calcium carbonate, Caltrate 600, Os-Cal 500, Tums Extra, Tums Chewy Delight, and Many Others (cont.)

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Medical and Pharmacy Editor:

PRESCRIBED FOR: Calcium-containing products are used as part of a regimen for preventing and treating osteoporosis in individuals with low levels of calcium in their diets. Calcium carbonate is also used as an antacid for treating minor stomach upset.


  • The usual recommended dose of calcium replacement is 1 to 1.2 g given daily in 2 or 4 divided doses with meals.
  • The dose for use as an antacid is 2 to 4 tablets per 24 hours not to exceed 7 g a day.

DRUG INTERACTIONS: Calcium can make it difficult for the body to absorb certain medications. Calcium products bind to quinolone (for example, ciprofloxacin) and tetracycline (for example, Sumycin) antibiotics in the intestine and can prevent their absorption into the body. To prevent this interaction, doses of quinolone and tetracycline antibiotics should be separated by three or more hours from doses of calcium.

Calcium carbonate-containing products reduce acidity in the stomach. The reduction of acid decreases the absorption of iron from the intestine. Therefore, doses of calcium and iron should be separated by a several hours.

Calcium products also bind to sodium polystyrene sulfonate (Kayexalate, a drug used to treat high levels of potassium) in the intestine and, therefore, may interfere with the action of Kayexalate. Doses of Kayexalate and calcium products should be separated by several hours.

PREGNANCY: Use of calcium supplements during pregnancy appears to be safe, but such use should be done under the supervision of a healthcare professional.

NURSING MOTHERS: Calcium products appear in breast milk but are considered safe during breastfeeding.

Calcium supplements are safe when used by nursing mothers.

Medically Reviewed by a Doctor on 7/31/2014

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