What is the preferred calcium salt, calcium gluconate or calcium chloride (CaCl2), for treating hyperkalemia?

Calcium Chloride vs Calcium Gluconate in Treatment of Hyperkalemia

Calcium chloride is preferred over calcium gluconate for treating hyperkalemia, especially in critically ill patients, due to its more rapid increase in ionized calcium concentration. 1

Comparison of Calcium Salts

• Calcium chloride (10%): 5-10 mL (500-1000 mg) IV over 2-5 minutes is recommended by the American Heart Association as first-line treatment for cardiac membrane stabilization in hyperkalemia 1, 2
• Calcium gluconate (10%): 15-30 mL IV over 2-5 minutes can be substituted if calcium chloride is not available 1, 2
• Calcium chloride provides a more rapid increase in ionized calcium concentration than calcium gluconate, making it more effective in critically ill patients 1
• The effects of calcium administration begin within 1-3 minutes but are temporary, lasting only 30-60 minutes 1, 2

Dosing Considerations

• For pediatric patients: calcium chloride dosing is 20 mg/kg (0.2 mL/kg for 10% CaCl₂) 1
• For adults: calcium chloride 10% at 5-10 mL (500-1000 mg) IV over 2-5 minutes 1, 2
• Calcium dose equivalence: 10 mL of 10% calcium gluconate contains 2.2 mmol of calcium, while 4.4 mL of 7.35% calcium chloride contains 5 mmol of calcium 3
• This difference in calcium content explains why calcium chloride is more effective at the same volume 3

Administration Considerations

• Calcium chloride administration should be through a central venous catheter when possible, as extravasation through a peripheral IV line may cause severe skin and soft tissue injury 1
• Calcium gluconate has less risk of tissue damage if extravasated, making it safer for peripheral administration 2
• Monitor heart rate during calcium administration and stop injection if symptomatic bradycardia occurs 1
• If no effect is observed within 5-10 minutes of calcium administration, another dose may be given 1

Clinical Efficacy

• Calcium administration does not lower serum potassium but protects against cardiac arrhythmias by stabilizing cardiac membranes 1, 2
• Calcium is particularly important for treating ECG changes associated with hyperkalemia, including peaked T waves, flattened P waves, prolonged PR interval, and widened QRS 1, 2
• A study of hyperkalemic patients found that calcium gluconate was effective, albeit to a limited degree, in treating main rhythm ECG disorders due to hyperkalemia 4
• The FDA notes that while calcium chloride is used to combat the deleterious effects of hyperkalemia as measured by ECG, adequate well-controlled randomized clinical studies have not been done to fully support this indication 5

Complete Hyperkalemia Management Algorithm

1. Cardiac membrane stabilization (immediate effect):

   • Calcium chloride (10%): 5-10 mL IV over 2-5 minutes (preferred) 1, 2
   • OR Calcium gluconate (10%): 15-30 mL IV over 2-5 minutes if calcium chloride unavailable 1, 2

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

   • Insulin with glucose: 10 units regular insulin IV with 25g glucose (50 mL of D50W) over 15-30 minutes 1, 2
   • Nebulized albuterol: 10-20 mg over 15 minutes 1, 2
   • Sodium bicarbonate: 50 mEq IV over 5 minutes (especially effective in patients with concurrent metabolic acidosis) 1, 2

3. Eliminate potassium from body (longer-term effect):

   • Loop diuretics: furosemide 40-80 mg IV (effective only in patients with adequate renal function) 1, 2
   • Cation exchange resins or newer potassium binders 1, 2
   • Hemodialysis for severe or refractory cases 1, 2, 6

Important Clinical Considerations

• Temporary measures such as insulin/glucose and albuterol provide only transient effects (1-4 hours), and rebound hyperkalemia can occur after 2 hours 2
• The combination of nebulized beta-agonists with IV insulin-and-glucose may be more effective than either alone 7
• Monitoring potassium levels closely during treatment is crucial to avoid overcorrection and hypokalemia 2
• Review and adjust medications that may contribute to hyperkalemia, such as ACE inhibitors, ARBs, and NSAIDs 2