Calcium carbonate is a common supplement for people with low calcium levels. It can also be used as an antacid to control uncomfortable digestive symptoms.
Calcium carbonate (CaCO3) is a compound used as a dietary calcium supplement and a common antacid. It is one of the most abundant compounds in the earth's crust and occurs naturally in:
- Eggs and oyster shells
- crustacean exoskeleton
- Dark green leafy vegetables, such as kale
Calcium carbonate is available over-the-counter as a
- Rolaids and
- Pepto-Bismol et al.
Although calcium carbonate products and supplements are available without a prescription, correct dosage is important to get the most benefit and avoid possible complications.
What is calcium carbonate?
Calcium carbonate is a naturally occurring calcium salt commonly used as a food additive, antacid, phosphate binder, or dietary supplement.
As a medicine, it can help:
- Treat certain digestive problems (gastroesophageal reflux, acid reflux)
- Treat conditions associated with low calcium levels (osteoporosis, hypothyroidism)
- As a Phosphate Binder in Patients with Chronic Kidney Disease
Calcium carbonate supplements are available as tablets, chewable lozenges, oral suspensions, or powders. Your body gets the most calcium from powdered calcium carbonate, but other forms are also effective.
What are the uses of calcium carbonate?
This medication is used to treat symptoms caused by too much stomach acid, such as heartburn, stomach upset, or indigestion. It is an antacid that reduces stomach acid levels.
Calcium carbonate has a variety of medical uses. Although its best-known use is as an antacid, it can also be used to help control or prevent the following conditions:
- Low calcium levels (hypocalcemia): Calcium carbonate is a common ingredient in calcium supplements. Chronically low levels of calcium in the blood may be caused by conditions such as osteoporosis, hypothyroidism, and hypoparathyroidism.
- Gastroesophageal Reflux Disease and Heartburn: The antacid properties of calcium carbonate can relieve symptoms of digestive problems such as acid indigestion and heartburn. Calcium carbonate relieves symptoms by neutralizing the stomach acid that causes these symptoms.
- Chronic kidney disease: Calcium carbonate acts as a phosphate binder and may help prevent bone disease in people with kidney disease.
- Preeclampsia: Calcium supplementation can help reduce the risk of high blood pressure (preeclampsia) during pregnancy.
How much calcium carbonate should you take?
Calcium carbonate is generally considered safe as a daily calcium supplement.
But if you find yourself taking calcium carbonate regularly to relieve digestive problems, your doctor can help you investigate the root cause of your problem. Long-term use or abuse of antacids may have negative health effects.
The recommended dosage of calcium carbonate depends on your specific health needs. Experts generally recommend a daily supplement of no more than 500 milligrams (mg) of calcium carbonate because this is the amount that is best absorbed.
Doctors may recommend higher doses of calcium carbonate (up to 1,000 mg) for short-term use, but intake during this period should not exceed 8 grams per day.
How to use calcium carbonate tablets
Take this product by mouth as directed. For chewable tablet form, chew the medication well before swallowing. Available in liquid form, shake bottle well before each dose. Follow all directions on product packaging. Do not take more than the maximum recommended dose stated on the product packaging. If you have any questions, ask your doctor or pharmacist.
If your condition persists or worsens, tell your doctor. Do not take the maximum dose of this medication for more than 2 weeks unless directed by your doctor. If you think you may have a serious medical problem, seek medical assistance immediately.
Constipation, gas, and burping may occur.
Tell your doctor right away if you have any serious side effects, including:
- Loss of appetite,
- feel sick and vomit,
- Abnormal weight loss,
- bone/muscle pain,
- mental/emotional changes (e.g. delirium),
- Increased thirst/urination,
- Unusual weakness/tiredness,
- Signs of kidney problems (such as changes in urine output).
A very serious allergic reaction to this drug is rare. However, seek medical help immediately if you notice any symptoms of a serious allergic reaction, including:
- Itching/swelling (especially face/tongue/throat),
- severe dizziness,
- Difficulty breathing.
This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.
Before taking calcium carbonate, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients (such as milk or dairy products in some brands) that may cause allergic reactions or other problems. Ask your pharmacist for more details.
If you have any of the following health problems, consult your doctor or pharmacist before using this medication:
- high calcium levels (hypercalcemia),
- Stomach/intestinal obstruction,
- Kidney disease (such as kidney stones).
Some products may contain aspartame. If you have phenylketonuria (PKU) or any other condition that requires you to limit your intake of aspartame (or phenylalanine), ask your doctor or pharmacist about using this medication safely.
If you are pregnant, tell your doctor before using this medication.
This medication passes into breast milk. Please consult your doctor before breastfeeding.
Drug interactions may change how medications work or increase the risk of serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medications without your doctor's approval.
Some products that may interact with this drug include:
- Certain phosphate binders (such as calcium acetate),
- Phosphate supplements (such as potassium phosphate),
- Sodium polystyrene sulfonate.
Calcium carbonate can reduce the absorption of other medications. Some examples of affected drugs include:
- Tetracycline antibiotics (such as doxycycline, minocycline),
- Bisphosphonates (such as alendronate),
- Quinolone antibiotics (such as ciprofloxacin, levofloxacin), etc.
Separate doses of these drugs from doses of calcium carbonate as much as possible. Ask your doctor or pharmacist how long you should wait between doses, and get help finding a dosing schedule that works for all your medications.
Check the labels on all prescription and nonprescription/herbal products (e.g., supplements, vitamins) because they may contain calcium. Ask your pharmacist how to use these products safely.
If you don't get enough calcium through your diet or have a medical condition that causes low calcium levels in your body, calcium carbonate supplements are an effective way to increase your calcium levels.
Calcium carbonate is also used as an antacid to control symptoms of a variety of digestive problems and as a phosphate binder in patients with chronic kidney disease.
Although the side effects of calcium carbonate are usually mild, it is important to take only the recommended dosage to prevent any unintended health consequences.