Calcium and magnesium are naturally occurring minerals that are necessary for many systems in the body. Calcium is necessary for bone formation and maintenance.

Calcium carbonate and magnesium hydroxide is a combination antacid used to treat indigestion, upset stomach, and heartburn.

Calcium carbonate and magnesium hydroxide may also be used for purposes not listed in this medication guide.

Follow all directions on your medicine label and package. Tell each of your healthcare providers about all your medical conditions, allergies, and all medicines you use.

This medication is usually taken between meals or at bedtime. Follow the instructions on the medicine label. Do not use the medication in larger amounts or more often than recommended.

The chewable tablet must be chewed before you swallow it.

Shake the oral suspension (liquid) well just before you measure a dose. Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

Do not take calcium carbonate and magnesium hydroxide for longer than 14 days in a row without medical advice.

Call your doctor if your symptoms do not improve, or if they get worse after 2 weeks of using calcium carbonate and magnesium hydroxide.

Store at room temperature away from moisture and heat. Do not allow the liquid medicine to freeze.

You should not use calcium carbonate and magnesium hydroxide if you have ever had an allergic reaction to an antacid.

Ask a doctor or pharmacist if it is safe for you to take this medicine if you have kidney disease.

Ask a doctor before using this medicine if you are pregnant or breast-feeding. Your dose needs may be different during pregnancy or while you are nursing.

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

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

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

Avoid taking other medications at the same time you take an antacid. Some antacids can make it harder for your body to absorb certain drugs, making them less effective. Take your other medications at least 2 hours before or 2 hours after you take calcium carbonate and magnesium hydroxide.

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

Stop using calcium carbonate and magnesium hydroxide and call your doctor at once if you have symptoms of high calcium or magnesium levels in your blood:

• nausea, vomiting, constipation;

• increased thirst or urination;

• muscle weakness, bone pain;

• confusion, weakness, feeling tired;

• trouble breathing; or

• slow heart rate, feeling light-headed.

Common side effects of calcium carbonate and magnesium hydroxide may include:

• diarrhea;

• constipation; 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.

Many drugs can interact with calcium carbonate and magnesium hydroxide. Not all possible interactions are listed here. Tell your doctor about all your current medicines and any you start or stop using, especially:

• an antibiotic;

• heart or blood pressure medication;

• HIV or AIDS medications; or

• medication to treat osteoporosis or Paget's disease of bone.

This list is not complete and many other drugs can interact with calcium carbonate and magnesium hydroxide. This includes prescription and over-the-counter medicines, vitamins, and herbal products. Give a list of all your medicines to any healthcare provider who treats you.