Low calcium tetany, hypoparathyroidism senile, osteoporosis, rickets and osteomalacia.
as phosphate binder in ESRD

Calcium plays an important role in neuromuscular activitiy, pancreatic insulin release, gastric hydrogen secretion, blood coagulation, and platelet aggregation. combines with dietary phosphate to form insoluble calcium phosphate which is excreted in feces

Oral absorption is about 30% and depends on vitamin D and parathyroid hormone
crosses the placenta, appears in breast milk
excreted mainly in feces as unabsorbed calcium with 20% eliminated by the kidneys

Patient receiving digitalis glycosides, or patients with ventricullar fibrillation or hypercalcemia;
calcium-phosphate producrt ﹥60-70 in the setting of uremia is associated with calcification in extraosseous tissues and should be avoided.

C

Calcium is excreted in breast milk with a significant loss seen during laction.

Soft-tissue calcification, venous thrombosis, arrhythmias, hypercalcemia may result in nephrolithiasis, anorexia, nausea, vomiting, and ocular toxicity.

Recommended daily allowance of elemental calcium:
adults: 1g,
children: 800mg,
infant 600 mg to lower serum phosphate in ESRD: 500 mg with each meal initially, adjust dosage to decrease serum phosphate to ﹤ 6mg/dLs.