Calcium (250mg) is an essential mineral supplement, typically administered as calcium carbonate, citrate, or lactate, used to treat and prevent hypocalcemia and associated conditions. It is critical for bone mineralization, neuromuscular function, cardiac conduction, and blood coagulation. In the Indian context, it is widely used for osteoporosis management, pregnancy/lactation support, and as an adjunct in antacid therapy.
Adult: Prophylaxis: 250mg to 500mg elemental calcium 2-3 times daily. Treatment of Deficiency: 1-2g elemental calcium per day in divided doses (e.g., 250mg 4 times daily). Maximum daily intake from all sources should not exceed 2500mg.
Note: Take with or immediately after a meal to enhance absorption and reduce gastric irritation. Calcium carbonate requires stomach acid; take with food. Calcium citrate can be taken without food. Swallow whole with a full glass of water. Do not take within 2 hours of iron supplements, tetracyclines, fluoroquinolones, levothyroxine, or bisphosphonates.
Calcium is the primary mineral component of hydroxyapatite crystals, providing rigidity and strength to bones and teeth. Ionized calcium (Ca2+) in extracellular fluid is crucial for: 1) Stabilizing neuronal membranes and regulating neurotransmitter release. 2) Acting as an intracellular messenger for muscle contraction (via interaction with troponin C). 3) Serving as a cofactor for enzymes in the coagulation cascade (Factors IV, VII, IX, X). 4) Maintaining cardiac muscle contractility and automaticity. Supplementation corrects deficits, suppresses PTH secretion (secondary hyperparathyroidism), and reduces bone resorption.
Pregnancy: Category A (when used in recommended doses). Requirement increases to 1200-1500 mg/day. Essential for fetal skeletal development. Safe and recommended. Avoid megadoses (>2500mg/day).
Driving: No effect on driving ability.
| Levothyroxine | Calcium binds to levothyroxine in the gut, significantly reducing its absorption. | Major |
| Bisphosphonates (Alendronate, Risedronate) | Calcium (and other divalent cations) impair absorption of bisphosphonates. | Major |
| Fluoroquinolones (Ciprofloxacin, Levofloxacin) | Chelation reduces antibiotic absorption and efficacy. | Major |
| Tetracycline antibiotics | Chelation reduces antibiotic absorption and efficacy. | Major |
| Iron supplements | Mutual inhibition of absorption when taken together. | Moderate |
| Digoxin | Hypercalcemia potentiates digoxin effects, increasing risk of toxicity and arrhythmias. | Major |
| Thiazide diuretics | Reduce renal calcium excretion, increasing risk of hypercalcemia. | Moderate |
| Vitamin D analogues (Calcitriol) | Additive effect, significantly increasing risk of hypercalcemia and hypercalciuria. | Major |
| Corticosteroids | Reduce calcium absorption and increase excretion, potentially reducing efficacy. | Moderate |
Same composition (Calcium (250mg)), different brands: