How should I prepare a calcium gluconate intravenous infusion for an adult requiring rapid calcium replacement (e.g., symptomatic hypocalcemia, hyperkalemia, calcium‑channel‑blocker toxicity)?

How to Prepare a Calcium Gluconate Intravenous Infusion

For adult patients requiring rapid calcium replacement, dilute 10 vials (100 mL) of 10% calcium gluconate in 1 liter of normal saline or 5% dextrose and infuse at 50–100 mL/hour via a secure intravenous line with continuous ECG monitoring. 1

Preparation and Dilution

Standard Concentration

• Each 10 mL vial of 10% calcium gluconate contains 2.2 mmol (or 9.3 mg/mL) of elemental calcium. 2, 1
• For continuous infusion, dilute 100 mL of 10% calcium gluconate (10 vials) in 1 liter of normal saline or 5% dextrose. 1
• This creates a maintenance infusion that delivers approximately 1.1–2.2 mmol of calcium per hour when infused at 50–100 mL/hour. 1

Critical Incompatibilities

• Never mix calcium gluconate with phosphate-containing fluids or sodium bicarbonate—precipitation will occur immediately. 3, 2
• Do not administer through the same IV line as sodium bicarbonate or vasoactive amines (epinephrine, dopamine, norepinephrine). 3, 2

Initial Bolus Dosing by Clinical Scenario

Symptomatic Hypocalcemia (Tetany, Seizures, Severe Symptoms)

• Administer 10–20 mL of 10% calcium gluconate diluted in 50–100 mL of 5% dextrose or normal saline, infused over 10 minutes with continuous ECG monitoring. 1
• For adults, the dose range is 1–2 grams (10–20 mL of 10% solution) given slowly. 3
• This bolus can be repeated every 10–20 minutes until symptoms resolve. 1

Calcium Channel Blocker Toxicity

• Give 30–60 mL (3–6 grams) of 10% calcium gluconate IV every 10–20 minutes, or initiate a continuous infusion at 0.6–1.2 mL/kg/hour (0.06–0.12 g/kg/hour). 4, 3
• Calcium gluconate is preferred over calcium chloride to minimize peripheral vein irritation in this setting. 4, 3

Hyperkalemia with Cardiac Manifestations

• Administer 10 mL of 10% calcium gluconate IV over 2–10 minutes with continuous ECG monitoring for membrane stabilization. 3, 5
• This dose provides cardioprotection but does not lower serum potassium; it must be followed by potassium-lowering therapies. 5

Life-Threatening Arrhythmias or Cardiac Arrest

• In cardiac arrest, calcium chloride (10 mL of 10% solution) is preferred over calcium gluconate because it raises ionized calcium more rapidly. 6, 5
• If only calcium gluconate is available, give 30 mL of 10% calcium gluconate (equivalent to 10 mL of 10% calcium chloride). 1

Vascular Access and Administration Route

Preferred Access

• Central venous access is strongly preferred to prevent extravasation injury, which can cause severe tissue necrosis, calcinosis cutis, and bullous skin reactions. 3, 6, 7
• If only peripheral access is available, calcium gluconate is safer than calcium chloride (which is highly caustic), but the line must be secure and closely monitored. 3, 6

Extravasation Risk

• Calcinosis cutis can occur with or without extravasation; if extravasation is suspected or bullous lesions appear, immediately stop the infusion and treat the site. 2, 7
• Tissue necrosis, ulceration, and secondary infection are the most serious complications of extravasation. 2

Continuous Infusion Protocol

Maintenance Infusion Rate

• After the initial bolus, start a continuous infusion at 50–100 mL/hour of the diluted solution (100 mL of 10% calcium gluconate in 1 liter of fluid). 1
• For calcium channel blocker toxicity, the infusion rate is 0.6–1.2 mL/kg/hour of 10% calcium gluconate. 4, 3
• For post-parathyroidectomy patients, initiate at 1–2 mg elemental calcium per kg per hour and titrate to maintain ionized calcium in the normal range (1.15–1.36 mmol/L). 3

Monitoring During Infusion

• Measure ionized calcium every 1–4 hours during continuous infusion and every 4–6 hours during intermittent boluses. 3, 2
• Avoid severe hypercalcemia (ionized calcium greater than twice the upper limit of normal). 6
• Continuous ECG monitoring is mandatory to detect bradycardia, arrhythmias, or QT changes. 3, 6, 2

Critical Safety Precautions

Cardiac Monitoring and Rate Control

• Stop the infusion immediately if heart rate decreases by 10 beats per minute or symptomatic bradycardia occurs. 3, 6
• Even "slow push" administration (over 5–10 minutes) carries arrhythmia risk and requires careful rate control. 3

Digoxin Interaction

• Avoid calcium administration in patients on digoxin whenever possible; if absolutely necessary, give slowly in small amounts with close ECG monitoring to prevent life-threatening arrhythmias. 3, 2
• Calcium and cardiac glycosides together can cause synergistic arrhythmias. 2

Hyperphosphatemia Caution

• When serum phosphate is elevated, exercise extreme caution: additional calcium increases the risk of calcium-phosphate precipitation in tissues, causing obstructive uropathy. 3
• Consider renal consultation before aggressive calcium replacement in this setting. 3

Special Populations

Renal Impairment

• Initiate at the lower limit of the dosage range and monitor serum calcium levels every 4 hours. 2

Elderly Patients

• Start at the low end of the dosage range due to increased risk of adverse effects. 2

Neonates

• Calcium gluconate is contraindicated in neonates (≤28 days) receiving ceftriaxone due to risk of fatal intravascular precipitates. 2

Common Pitfalls to Avoid

• Do not treat asymptomatic hypocalcemia—even in tumor lysis syndrome, no calcium replacement is indicated. 3
• Do not administer calcium rapidly without dilution—this causes hypotension, bradycardia, and cardiac arrest. 2
• Do not use peripheral access for calcium chloride—it is too caustic and will cause severe tissue injury. 6, 1
• Do not mix calcium with bicarbonate or phosphate solutions—immediate precipitation occurs. 3, 2