What is the recommended dosage and administration of calcium gluconate for treating hypocalcemia?

Calcium Gluconate Dosing and Administration for Hypocalcemia

For acute symptomatic hypocalcemia in adults, administer 1-2 grams of calcium gluconate IV infused over 30-60 minutes with continuous ECG monitoring; for pediatric patients, give 50-100 mg/kg IV (up to 60 mg/kg for mild cases) over 30-60 minutes. 1, 2

Dosing by Severity and Age

Adults

• Mild hypocalcemia (ionized calcium 1.0-1.12 mmol/L): 1-2 grams IV calcium gluconate over 30-60 minutes 1, 3
• Moderate to severe hypocalcemia (ionized calcium <1.0 mmol/L): 2-4 grams IV calcium gluconate over 30-60 minutes 1, 4
• Life-threatening arrhythmias: 100-200 mg/kg/dose via slow infusion with continuous ECG monitoring 1

Pediatric Patients

• Acute symptomatic hypocalcemia: 50-100 mg/kg IV infused slowly over 30-60 minutes with ECG monitoring 1
• Mild hypocalcemia: 60 mg/kg IV over 30-60 minutes 1

Neonates

• Contraindicated in neonates ≤28 days receiving ceftriaxone due to risk of fatal precipitates 2

Administration Guidelines

Route and Rate

• Administer via secure IV line, preferably central venous access to minimize risk of tissue necrosis from extravasation 1, 2
• Infusion rate: Maximum 1 gram/hour for non-emergent situations 3, 5, 4
• For cardiac arrest: Give as slow IV push 1
• Dilute with 5% dextrose or normal saline before administration 2

Critical Monitoring Requirements

• Continuous ECG monitoring during administration is mandatory 1, 2
• Stop infusion immediately if symptomatic bradycardia occurs or heart rate decreases by 10 beats per minute 1
• Measure ionized calcium every 4-6 hours during intermittent infusions 6, 2
• Measure ionized calcium every 1-4 hours during continuous infusions 6, 2

Maintenance Therapy for Severe Hypocalcemia

For ongoing severe hypocalcemia requiring continuous infusion, administer 1-2 mg elemental calcium per kg body weight per hour, adjusted to maintain ionized calcium 1.15-1.36 mmol/L (normal range). 6

• Monitor ionized calcium every 4-6 hours initially until stable, then twice daily 6
• Adjust infusion rate based on serial measurements 6

Special Clinical Situations

Calcium Channel Blocker Toxicity

• Administer 30-60 mL (3-6 grams) of 10% calcium gluconate IV every 10-20 minutes for hemodynamic instability 1
• Alternative: Continuous infusion at 0.6-1.2 mL/kg/hour (0.06-0.12 g/kg/hour) 1

Massive Transfusion/Trauma

• Target ionized calcium >0.9 mmol/L minimum to support cardiovascular function and coagulation 6
• Hypocalcemia results from citrate-mediated chelation from blood products 6
• Monitor continuously during ongoing transfusion 6

Hyperkalemia with Cardiac Manifestations

• Immediate IV calcium administration as part of standard ACLS care 1

Transition to Oral Therapy

When ionized calcium stabilizes and oral intake is possible, transition to calcium carbonate 1-2 grams three times daily. 6

• Consider adding calcitriol up to 2 μg/day to enhance intestinal absorption 6
• Total elemental calcium intake should not exceed 2,000 mg/day 6
• Monitor corrected total calcium and phosphorus at least every 3 months once stable 6

Essential Cofactor Correction

Always check and correct magnesium deficiency before expecting full calcium normalization, as hypomagnesemia is present in 28% of hypocalcemic ICU patients and prevents calcium correction. 6

• Administer IV magnesium sulfate for replacement in hypomagnesemic patients 6
• Hypocalcemia cannot be fully corrected without adequate magnesium 6

Critical Safety Considerations

Absolute Contraindications

• Hypercalcemia 2
• Neonates ≤28 days receiving ceftriaxone (risk of fatal precipitates) 2

Drug Incompatibilities

• Never mix with phosphate-containing fluids or bicarbonate - precipitation will occur 1, 2
• Do not administer through same line as sodium bicarbonate 1
• Do not mix with vasoactive amines 1

Cardiac Glycoside Interaction

• If patient is on digoxin or other cardiac glycosides, give calcium slowly in small amounts with close ECG monitoring due to synergistic arrhythmia risk 1, 2

Extravasation Risk

• Calcium gluconate is preferred over calcium chloride for peripheral administration to minimize vein irritation 1
• If extravasation occurs, immediately discontinue infusion at that site - can cause severe tissue necrosis, ulceration, and calcinosis cutis 2

Common Pitfalls to Avoid

• Do not rely on corrected total calcium alone - ionized calcium is more accurate in critically ill patients; adjusted calcium <2.2 mmol/L has only 78% sensitivity for predicting low ionized calcium 7
• Standard coagulation tests may appear normal despite significant hypocalcemia-induced coagulopathy because laboratory samples are citrated then recalcified before analysis 6
• Avoid rapid administration - can cause hypotension, bradycardia, and cardiac arrhythmias 2
• Exercise extreme caution in tumor lysis syndrome with elevated phosphate levels - calcium-phosphate precipitation can cause obstructive uropathy; consider renal consultation first 1
• Correction of acidosis may worsen hypocalcemia as acidosis increases ionized calcium levels 6

Product Information

• Concentration: 100 mg calcium gluconate per mL, containing 9.3 mg (0.4665 mEq) elemental calcium per mL 2
• Available as: Single-dose vials (10 mL, 50 mL) and pharmacy bulk package (100 mL) 2
• Contains aluminum up to 400 mcg/L - may be toxic with prolonged use 2