Calcium carbonate

ATC code

A02AC01

Therapeutic class

Antacid, Calcium supplement · Calcium compound

Forms

oral tablet, chewable tablet

Brand names

ANTACID (US) · Tums (US) · Rennie (EU)

Overall confidence

medium

Regulatory sources consulted

openfda-label-60f41580-e08d-faad-e053-2a91aa0a9076
PubMed PMID:38892706 ↗
PubMed PMID:38180112 ↗
PubMed PMID:38467003 ↗
Clinical Pharmacology Knowledge
OpenFDA · A02AC01
RxNorm rxcui 1897 ↗
PubMed PMID:36976510 ↗

Approved indications

Relief of acid indigestion, heartburn, sour stomach, and upset stomach associated with these symptoms.
Prevention and treatment of calcium deficiency. Adjuvant in the prevention and treatment of osteoporosis.

Contraindications

Absolute

Hypercalcemia
Nephrolithiasis with calcium-containing stones

Relative

Severe renal failure

Clinical warnings

Major warning · Antacids may interact with certain prescription drugs by decreasing their absorption. — FDA
Major warning · Chronic use of high doses, especially with milk or dairy, can cause milk-alkali syndrome (hypercalcemia, metabolic alkalosis, renal failure). — Clinical Practice

Drug interactions

HighTetracyclines (e.g., Doxycycline)J01AA
Mechanism: Chelation of the antibiotic in the gastrointestinal tract, drastically reducing its absorption.
Recommendation: Administer calcium carbonate at least 2-3 hours before or after the tetracycline.
Clinical Pharmacology textbook
HighLevothyroxineH03AA01
Mechanism: Formation of an insoluble complex that reduces the absorption of the thyroid hormone.
Recommendation: Separate administration by at least 4 hours.
PMID:18392246
HighBisphosphonates (e.g., Alendronate)M05BA
Mechanism: Chelation in the gastrointestinal tract, significantly reducing the bioavailability of the bisphosphonate.
Recommendation: Take the bisphosphonate with water at least 30-60 minutes before any other food, drink, or medication, including calcium carbonate.
Drug interaction databases

Adverse events

Common (≥1%)

constipation · flatulence · belching · abdominal distension

Rare but serious

hypercalcemia · milk-alkali syndrome · nephrolithiasis

Pregnancy and lactation

FDA category: Not Assigned

Generally considered safe at recommended doses during pregnancy and lactation. Ask a health professional before use.

Recent literature (PubMed)

Long-Term Effect of Randomization to Calcium and Vitamin D Supplementation on Health in Older Women : Postintervention Follow-up of a Randomized Clinical Trial.
Thomson CA, et al. · Ann Intern Med · 2024 · Relevance 5/5
Seguimiento a largo plazo (22.3 años) del ensayo WHI en mujeres posmenopáusicas. La suplementación con calcio y vitamina D se asoció con una reducción del 7% en la mortalidad por cáncer, pero un aumento del 6% en la mortalidad cardiovascular, sin efecto sobre la mortalidad por todas las causas. Los resultados subrayan la complejidad de los efectos a largo plazo de la suplementación.
Nutrition, Vitamin D, and Calcium in Elderly Patients before and after a Hip Fracture and Their Impact on the Musculoskeletal System: A Narrative Review.
Cianferotti L, et al. · Nutrients · 2024 · Relevance 5/5
Revisión narrativa que destaca el papel fundamental de la nutrición, incluyendo calcio y vitamina D, en la prevención primaria y secundaria de fracturas de cadera en ancianos. Meta-análisis recientes confirman que la combinación de calcio y vitamina D reduce significativamente el riesgo de fractura de cadera, especialmente en personas mayores e institucionalizadas.
Population-based interventions for preventing falls and fall-related injuries in older people.
Lewis SR, et al. · Cochrane Database Syst Rev · 2024 · Relevance 3/5
Revisión Cochrane sobre intervenciones a nivel poblacional para prevenir caídas en personas mayores. Menciona políticas de suplementación con vitamina D (a menudo combinada con calcio) como una de las posibles estrategias comunitarias para reducir los factores de riesgo de caídas.