Calcium 667mg typically refers to the elemental calcium content derived from calcium carbonate (1.67g, providing 667mg elemental calcium). It is an essential mineral supplement used to treat and prevent hypocalcemia and conditions associated with calcium deficiency. In the Indian context, it is widely used for bone health, particularly in postmenopausal women, the elderly, and individuals with dietary insufficiency.
Adult: 667 mg elemental calcium once or twice daily, usually with meals. For osteoporosis prevention/treatment: 1000-1200 mg total elemental calcium per day from all sources. The 667mg dose is often taken as one tablet.
Note: Take with or immediately after a meal to enhance absorption and reduce gastric irritation. Swallow whole with a full glass of water. Do not take within 2 hours of iron supplements, tetracycline, or fluoroquinolone antibiotics. For optimal absorption, single doses should not exceed 500-600mg; therefore, splitting the 667mg dose is advised but not always practical.
Calcium is the principal mineral component of bone (hydroxyapatite). It is essential for neuromuscular function, cardiac conduction, blood coagulation, and cellular signaling. As a supplement, it corrects negative calcium balance, suppresses bone resorption by reducing parathyroid hormone (PTH) secretion, and aids in bone mineralization.
Pregnancy: Category A (when used in recommended doses). Calcium requirements increase during pregnancy (1000-1300 mg/day). Supplementation may reduce risk of preeclampsia and preterm birth. Safe for use.
Driving: No effect on ability to drive or operate machinery.
| Bisphosphonates (Alendronate, Risedronate) | Calcium significantly reduces absorption of bisphosphonates. Administer at least 2 hours apart. | Major |
| Levothyroxine | Calcium carbonate impairs absorption. Administer at least 4 hours apart. | Major |
| Fluoroquinolones (Ciprofloxacin, Levofloxacin) & Tetracyclines (Doxycycline) | Chelation reduces antibiotic absorption. Administer 2-3 hours before or 4-6 hours after calcium. | Major |
| Iron Supplements | Mutual inhibition of absorption. Administer at least 2 hours apart. | Moderate |
| Thiazide Diuretics (Hydrochlorothiazide) | Increased risk of hypercalcemia due to reduced renal calcium excretion. | Moderate |
| Digoxin | Hypercalcemia can potentiate digoxin toxicity, leading to arrhythmias. | Major |
| Vitamin D or Calcitriol | Additive effect, increasing risk of hypercalcemia and hypercalciuria. | Moderate |
| Corticosteroids (Prednisolone) | Reduce calcium absorption, potentially increasing requirement. | Moderate |
Same composition (Calcium (667mg)), different brands: