Calcium gluconate | drug for hypocalcaemic tetany

Calcium gluconate | drug for hypocalcaemic tetany

Hypocalcaemia presents with symptoms ranging from paraesthesia and muscle cramps, to tetany with the classical features of carpo-pedal spasm, laryngeal stridor and convulsions. Calcium gluconate is a calcium supplement listed in the 2004 WHO Model Formulary as a complementary drug for the treatment of hypocalcaemic tetany

Calcium gluconate | drug for hypocalcaemic tetany

Therapeutic: mineral and electrolyte replacements/supplements


  • Asymptomatic or symptomatic hypocalcaemia.
  • Hyperkalaemia.
  • Exchange transfusion.
  • Magnesium toxicity.
  • Calcium channel blocker overdose.

Mechanism of action

Calcium is essential for the functional integrity of the nervous, muscular, skeletal and cardiac systems and for clotting function. It antagonises the cardiotoxic effects (arrhythmias) of hyperkalaemia, hypermagnesaemia and calcium channel blockers.


Hypocalcaemia, hyperkalaemia, magnesium toxicity, calcium channel blocker overdose IV or IO: Elemental Calcium – 0.15 mmol/kg (= 0.7mL/kg of UNDILUTRED 10% calcium gluconate). Repeat as necessary.

Maintenance IV calcium therapy – Titrate to serum calcium levels IV bolus: Elemental Calcium – 0.15 mmol/kg/dose 4-6 hourly (maximum daily dose 3 mmol/kg/day)

Exchange transfusion: Administer if hypocalcaemia:

IV: Elemental calcium 0.23 mmol/kg (= 1 mL/kg of UNDILUTED Calcium gluconate 10%); repeat as necessary.

Drug Interactions
Ceftriaxone (may cause insoluble precipitates and can be fatal), digoxin (serious risk of arrhythmia and cardiovascular collapse), thiazide diuretics (increased risk of hypercalcaemia), ketoconazole (decreased ketoconazole effect).

Chronic use with antacids in renal insufficiency may lead to milk-alkali syndrome. Ingestion bymouth decreases the absorption of orally administered tetracyclines, fluoroquinolones, phenytoin, and iron salts.

Excessive amounts may decrease the effects of calcium channel blockers. Decreases absorption of etidronate and risedronate (do not take within 2 hr of calcium supplements). May decrease the effectiveness of atenolol.

Concurrent use with diuretics (thiazide) may result in hypercalcemia. May decrease the ability of sodium polystyrene sulfonate to decrease serum potassium.

Drug-Food: Cereals, spinach, or rhubarb may decrease the absorption of calcium supplements. Calcium acetate should not be given concurrently with other calcium supplements.

Adverse Reactions
Rapid administration is associated with bradycardia or asystole. Rash, pain, burning at injection site, cutaneous necrosis with extravasation (give via central line unless otherwise instructed by a neonatologist) Nephrolithiasis with long-term use. Gastric irritation, diarrhoea and NEC have occurred during oral therapy with hyperosmolar preparations (must be diluted if used orally)

Fertility: No data available.

There is no information available on the use of calcium gluconate during pregnancy. The decision to treat pregnant women with calcium gluconate should therefore consider the potential benefits to the mother against the potential harm to the foetus.

Calcium crosses into the breast milk. Problems have not been documented with the administration of calcium to women who are breastfeeding. Nevertheless, the decision to treat breastfeeding mothers with calcium should weight the potential benefits to the mother against the potential harm to the infant.

Effects on ability to drive and use machinery: No data available.

Undesirable effects
Calcium salts are irritating to tissue when administered by intramuscular or subcutaneous injection and cause mild to severe local reactions including burning, necrosis and sloughing of tissue, cellulitis, and soft tissue calcification; venous irritation may occur with intravenous administration.

When injected intravenously, calcium salts should be administered slowly through a small needle into a large vein to avoid too rapid an increase in serum calcium and extravasation of calcium solution into the surrounding tissue with resultant necrosis. Patients may complain of tingling sensations, a sense of oppression or heat waves, and a calcium or chalky taste following intravenous administration of calcium salts.

Rapid intravenous injection of calcium salts may cause vasodilation, decreased blood pressure, bradycardia, cardiac arrhythmias, syncope, and cardiac arrest. Hypercalcemia is rarely produced by administration of calcium alone, but may occur when large doses are given to patients with chronic renal failure. Since hypercalcemia may be more dangerous than hypocalcemia, overtreatment of hypocalcemia should be avoided.


1. Do not give intra-arterially. Bolus infusions by UAC have been associated with intestinal bleeding and lower extremity tissue necrosis.

2. Rapid IV administration is associated with bradycardia, hypotension, cardiac arrhythmias or cardiac standstill. STOP infusion if heart rate drops below 100 bpm.

Contraindications and Precautions

1. CAUTION use with digitalized neonates – can precipitate digitalis toxicity 2. Do not administer intra-cardiac.



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