Calcium Gluconate

Pronunciation: KAL-see-um GLOO-koe-nate
Class: Mineral

Trade Names

Calcium gluconate
- Tablets 300 mg
- Tablets 500 mg
- Tablets 555.6 mg
- Tablets 648 to 650 mg
- Tablets 972 to 975 mg
- Powder 346.7 mg per 3.9 g (1 Tbsp)
- Injection 10% (elemental calcium 9.3 mg per mL)

Cal-G
- Capsules 700 mg

Cal-GLU
- Capsules 515 mg

Calgonate
- Gel 2.5%

Pharmacology

Essential for maintenance of the functional integrity of nervous, muscular, and skeletal systems and cell membrane and capillary permeability. It is also an important activator in many enzymatic reactions and is essential to a number of physiologic processes, including transmission of nerve impulses; contraction of cardiac, smooth, and skeletal muscles; renal function; respiration; and blood coagulation. Calcium also plays regulatory roles in the release and storage of neurotransmitters and hormones, in the uptake and binding of amino acids, and in cyanocobalamin (vitamin B ₁₂ ) absorption and gastrin secretion. 1 g (10 mL) of calcium gluconate 10% contains 93 mg (4.65 mEq) calcium.

Pharmacokinetics

Absorption

Oral absorption occurs primarily from the small intestine by active transport and passive diffusion and is enhanced by calcitriol, a vitamin D metabolite.

Elimination

Excess calcium is primarily excreted renally while unabsorbed calcium is excreted in the feces along with that secreted in the bile and pancreatic juice.

Indications and Usage

Parenterally, as treatment of hypocalcemic tetany, hypocalcemia related to hypoparathyroidism, and hypocalcemia caused by rapid growth or pregnancy; treatment of hyperkalemia-induced cardiac toxicity, provided the patient is not receiving digitalis therapy; to decrease capillary permeability in allergic conditions, nonthrombocytopenic purpura, and exudative dermatoses, such as dermatitis herpetiformis, and for pruritus of eruptions caused by certain drugs; treatment of black widow spider bites to relieve muscle cramping; adjunctive treatment of rickets, osteomalacia, lead colic, and magnesium sulfate overdosage. Orally as a dietary supplement.

Contraindications

Hypercalcemia; ventricular fibrillation.

Dosage and Administration

Adults

PO 500 to 8,000 mg/day (as calcium gluconate), in divided doses, preferably 1 to 2 h after meals. For the powder, 3 Tbsp/day with food or liquid. IV 500 mg to 2 g (5 to 20 mL of 10% solution).

Children

IV 200 to 500 mg (2 to 5 mL of 10% solution).

Infants

IV No more than 200 mg (no more than 2 mL of 10% solution).

General Advice

• Administer tablets or capsules 1 to 2 h after meals.
• Administer powder with food or liquid.
• Injection is for IV use. Do not give by IM or subcutaneous route.
• Administer slowly. Rapid injection may cause cardiac arrest.
• May administer by intermittent infusion (up to 200 mg/min) or by continuous infusion.
• Administer through a small needle into a large vein.
• Take caution to prevent perivascular leakage.
• If crystallization has occurred, warming in a 60°C water bath for 15 to 30 min with occasional shaking may dissolve the precipitate. Cool to body temperature before use. The injection must be clear at the time of use.

Storage/Stability

Store at 15° to 30°C (59° to 86°F). Do not freeze. Do not expose oral products to excessive heat or moisture.

Drug Interactions

Atenolol, bisphosphonates (eg, alendronate, risedronate), tetracyclines

May decrease oral absorption of these drugs.

Cardiac glycosides (eg, digoxin)

May potentiate digitalis and calcium toxicities.

Ceftriaxone

Do not mix or administer with ceftriaxone.

Proton pump inhibitors (eg, omeprazole)

May reduce calcium absorption.

Tetracyclines

Do not mix with tetracyclines.

Thiazide diuretics (eg, hydrochlorothiazide)

May cause possible calcium toxicity and hypercalcemia.

Verapamil

May reverse clinical effects and toxicities of verapamil.

Laboratory Test Interactions

Parenteral calcium gluconate may produce false-negative values for serum and urinary magnesium. Transient elevations of plasma II-hydroxy-corticosteroid levels (Glenn-Nelson technique) may occur.

Adverse Reactions

CNS

Sense of oppression.

GI

Calcium or chalky taste in mouth, GI irritation.

Miscellaneous

Sensation of heat waves, tingling sensation.

Precautions

Monitor Monitor plasma calcium levels closely in patients with renal function impairment and/or if large doses of vitamin D are used concurrently.

Pregnancy

Category C .

Lactation

Excreted in breast milk.

Children

Premature neonates are at particular risk of aluminum toxicity.

Renal Function

Use with caution. Avoid use in patients with calcium renal calculi or a history of renal calculi. Aluminum toxicity may occur in patients with impaired kidney function, including premature neonates.

Special Risk Patients

Use cautiously in patients with diseases associated with hypercalcemia, such as sarcoidosis and some malignancies.

Administration

Rapid IV injection may cause vasodilation, decreased blood pressure, bradycardia, cardiac arrhythmias, syncope, and cardiac arrest. Local necrosis and abscess formation may occur with IM injection.

Aluminum toxicity

Parenteral products may contain aluminum that may be toxic.

Digitized patients

Use may precipitate arrhythmias.

Hypercalcemia

Avoid overtreatment of hypocalcemia because hypercalcemia may be more dangerous than hypocalcemia.

Hypocalcemic tetany

Other therapy, such as parathyroid hormone or vitamin D, may be indicated according to the etiology of the tetany.

Overdosage

Symptoms

Hypercalcemia with symptoms of abdominal pain, anorexia, constipation, mental disturbances, muscle weakness, nausea, nephrocalcinosis, polydipsia, polyuria, renal calculi, and vomiting. Severe cases of hypercalcemia may cause cardiac arrhythmias and coma.

Patient Information

• Advise patient to take tablets or capsules 1 to 2 h after meals.
• Advise patient to take oral suspension with food or liquid.
• Advise patient, family, or caregiver that parenteral medication will be prepared and administered by health care provider in a health care setting.
• Advise patient, family, or caregiver to immediately report any of the following to health care provider: general body weakness, injection-site reaction or pain, intractable nausea and vomiting.

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