Do I give regular insulin for hyperkalemia?

Yes, Give Regular Insulin for Hyperkalemia

Regular insulin is a cornerstone therapy for acute hyperkalemia, administered intravenously to shift potassium intracellularly with onset of action within 15-30 minutes and effects lasting 4-6 hours. 1

When to Administer Insulin

Give insulin for:

• Moderate hyperkalemia (6.0-6.4 mEq/L) with or without ECG changes 1
• Severe hyperkalemia (≥6.5 mEq/L) regardless of symptoms 1
• Any hyperkalemia with ECG changes (peaked T waves, widened QRS, prolonged PR interval, flattened P waves) regardless of the absolute potassium value 1

Do NOT give insulin if:

• Potassium <3.3 mEq/L – this is an absolute contraindication as insulin will drive potassium even lower and cause life-threatening arrhythmias 2
• Mild hyperkalemia (5.0-5.5 mEq/L) without ECG changes or symptoms – insulin is not indicated for mild asymptomatic hyperkalemia 1

Dosing Protocol

Standard Dose (Most Common)

10 units of regular insulin IV is the standard dose, administered either as:

• IV bolus over 2-5 minutes, OR 1
• Continuous infusion at 0.1 units/kg/hour 1

Always administer with 25-50 grams of dextrose to prevent hypoglycemia 1, 3

Reduced Dose (For High-Risk Patients)

5 units of regular insulin IV (or 0.1 units/kg) should be considered for patients at higher risk of hypoglycemia: 4

• Low baseline glucose 4
• No history of diabetes mellitus 4
• Female sex 4
• Altered renal function (low eGFR) 4, 5
• Lower body weight 4

Administer with 50 grams of dextrose when using reduced dose insulin 4

Higher Dose (For Severe Cases)

20 units of regular insulin as continuous IV infusion over 60 minutes may be used as an alternative in: 3

• Severe hyperkalemia (K+ >6.5 mEq/L) 3
• Marked ECG changes (prolonged PR interval, wide QRS complex) 3

Administer with 60 grams of dextrose when using 20 units 3

Critical Considerations

Glucose Administration

• Never give insulin without glucose – hypoglycemia can be life-threatening 1
• Dextrose can be given as a rapid IV bolus or prolonged infusion to reduce hypoglycemia risk 4
• 50 grams of dextrose is superior to 25 grams for preventing hypoglycemia 4

Monitoring Requirements

• Check blood glucose hourly for at least 4-6 hours after insulin administration, as insulin's duration of action may exceed that of dextrose 1, 4
• Check potassium levels every 2-4 hours after initial administration 1
• Continuous cardiac monitoring is mandatory during treatment 1

Efficacy Comparison

No statistically significant difference exists between 10 units bolus, 10 units infusion, or 20 units infusion in mean potassium decrease at 60 minutes (0.78-0.79 mmol/L reduction) 3. However, conventional 10-unit dosing may be more effective than 5-unit dosing when baseline potassium >6 mEq/L (difference: -0.238 mmol/L, P=0.018) 6

Hypoglycemia Risk

• Approximately 20% of patients experience hypoglycemia with insulin treatment for hyperkalemia 3
• Severe hypoglycemia (glucose <50 mg/dL) occurs in 7-9% of patients 5
• Reduced dose protocols (5 units) decrease hypoglycemia incidence from 28% to 11% without increasing severe hypoglycemia 7
• No difference in hypoglycemia rates between 5 and 10 units in patients with low eGFR (16.7% vs 19.7%, P=0.79), but monitoring remains critical 5

Common Pitfalls to Avoid

• Do not rely on insulin alone – it only temporizes by shifting potassium intracellularly and does NOT remove potassium from the body 1
• Do not delay calcium administration if ECG changes are present – give calcium first for cardiac membrane stabilization (onset 1-3 minutes), then insulin 1
• Do not stop monitoring glucose after 4 hours – hypoglycemia can occur up to 6-8 hours after insulin administration, especially with higher doses 5
• Do not use insulin as monotherapy – simultaneously initiate potassium removal strategies (loop diuretics, potassium binders, or hemodialysis) 1
• Do not forget to repeat insulin dosing – effects last only 4-6 hours, so insulin can be repeated every 4-6 hours as needed while carefully monitoring glucose and potassium 1

Algorithm for Insulin Use in Hyperkalemia

1. Verify potassium ≥3.3 mEq/L – if <3.3 mEq/L, hold insulin and aggressively replete potassium first 2
2. Obtain ECG immediately – if ECG changes present, give calcium gluconate first 1
3. Assess patient risk factors for hypoglycemia (low glucose, no diabetes, female, renal dysfunction, low weight) 4
4. Choose insulin dose:
   • High-risk patients: 5 units IV + 50g dextrose 4
   • Standard patients: 10 units IV + 25-50g dextrose 1
   • Severe hyperkalemia with marked ECG changes: 20 units IV infusion over 60 min + 60g dextrose 3
5. Monitor glucose hourly for 4-6 hours and potassium every 2-4 hours 1, 4
6. Initiate definitive potassium removal (diuretics, binders, or dialysis) simultaneously 1