Treatment of Ca deficiencies due to tetany, hypoparathyroidism, rapid growth or pregnancy. Treatment of black widow spider bites; adjunct in treatment of rickets, osteomalacia, lead colic & Mg sulfate overdosage; decrease capillary permeability in allergic conditions, non-thrombocytopenic purpura & exudative dermatoses; aid in antagonizing cardiac toxicity associated w/ hyperkalemia provided patient is not on digitalis.