Dose and Administration

1. Urgent IV Correction ^{7, 13} : 0.23-0.46mmol/kg (1-2ml/kg of calcium gluconate 10%) by slow IV injection of diluted solution over 10 minutes.
   The infant requires ECG monitoring during the infusion.
2. Maintenance IV Treatment ^{6 , 11} :  0.5 - 1.0 mmol/kg/day as an IV infusion.
3. Oral ¹² :  1mmol/kg/day of elemental calcium in divided doses.

Indications ⁷

1. Treatment of symptomatic hypocalcaemia (serum Ca²⁺ <1.7mmol/L, ionised Ca²⁺ <0.64 mmol/L).

Contraindications ⁹

1. Hypercalcaemia.
2. Severe hypercalcuria.
3. Severe renal disease

Precautions ⁹

1. Impaired renal function
2. Cardiac disease
3. Diseases associated with elevated vitamin D concentrations.
4. Dehydration or electrolyte imbalance.

Clinical Pharmacology ⁹

Calcium activates many enzymatic reactions and is essential in a number of physiological processes including the transmission of nerve impulses; contraction of cardiac, smooth & skeletal muscle; renal function; respiration; and blood coagulation. Bone calcium is in constant exchange with plasma calcium. Bone contains 99% of the body calcium , with the remaining 1% distributed between the intracellular and extracellular fluids. If dietary deficiency, or other means, causes an imbalance of calcium in the body, the bone stores of calcium may be depleted to accommodate the body’s more acute needs. Ionised calcium is the physiologically active form of calcium. Approximately 45% of serum calcium is bound to plasma protein. Acidosis leads to increased levels of ionised calcium, and alkalosis decreases the levels. Calcium is excreted in the faeces as unabsorbed calcium, plus that excreted via the bile duct.

Possible Adverse Effects ^{7 ,8}

1. Extravasation of intravenous injection can cause cutaneous necrosis or calcium deposition.
2. Arrhythmias
3. Rapid administration is associated with bradycardia or cardiac asystole.
4. Gastric irritation and diarrhoea may occur during oral therapy.

Special Considerations ^{7 , 8}

1. Avoid intra-arterial and subcutaneous administration.  Never give intramuscularly.
2. Adjust dose in renal failure.
3. Monitor: plasma calcium
4. Late hypocalcaemia (4-10 days after birth) is usually associated with increased tone, jitteriness, and multiofcal seizures in an otherwise well infant.  Seizures are usually associated with serum Ca²⁺<1.7 mmol/L and ionised Ca²⁺<0.64mmol/L. Often there is hypomagnesaemia (Mg²⁺ <0.68mmol/L) and ECG changes (QT_c >0.2 sec).  In any infant presenting with late, symptomatic hypocalcaemia, consider investigation of maternal calcium homeostasis (especially hyperparathyroidism).
5. Treatment of asymptomatic neonatal hypocalcaemia is controversial.