What is the maximum dose of calcium gluconate in hyperkalemia?

Maximum Dose of Calcium Gluconate in Hyperkalemia

For adults with hyperkalemia and ECG changes, administer 10% calcium gluconate 15-30 mL (1,500-3,000 mg) IV over 2-5 minutes as the initial dose, and if no ECG improvement occurs within 5-10 minutes, a second identical dose may be given. 1

Initial Dosing and Administration

• The American College of Cardiology recommends 10% calcium gluconate at 15-30 mL IV over 2-5 minutes for cardiac membrane stabilization in adults with hyperkalemia 1
• The FDA-approved maximum infusion rate is 200 mg/minute in adults, which translates to administering 3,000 mg (30 mL of 10% solution) over 15 minutes at the absolute fastest rate 2
• For bolus administration, dilute calcium gluconate to a concentration of 10-50 mg/mL in 5% dextrose or normal saline prior to administration 2

Repeat Dosing Protocol

• If no ECG improvement is observed within 5-10 minutes after the initial dose, a second dose of calcium gluconate may be administered 1
• The Mayo Clinic recommends monitoring the ECG response for 5-10 minutes after the initial dose before considering repeat administration 1
• The onset of action is rapid, occurring within 1-3 minutes of administration 1, 3
• The effects are temporary, lasting only 30-60 minutes, so concurrent therapies to shift potassium intracellularly and promote elimination must be initiated simultaneously 1, 3

Pediatric Dosing Considerations

• For pediatric patients with hyperkalemia, the recommended dose is 100-200 mg/kg/dose via slow infusion with ECG monitoring 1
• The maximum infusion rate in pediatric patients, including neonates, is 100 mg/minute 2
• The American Heart Association recommends pediatric dosing of 20 mg/kg (0.2 mL/kg) of 10% calcium chloride over 5-10 minutes, with calcium gluconate preferred for peripheral access 3

Critical Monitoring Requirements

• Monitor heart rate during calcium administration and stop injection if symptomatic bradycardia occurs 1
• Continuous ECG monitoring is mandatory during and after administration 3
• Administer via a secure intravenous line to avoid calcinosis cutis and tissue necrosis 2

Important Clinical Caveats

• Calcium administration does not lower serum potassium but protects against cardiac arrhythmias by stabilizing cardiac membranes 1
• Calcium should not be administered through the same line as sodium bicarbonate to avoid precipitation 1
• In patients with high phosphate levels, increased calcium might increase the risk of calcium phosphate precipitation in tissues 1
• Calcium gluconate is preferred over calcium chloride when administering through a peripheral IV line, as calcium chloride can cause severe tissue injury if extravasation occurs 1

Special Population: Malignant Hyperthermia

• In patients with malignant hyperthermia and hyperkalemia, calcium should only be used in extremis as it may contribute to calcium overload of the myoplasm 3

Practical Algorithm for Calcium Administration

1. Verify hyperkalemia with ECG changes present 1, 3
2. Administer 15-30 mL of 10% calcium gluconate IV over 2-5 minutes 1
3. Monitor ECG continuously during administration 3, 2
4. Assess ECG response at 5-10 minutes 1
5. If no improvement, administer second dose of 15-30 mL 1
6. Simultaneously initiate insulin/glucose, beta-agonists, and arrange for definitive potassium removal 1, 3