What is the dose and rate of calcium gluconate administration for a 70 kg patient with severe hyperkalemia?

Calcium Gluconate Dosing for Severe Hyperkalemia in a 70 kg Patient

For a 70 kg patient with severe hyperkalemia, administer 1,500-3,000 mg (15-30 mL) of 10% calcium gluconate intravenously over 2-5 minutes, not exceeding an infusion rate of 200 mg/minute. 1, 2, 3

Specific Dosing Parameters

Dose Calculation

• Standard adult dose: 15-30 mL of 10% calcium gluconate solution (equivalent to 1,500-3,000 mg calcium gluconate or 140-280 mg elemental calcium) 1, 2, 3
• For this 70 kg patient, use the full recommended range of 15-30 mL 1
• Each mL contains 100 mg calcium gluconate, providing 9.3 mg (0.465 mEq) of elemental calcium 3

Administration Rate

• Maximum infusion rate: 200 mg/minute in adults (DO NOT EXCEED) 3
• Recommended duration: Administer over 2-5 minutes 1, 2, 3
• This translates to approximately 3-6 minutes for the full 15-30 mL dose 1

Preparation and Administration

Dilution Requirements

• Dilute in 5% dextrose or normal saline to achieve a concentration of 10-50 mg/mL for bolus administration 3
• No specific dilution is required for the 10% calcium gluconate solution itself, as it can be given directly 1
• For a 30 mL dose, you could dilute in 50-100 mL of compatible fluid 3

Route and Access

• Administer via a secure intravenous line to avoid calcinosis cutis and tissue necrosis 3
• Preferably use a central venous catheter when available, though peripheral access is acceptable for calcium gluconate (unlike calcium chloride which mandates central access) 1, 2

Critical Monitoring During Administration

ECG Monitoring

• Continuous ECG monitoring is mandatory during calcium administration 1, 3
• Stop injection immediately if symptomatic bradycardia occurs 1, 2
• Look for resolution of hyperkalemia-related ECG changes (peaked T waves, widened QRS, prolonged PR interval) 2, 4

Expected Response

• Onset of action: 1-3 minutes after administration begins 2
• Duration of effect: 30-60 minutes (temporary) 2
• Calcium does NOT lower serum potassium—it only stabilizes cardiac membranes 1, 2

Complete Hyperkalemia Management Algorithm

Since calcium provides only temporary cardiac protection, you must simultaneously implement potassium-lowering strategies:

Step 1: Cardiac Membrane Stabilization (IMMEDIATE)

• Calcium gluconate 15-30 mL IV over 2-5 minutes 1, 2
• May need to repeat if ECG changes persist after 5-10 minutes 2

Step 2: Shift Potassium Intracellularly (15-30 minute onset)

• Insulin + glucose: 10 units regular insulin IV with 25g glucose (50 mL 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 if concurrent metabolic acidosis) 1, 2

Step 3: Remove Potassium from Body (longer-term)

• Loop diuretics: Furosemide 40-80 mg IV (only if adequate renal function) 1, 2
• Potassium binders: Patiromer or sodium zirconium cyclosilicate (newer, safer options) 2, 5
• Hemodialysis: Most effective for severe hyperkalemia, especially with renal failure 1, 2

Important Clinical Caveats

Calcium Chloride vs. Calcium Gluconate

• Calcium chloride (5-10 mL of 10%) provides more rapid increase in ionized calcium and may be preferred in cardiac arrest situations 1, 2
• However, calcium chloride requires central venous access due to severe tissue injury risk with extravasation 2
• For peripheral IV access, calcium gluconate is safer 1, 2

Common Pitfalls to Avoid

• Do NOT mix calcium gluconate with ceftriaxone—fatal precipitates can form 3
• Do NOT mix with bicarbonate or phosphate-containing solutions—precipitation will occur 3
• Avoid in digitalized patients without extreme caution—calcium can precipitate digitalis toxicity 3
• Remember that temporary measures (insulin/glucose, albuterol) last only 1-4 hours, and rebound hyperkalemia can occur 2

Monitoring Requirements

• Check serum potassium every 1-2 hours initially 2
• Monitor serum glucose closely after insulin administration 2
• Assess for overcorrection and hypokalemia 2

When Calcium May Be Most Effective

• Recent evidence suggests calcium treatment restores conduction through calcium-dependent propagation rather than true "membrane stabilization" 6
• Calcium is most effective when hyperkalemia produces conduction abnormalities (QRS widening, sine wave pattern) 7, 6
• Limited evidence shows calcium may be less effective for non-rhythm ECG changes 7