What is the dosage and administration of calcium gluconate (Ca gluconate) injection for treating hypocalcemia?

Calcium Gluconate Injection Dosage for Hypocalcemia

For treating hypocalcemia, administer 10% calcium gluconate intravenously at a dose of 1-2 g (10-20 mL) for mild hypocalcemia and 2-4 g for moderate to severe hypocalcemia, diluted in 5% dextrose or normal saline, infused at a rate not exceeding 200 mg/minute while monitoring cardiac rhythm. 1, 2

Dosage Specifications

Adult Patients:

• Mild hypocalcemia (iCa 1.0-1.12 mmol/L): 1-2 g IV calcium gluconate 3
  • Effective in normalizing calcium in approximately 79% of patients
• Moderate to severe hypocalcemia (iCa <1.0 mmol/L): 2-4 g IV calcium gluconate 4
  • 4 g infusion achieves normalization in 95% of patients with moderate to severe hypocalcemia

Pediatric Patients:

• Calcium gluconate: 60 mg/kg IV 5, 1
• For symptomatic pediatric patients: 50-100 mg/kg IV administered slowly with ECG monitoring 5

Administration Guidelines

Preparation:

• 10% calcium gluconate contains 9.3 mg (0.465 mEq) of elemental calcium per mL 1, 2
• A 10-mL ampule of 10% calcium gluconate contains 90 mg of elemental calcium 1

Administration Rate:

• Administer via secure intravenous line 2
• For cardiac arrest: Give by slow push 5
• For other indications: Infuse over 30-60 minutes 5
• Do not exceed 200 mg/minute infusion rate 1
• For moderate to severe hypocalcemia: Infuse at 1 g/hour 4

Route Considerations:

• Administration through a central venous catheter is preferred 5, 1
• Extravasation through a peripheral IV line may cause severe skin and soft tissue injury 5

Monitoring

• Continuous cardiac monitoring is essential during calcium administration 1
• Stop injection if symptomatic bradycardia occurs 5, 1
• Measure serum calcium during intermittent infusions every 4-6 hours 2
• During continuous infusion, monitor serum calcium every 1-4 hours 2

Important Precautions

Drug Incompatibilities:

• Calcium gluconate is not physically compatible with fluids containing phosphate or bicarbonate 2
• Do not mix with ceftriaxone, solutions containing bicarbonate or phosphate, or minocycline injection 1
• Do not mix sodium bicarbonate with vasoactive amines or calcium 5

Special Considerations:

• Use caution when administering calcium in patients with hyperphosphatemia due to risk of calcium phosphate precipitation 5, 1
• Consider treating hyperphosphatemia first with phosphate binders if phosphate levels are significantly elevated 1
• For patients with concomitant cardiac glycoside use, administer calcium slowly in small amounts with close ECG monitoring 2
• Calcium chloride contains more elemental calcium (270 mg per 10 mL of 10% solution) compared to calcium gluconate (90 mg per 10 mL of 10% solution) and may be preferred in critically ill patients 1

Clinical Efficacy

• Treatment with 1-2 g IV calcium gluconate normalizes calcium in 79% of patients with mild hypocalcemia 3
• For moderate to severe hypocalcemia, 4 g calcium gluconate infusion achieves normalization in 95% of patients 4
• Hypocalcemia typically normalizes within the first four days after ICU admission 6
• Failure to normalize calcium levels in severely hypocalcemic patients may be associated with increased mortality 6

Common Pitfalls

• Relying on adjusted calcium (AdjCa) rather than ionized calcium (iCa) for diagnosis and monitoring (AdjCa<2.2 mmol/L has only 78.2% sensitivity and 63.3% specificity for predicting iCa<1.1 mmol/L) 6
• Administering calcium too rapidly, which can cause hypotension, bradycardia, and cardiac arrhythmias 1, 2
• Using calcium gluconate in patients with hypercalcemia (contraindicated) 2
• Failing to monitor for aluminum toxicity with repeated administration, as calcium gluconate contains up to 400 mcg of aluminum per liter 2