Adult: 0.5-3 g as symptoms occur. Max: 8 g daily for up to 2 weeks. Dosage recommendations may vary among individual products and between countries (refer to detailed product guideline). Child: 2-5 years 0.375-0.4 g as symptoms occur. Max: 1.5 g daily for up to 2 weeks; 6-11 years 0.75-0.8 g as symptoms occur. Max: 3 g daily for up to 2 weeks; ≥12 years 0.5-3 g as symptoms occur. Max: 7.5 g daily for up to 2 weeks. Dosage recommendations may vary among individual products and between countries (refer to detailed product guideline).
Oral Calcium deficiency
Adult: 0.5-4 g daily in 1-3 divided doses. Dosage recommendations may vary among individual products and between countries (refer to detailed product guideline). Child: 2-4 years 750 mg bid; ≥4 years 750 mg tid. Dosage recommendations may vary among individual products and between countries (refer to detailed product guideline).
Oral Hyperphosphataemia in patients with chronic renal failure
Adult: 3-7 g daily in divided doses. Adjust according to patient’s serum phosphate level.
Renal Impairment
Calcium deficiency; Hyperacidity:
CrCl (mL/min)
Dosage
<25
Dosage adjustment may be needed based on serum Ca levels.
Administration
May be taken with or without food. Take w/ meals for better absorption. Avoid taking w/ large amount of fibre-rich food.
Contraindications
Hypercalcaemia resulting from myeloma, bone metastases or other malignant bone disease, sarcoidosis, primary hyperparathyroidism, vitamin D overdosage. Osteoporosis due to long term immobilisation, severe hypercalciuria, kidney stones. Severe renal failure untreated by renal dialysis.
Special Precautions
Patient with achlorhydria, hypoparathyroid disease; history of kidney stones. Renal impairment. Pregnancy and lactation.
Monitor serum and urinary Ca levels, and kidney function in long term treatment.
Overdosage
Symptoms: Anorexia, thirst, nausea, vomiting, constipation, abdominal pain, muscle weakness, fatigue, mental disturbances, polydipsia, polyuria, bone pain, nephrolithiasis and cardiac arrhythmia in severe cases. Management: Discontinue Ca treatment. Ca levels should be lowered through high fluid intake and low Ca diet. For severe cases, treatments with corticosteroids may be necessary.
Drug Interactions
Increased risk of hypercalcaemia with thiazide diuretics. May enhance the effect of cardiac glycosides (e.g. digoxin). May reduce the absorption of thyroxine, bisphosphonates, Na fluoride, antibiotics (quinolone, tetracycline), and Fe. Systemic corticosteroids may reduce Ca absorption.
Food Interaction
Food may increase Ca absorption. Bran, foods high in oxalates, or whole grain cereals may decrease Ca absorption.
Action
Description: Mechanism of Action: Calcium carbonate is used as a supplementary source of Ca to help prevent or decrease the rate of bone loss in osteoporosis. It also acts as an antacid by neutralising gastric acidity resulting in increased gastric and duodenal pH. Additionally, it is also used in the treatment of hyperphosphatemia in patients with chronic kidney disease by binding with phosphate in the gastrointestinal tract to form insoluble complex thus reducing phosphate absorption. Pharmacokinetics: Absorption: Absorbed from the gastrointestinal tract, predominantly in the duodenum. Distribution: Primarily in bones and teeth. Crosses the placenta, enters breast milk. Plasma protein binding: Approx 40%, to albumin. Metabolism: Converted to Ca chloride by gastric acid. Excretion: Mainly via faeces (75% as unabsorbed Ca); urine (22%).
Chemical Structure
Calcium carbonate Source: National Center for Biotechnology Information. PubChem Database. Calcium carbonate, CID=10112, https://pubchem.ncbi.nlm.nih.gov/compound/Calcium-carbonate (accessed on Jan. 21, 2020)
A12AA04 - calcium carbonate ; Belongs to the class of calcium-containing preparations. Used as dietary supplements. A02AC01 - calcium carbonate ; Belongs to the class of calcium-containing antacids.
References
Adcal 1,500 mg Chewable Tablet (Kyowa Kirin Limited). MHRA. https://products.mhra.gov.uk. Accessed 02/02/2021.Anon. Calcium Carbonate. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 02/02/2021.Buckingham R (ed). Calcium Carbonate. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 02/02/2021.Calcium Carbonate Suspension (Pharmaceutical Associates, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 02/02/2021.Calcium Carbonate Tablets (GlaxoSmithKline Consumer Healthcare [UK] Trading Limited). MHRA. https://products.mhra.gov.uk. Accessed 02/02/2021.
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