Calcium Carbonate

ATC code

A12AA04

Therapeutic class

Mineral supplement · Calcium salt

Forms

powder for oral suspension, chewable tablet, oral tablet

Brand names

Caosina (ES) · Tums (US) · Caltrate (US) · Cacit (FR)

Overall confidence

medium

Regulatory sources consulted

AEMPS CIMA FT 29243: https://cima.aemps.es/cima/dochtml/ft/29243/FT_29243.html
General Clinical Pharmacology Knowledge
AEMPS CIMA · nº registro 29243 ↗

Approved indications

Treatment of calcium deficiency states.
Coadjuvant treatment in osteoporosis (senile, postmenopausal, corticosteroid-induced).
Treatment of hyperphosphatemia in chronic renal failure (as a phosphate binder).
Symptomatic relief of heartburn and acid indigestion.

Contraindications

Absolute

Hypersensitivity to the active substance.
Hypercalcemia and hypercalciuria.
Nephrolithiasis (calcium stones).

Clinical warnings

Major warning · Risk of hypercalcemia, especially in patients with renal impairment or with concomitant intake of high doses of vitamin D. Serum calcium levels should be monitored. — AEMPS CIMA
Prolonged use of high doses with absorbable alkali (such as bicarbonate) can lead to milk-alkali syndrome. — AEMPS CIMA

Drug interactions

HighLevothyroxineH03AA01
Mechanism: Formation of insoluble complexes (chelation) in the gastrointestinal tract, significantly reducing levothyroxine absorption.
Recommendation: Administer levothyroxine at least 4 hours before or 4 hours after calcium carbonate administration.
AEMPS CIMA
HighTetracyclines and QuinolonesJ01A
Mechanism: Calcium forms chelates with tetracycline and quinolone antibiotics, decreasing their gastrointestinal absorption and efficacy.
Recommendation: Administer the antibiotic 2 hours before or 4-6 hours after the calcium supplement.
AEMPS CIMA
ModerateThiazide diureticsC03A
Mechanism: Thiazide diuretics reduce urinary calcium excretion, increasing the risk of hypercalcemia when administered with calcium supplements.
Recommendation: Monitor serum calcium levels in patients receiving concomitant therapy.
AEMPS CIMA

Adverse events

Common (≥1%)

constipation · flatulence · nausea · abdominal pain · belching

Rare but serious

hypercalcemia · milk-alkali syndrome · nephrolithiasis

Pregnancy and lactation

Can be used during pregnancy and lactation in case of calcium deficiency. However, the daily intake should not exceed 2500 mg of calcium carbonate (1000 mg of elemental calcium). Hypercalcemia during pregnancy may produce adverse effects on the developing fetus.