Kalcijev Karbonat Lekarna Ljubljana (Calcium Carbonate)

Calcium carbonate is used as a calcium supplement to correct deficiencies and support skeletal health.

• Calcium deficiency: helps restore normal serum calcium concentrations.
• Osteoporosis prevention: provides elemental calcium needed for bone mineralization, reducing bone loss risk.
• Hypocalcemia: supplies calcium to raise low blood calcium levels in acute settings.
• General bone health: contributes to maintaining adequate calcium intake for adults with low dietary calcium.
• Post‑menopausal women: supports calcium requirements to mitigate accelerated bone turnover.
• Renal osteodystrophy: assists in managing calcium balance in chronic kidney disease patients.

• Calcium carbonate dissociates in the acidic environment of the stomach, releasing elemental calcium ions. These ions are absorbed primarily in the duodenum and jejunum via active transport mechanisms that are enhanced by vitamin D. The absorbed calcium is incorporated into hydroxyapatite crystals, strengthening bone matrix, while excess carbonate can neutralize gastric acid, providing antacid effect. The systemic increase in calcium contributes to various physiological processes, including muscle contraction and nerve transmission.

Calcium carbonate may cause a range of adverse reactions, from mild gastrointestinal discomfort to rare serious events.

Common Side Effects

• Constipation: hard stools and difficulty passing bowel movements.
• Flatulence: increased gas production leading to bloating.
• Nausea: feeling of unease and urge to vomit.
• Abdominal discomfort: mild pain or cramping in the stomach area.
• Belching: release of gas from the stomach through the mouth.
• Diarrhea: loose, watery stools in some individuals.

Serious or Rare Side Effects

• Hypercalcemia: elevated blood calcium levels that can cause confusion, cardiac arrhythmia, or kidney dysfunction.
• Kidney stones: formation of calcium‑containing calculi in the urinary tract.
• Severe allergic reaction: rash, itching, swelling, or difficulty breathing.
• Acute pancreatitis: sudden inflammation of the pancreas, presenting with severe abdominal pain.

Before using calcium carbonate, consider the following precautions to ensure safe and effective therapy.

• Assess calcium needs: evaluate dietary intake and serum calcium levels.
• Monitor for hypercalcemia: periodic blood tests are advised in high‑risk patients.
• Renal impairment caution: adjust dose or avoid in severe kidney disease.
• Concomitant vitamin D: avoid excessive combined calcium and vitamin D supplementation without medical guidance.
• Drug absorption interactions: separate administration from bisphosphonates, iron, or certain antibiotics by at least 2 hours.
• Store at ambient temperature: keep in the original container, protect from moisture and direct sunlight.

Calcium carbonate can affect the absorption or action of several medicines; awareness of these interactions helps prevent therapeutic failures.

Major Interactions (Avoid)

• Bisphosphonates: calcium binds and markedly reduces their oral absorption.
• Iron salts: concurrent intake decreases iron absorption, lowering efficacy.
• Tetracycline antibiotics: calcium chelation impairs antibiotic absorption.
• Quinolone antibiotics: reduced bioavailability when taken with calcium carbonate.
• Levothyroxine: calcium interferes with thyroid hormone absorption.

Moderate Interactions (Monitor Closely)

• Vitamin D analogues: combined use may increase risk of hypercalcemia; monitor serum calcium.
• Thiazide diuretics: may enhance calcium retention, requiring periodic calcium level checks.
• Loop diuretics: can cause calcium loss; monitor balance when both are used.