Glucose-Insulin-Potassium (GIK) Infusion Regimen
For beta-blocker or calcium channel blocker overdose with refractory shock, administer 1 U/kg regular insulin as an IV bolus with 0.5 g/kg dextrose, followed by continuous infusions of 0.5-1 U/kg/hour insulin and 0.5 g/kg/hour dextrose, titrating to hemodynamic response while maintaining serum glucose 100-250 mg/dL. 1
Clinical Context and Indications
The term "GIK infusion" has different meanings depending on clinical context. The most robust evidence-based regimen is for toxicological emergencies, specifically beta-blocker overdose with shock refractory to standard vasopressor therapy. 1
Beta-Blocker/Calcium Channel Blocker Overdose Protocol
Initial Bolus:
Continuous Infusion:
- Insulin: 0.5-1 U/kg/hour, titrated to achieve adequate hemodynamic response (appropriate mean arterial pressure and evidence of good perfusion) 1
- Dextrose: 0.5 g/kg/hour, titrated to maintain serum glucose 100-250 mg/dL (5.5-14 mmol/L) 1
Critical Monitoring Requirements:
- Serum glucose monitoring up to every 15 minutes during initial dextrose titration phase 1
- Sustained infusions of concentrated dextrose solutions (>10%) require central venous access 1
- Target serum potassium levels of 2.5-2.8 mEq/L to avoid overly aggressive repletion, as animals treated with aggressive potassium repletion developed asystole 1
Mechanism: High-dose IV insulin improves myocardial energy utilization and hemodynamic stability in beta-blocker overdose. Animal studies and human case reports demonstrate improved survival in refractory shock from massive metoprolol overdose. 1
Alternative GIK Formulations (Historical/Limited Evidence)
Acute Myocardial Infarction (Not Currently Recommended)
Historical GIK protocols for acute MI consisted of:
- 500 mL of 10% glucose containing 16 U human soluble insulin and 20 mmol potassium chloride 2
- Infusion rate: 100 mL/hour 2
- Alternative formulation: 300 g glucose, 50 units regular insulin, and 80 mEq potassium chloride per liter, infused at 0.013-0.032 mL/kg/min 3
Important caveat: Recent large trials showed no mortality benefit from GIK in acute MI, and high-dose GIK induced hyperglycemia (70.8% vs 33.8% in controls) which was associated with increased one-year mortality. 4 This approach is not recommended for routine use in acute MI.
Acute Stroke (Investigational Only)
The GIST trial used 16 U human soluble insulin and 20 mmol potassium chloride in 500 mL 10% glucose at 100 mL/hour for 24 hours in hyperglycemic stroke patients. 2 However, this produced only attenuated glucose control and effectiveness remains unproven. 2
Standard ICU Insulin Infusion (Not GIK)
For general hyperglycemia management in critically ill patients, standard insulin infusion without the glucose-potassium component is preferred:
- Prepare as 1 unit/mL continuous infusion 1
- Prime new tubing with 20 mL waste volume 1
- Target glucose 140-180 mg/dL for most critically ill patients 1
- Use validated written or computerized protocols for dose adjustments 1
This is distinct from GIK and represents modern intensive insulin therapy without fixed glucose/potassium co-administration. 1
Key Clinical Pitfalls
- Hypoglycemia risk: Very frequent glucose monitoring (every 15 minutes initially) is essential during high-dose insulin-dextrose therapy 1
- Potassium management: Moderate hypokalemia is common during high-dose insulin therapy; target 2.5-2.8 mEq/L rather than aggressive normalization 1
- Hyperglycemia from GIK: Traditional GIK formulations for cardiac conditions can induce significant hyperglycemia, which is independently associated with worse outcomes 4
- Central access requirement: Concentrated dextrose solutions (>10%) mandate central venous access 1
- Context matters: The term "GIK" encompasses different regimens for different conditions; the toxicological high-dose insulin protocol differs fundamentally from historical cardiac GIK formulations 1, 4, 2