Classifications: fluid and electrolytic and water balance agent; replacement solution
Pregnancy Category: B


500 mg, 650 mg, 975 mg, 1 gm tablets; 10% injection


Calcium is an essential element for regulating the excitation threshold of nerves and muscles, for blood clotting mechanisms, cardiac function (rhythm, tonicity, contractility), maintenance of renal function, for body skeleton and teeth. Also plays a role in regulating storage and release of neurotransmitters and hormones; regulating amino acid uptake and absorption of vitamin B12, gastrin secretion, and in maintaining structural and functional integrity of cell membranes and capillaries. Calcium gluconate acts like digitalis on the heart, increasing cardiac muscle tone and force of systolic contractions (positive inotropic effect).

Therapeutic Effects

Rapidly and effectively restores serum calcium levels in acute hypocalcemia of various origins and effective cardiac stabilizer under conditions of hyperkalemia or resuscitation.


Negative calcium balance (as in neonatal tetany, hypoparathyroidism, vitamin D deficiency, alkalosis). Also to overcome cardiac toxicity of hyperkalemia, for cardiopulmonary resuscitation, to prevent hypocalcemia during transfusion of citrated blood. Also as antidote for magnesium sulfate, for acute symptoms of lead colic, to decrease capillary permeability in sensitivity reactions, and to relieve muscle cramps from insect bites or stings. Oral calcium may be used to maintain normal calcium balance during pregnancy, lactation, and childhood growth and to prevent primary osteoporosis. Also in osteoporosis, osteomalacia, chronic hypoparathyroidism, rickets, and as adjunct in treatment of myasthenia gravis and Eaton-Lambert syndrome.

Unlabeled Uses

To antagonize aminoglycoside-induced neuromuscular blockage, and as "calcium challenge" to diagnose Zollinger-Ellison syndrome and medullary thyroid carcinoma.


Ventricular fibrillation, metastatic bone disease, injection into myocardium; administration by SC or IM routes; renal calculi, hypercalcemia, predisposition to hypercalcemia (hyperparathyroidism, certain malignancies); pregnancy (category B).

Cautious Use

Digitalized patients, renal or cardiac insufficiency, sarcoidosis, history of lithiasis, immobilized patients; lactation.

Route & Dosage

All doses are in terms of elemental calcium: 1 g calcium gluconate = 90 mg (4.5 mEq, 9.3%) elemental calcium

Supplement for Osteoporosis
Adult: PO 1–2 g b.i.d. to q.i.d. IV 7 mEq q1–3d
Child: PO 45–65 mg/kg/d in divided doses. IV 1–7 mEq q1–3d
Neonate: PO 50–130 mg/kg/d (max: 1 g) IV mEq q1–3d

Hypocalcemic Tetany
Adult: IV 4.5–16 mEq prn
Child: IV 0.5–0.7 mEq/kg t.i.d. or q.i.d.
Neonate: IV 2.4 mEq/kg/d in divided doses

Adult: IV 2.3–3.7 mEq x 1

Hyperkalemia with Cardiac Toxicity
Adult: IV 2.25–14 mEq q 1–2 min

Exchange Transfusions with Citrated Blood
Adult: IV 1.35 mEq for each 100 mL of blood
Neonate: IV 0.45 mEq for each 100 mL of blood



PREPARE: Direct: May be given undiluted  Intermittent/Continuous: May be diluted in 1000 mL of NS.  

ADMINISTER: Direct: Give direct IV at a rate of 0.5 mL or a fraction thereof over 1 min. Do not exceed 2 mL/min.  Intermittent/Continuous: Give slowly, not to exceed 200 mg/min, through a small-bore needle into a large vein to avoid possibility of extravasation and resultant necrosis. With children, scalp veins should be avoided. Avoid rapid infusion. High concentrations of calcium suddenly reaching the heart can cause fatal cardiac arrest.  

INCOMPATIBILITIES Solution/additive: Amphotericin B, cefamandole, dobutamine, methylprednisolone, metoclopramide, concentration-dependent incompatibility with other electrolytes. Y-site: Amphotericin B cholesteryl complex, fluconazole, indomethacin.

  • Injection should be stopped if patient complains of any discomfort.
  • Patient should be advised to remain in bed for 15–30 min or more following injection, depending on response.

Adverse Effects (1%)

Body as a Whole: Tingling sensation. With rapid IV, sensations of heat waves (peripheral vasodilation), fainting. GI: PO preparation: Constipation, increased gastric acid secretion. CV: (With rapid infusion) hypotension, bradycardia, cardiac arrhythmias, cardiac arrest, Skin: Pain and burning at IV site, severe venous thrombosis, necrosis and sloughing (with extravasation).

Diagnostic Test Interference

IV calcium may cause false decreases in serum and urine magnesium (by Titan yellow method) and transient elevations of plasma 11-OHCS levels by Glenn-Nelson technique. Values usually return to control levels after 60 min; urinary steroid values (17-OHCS) may be decreased.


Drug: May enhance inotropic and toxic effects of digoxin; magnesium may compete for GI absorption; decreases absorption of tetracyclines, quinolones (ciprofloxacin); antagonizes the effects of verapamil and possibly other calcium channel blockers (IV administration).


Absorption: Approximately 1/3 of dose absorbed from small intestine. Onset: Immediately after IV. Distribution: Crosses placenta. Elimination: Primarily excreted in feces; small amounts excreted in urine, pancreatic juice, saliva, and breast milk.

Nursing Implications

Assessment & Drug Effects

Patient & Family Education

Common adverse effects in italic, life-threatening effects underlined; generic names in bold; classifications in SMALL CAPS; Canadian drug name; Prototype drug