A fixed-dose combination supplement containing elemental calcium (as calcium carbonate) and cholecalciferol (Vitamin D3). Calcium is a critical mineral for bone mineralization, muscle contraction, nerve transmission, and blood coagulation. Vitamin D3 enhances intestinal absorption of calcium and phosphate, regulates bone remodeling, and supports immune function. This combination is fundamental for maintaining skeletal health and preventing/treating deficiencies, particularly relevant in the Indian population due to widespread dietary insufficiency, cultural practices limiting sun exposure, and high prevalence of osteopenia and osteoporosis.
Adult: One tablet (500mg Calcium + 250IU Vit D3) once or twice daily, preferably with meals. For osteoporosis, typically one tablet twice daily.
Note: Take with or immediately after a meal to enhance calcium absorption and reduce gastric upset. Swallow whole with a full glass of water. Do not take with high-fiber meals or foods containing oxalic acid (spinach) or phytic acid (whole grains) as they can bind calcium. Space by at least 2 hours from iron supplements, tetracyclines, or fluoroquinolones.
The combination works synergistically. Calcium provides the essential mineral ion required for hydroxyapatite crystal formation in bone matrix. Vitamin D3, via its active metabolite calcitriol, acts on the intestinal epithelial cells to increase the expression of calcium-binding proteins (calbindin-D), facilitating active transcellular absorption of calcium. It also promotes renal tubular reabsorption of calcium and phosphate and, in conjunction with PTH, stimulates bone resorption to mobilize calcium when needed.
Pregnancy: Category A (Australian categorization) / Generally considered safe. Requirements increase during pregnancy (RDA: 1000-1300 mg Calcium, 600 IU Vit D). Use under medical supervision. Essential for fetal skeletal development.
Driving: No known effects on driving ability.
| Thiazide Diuretics (e.g., Hydrochlorothiazide) | Reduce renal calcium excretion, increasing risk of hypercalcemia. | Major |
| Bisphosphonates (e.g., Alendronate) | Calcium supplements interfere with absorption. Administer at least 2 hours apart. | Moderate |
| Levothyroxine | Calcium carbonate can decrease its absorption. Administer at least 4 hours apart. | Moderate |
| Oral Corticosteroids (e.g., Prednisolone) | Reduce calcium absorption and increase excretion, counteracting the supplement's effect. | Moderate |
| Digoxin | Hypercalcemia potentiates digoxin toxicity, increasing risk of cardiac arrhythmias. | Major |
| Oral Quinolones/Tetracyclines (e.g., Ciprofloxacin, Doxycycline) | Calcium binds to these antibiotics, forming insoluble complexes and reducing their absorption. | Moderate |
| Orlistat | May reduce absorption of fat-soluble Vitamin D3. | Moderate |
| Phenytoin, Phenobarbital, Carbamazepine | Induce hepatic CYP450 enzymes, accelerating metabolism of Vitamin D3 to inactive metabolites, reducing efficacy. | Moderate |
Same composition (Calcium (500mg) + Vitamin D3 (250IU)), different brands: