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.

Further information

Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.