What is the recommended dose of calcium gluconate for treating hyperkalemia?

Calcium Gluconate Dosing for Hyperkalemia

The recommended dose of calcium gluconate for treating hyperkalemia is 10 mL of 10% solution (1 gram) administered intravenously over 2-5 minutes, with the option to repeat if no effect is observed within 5-10 minutes. 1

Mechanism and Timing of Action

Calcium gluconate works by stabilizing cardiac cell membranes, reducing the risk of cardiac arrhythmias associated with hyperkalemia. It acts rapidly, within 1-3 minutes of administration, but does not significantly reduce serum potassium levels 1. This makes it a critical first-line intervention for cardiac protection while other potassium-lowering therapies take effect.

Dosing Protocol

Adults:

• Initial dose: 10 mL of 10% calcium gluconate (1 gram) IV over 2-5 minutes
• Repeat dosing: May repeat after 5-10 minutes if ECG changes persist 1
• Alternative: If in cardiac arrest, calcium chloride 10% (10 mL) is preferred due to faster onset 1, 2

Children:

• Dose: 60 mg/kg of calcium gluconate IV 1
• For severe cases: 50-100 mg/kg may be infused and cautiously repeated if necessary 1

Administration Considerations

1. Route: Administer through a central venous catheter when possible
2. Caution: Extravasation through peripheral IV can cause severe skin and soft tissue injury 1
3. Monitoring: Perform ECG monitoring during administration
4. Infusion rate: Give by slow push for cardiac arrest; infuse over 30-60 minutes for other indications 1

Clinical Decision Making

The decision to administer calcium gluconate should be based on:

1. Severity of hyperkalemia (particularly if >6.5 mmol/L)
2. Presence of ECG changes (peaked T waves, prolonged PR interval, widened QRS)
3. Symptoms of hyperkalemia (muscle weakness, paresthesia)

Complete Hyperkalemia Management Algorithm

1. Stabilize cardiac membrane (immediate action):

   • Calcium gluconate 10%: 10 mL IV over 2-5 minutes 1

2. Shift potassium into cells (within 15-30 minutes):

   • Insulin: 10 units regular insulin IV with 50 mL of 50% dextrose 1, 3
   • Albuterol: 10-20 mg nebulized over 15 minutes 1
   • Sodium bicarbonate: 50 mEq IV over 5 minutes (particularly if metabolic acidosis present) 1

3. Remove potassium from body (longer-term):

   • Diuretics: Furosemide 40-80 mg IV 1
   • Potassium binders: Patiromer or sodium zirconium cyclosilicate 1
   • Dialysis: For severe cases or when other measures fail 1

Important Caveats

• ECG findings can be variable and may not always correlate with potassium levels 1
• Calcium gluconate appears most effective for rhythm disorders due to hyperkalemia but less effective for non-rhythm ECG disorders 4
• The effect of calcium gluconate is temporary (1-3 hours), so definitive treatment to lower potassium levels must be initiated concurrently 1, 3
• Continuous infusion of combination therapy (calcium gluconate, insulin, dextrose) may be considered for ongoing management in certain settings 5

Remember that hyperkalemia is a medical emergency that requires prompt recognition and treatment to prevent potentially fatal cardiac arrhythmias. The calcium gluconate dose should be administered immediately when severe hyperkalemia is identified, particularly when ECG changes are present.