Health Library

Calcium carbonate with magnesium overdose

Rolaids overdose; Antacids overdose

The combination of calcium carbonate and magnesium is commonly found in antacids. These medicines provide heartburn relief.

Calcium carbonate with magnesium overdose occurs when someone takes more than the normal or recommended amount of medicine that contains these ingredients. The overdose may be by accident or on purpose.

This article is for information only. DO NOT use it to treat or manage an actual overdose. If you or someone you are with overdoses, call the local emergency number (such as 911), or the local poison control center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States.

I Would Like to Learn About:

Poisonous Ingredient

Calcium carbonate and magnesium

Where Found

Calcium carbonate with magnesium is found in many (but not all) antacids, including the following brands:

• Maalox
• Mylanta
• Rolaids
• Tums

Other antacids may also contain calcium carbonate and magnesium.

Symptoms

Symptoms of an overdose of calcium carbonate and magnesium include:

• Bone pain (from chronic overuse)
• Constipation
• Decreased reflexes
• Diarrhea
• Dry mouth
• Irregular heartbeat
• Poor balance
• Shallow, rapid breathing
• Skin flushing
• Stupor (lack of alertness)

Home Care

Seek medical help right away. Do not make a person throw up unless poison control or a health care provider tells you to.

Before Calling Emergency

Have this information ready:

• Person's age, weight, and condition
• Name of the product (ingredients and strength, if known)
• Time it was swallowed
• Amount swallowed
• If the medicine was prescribed for the person

Poison Control

The local poison control center can be reached directly by calling the national toll-free Poison Help hotline (1-800-222-1222) from anywhere in the United States. This national hotline number will let you talk to experts in poisoning. They will give you further instructions.

This is a free and confidential service. All local poison control centers in the United States use this national number. You should call if you have any questions about poisoning or poison prevention. It does NOT need to be an emergency. You can call for any reason, 24 hours a day, 7 days a week.

You can also get online poison help now at Poisonhelp.org. Just enter the product, poison, or medicine to get expert help.

What to Expect at the Emergency Room

Take the container with you to the hospital, if possible.

Your provider will measure and monitor your vital signs, including temperature, pulse, breathing rate, and blood pressure. Symptoms will be treated. You may receive:

• Activated charcoal
• Blood and urine tests
• Breathing support, including oxygen, or a tube that goes through the mouth into the lungs, and attachment to a breathing machine (ventilator)
• Chest (and possibly stomach) x-ray
• Electrocardiogram (ECG)
• Intravenous fluids (IV, given through a vein)
• Laxative
• Medicine to treat symptoms

Outlook (Prognosis)

With proper medical treatment, most people recover completely.

Death can occur from serious heart rhythm disturbances.

References

Meehan TJ. Care of the poisoned patient. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 135.

Nelson LS, Calello DP. Acute poisoning. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 96.

Pfennig CL, Slovis CM. Electrolyte disorders. In: Walls RM, ed. Rosen's Emergency Medicine: Concepts and Clinical Practice. 10th ed. Philadelphia, PA: Elsevier; 2023:chap 114.

Theobald JL, Corcoran JN. Poisoning. In: Kliegman RM, St. Geme JW, Blum NJ, et al, eds. Nelson Textbook of Pediatrics. 22nd ed. Philadelphia, PA: Elsevier; 2025:chap 94.

Review Date: 4/8/2025  

Reviewed By: Jesse Borke, MD, CPE, FAAEM, FACEP, Attending Physician at Kaiser Permanente, Orange County, CA. Also reviewed by David C. Dugdale, MD, Medical Director, Brenda Conaway, Editorial Director, and the A.D.A.M. Editorial team.

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