Should we administer emergency glucagon (glucagon) injection to an adult diabetic patient who received a large dose of short-acting insulin (e.g. Humalog (insulin lispro)) and is at risk for severe hypoglycemia?

Emergency Glucagon Administration for Insulin Overdose

Yes, administer emergency glucagon immediately for an adult diabetic patient who received a large dose of short-acting insulin and is at risk for severe hypoglycemia. 1, 2

Immediate Action Required

Glucagon should be administered as soon as severe hypoglycemia is recognized, without waiting for blood glucose confirmation if the patient is unconscious or unable to swallow. 1, 3

When to Administer Glucagon

• Severe hypoglycemia (Level 3): Patient has altered mental status or physical function requiring external assistance for recovery 4, 1
• Blood glucose <54 mg/dL (3.0 mmol/L) with inability to take oral carbohydrates 4, 2
• Unconscious or unable to swallow: This is an absolute indication for glucagon rather than oral glucose 4, 2

Dosing and Administration

For Adults (>25 kg or ≥6 years)

• Administer 1 mg (1 mL) glucagon via intramuscular (IM), subcutaneous (SC), or intranasal route 1, 3
• Preferred formulations: Ready-to-inject or intranasal glucagon are superior to traditional reconstitution kits due to faster administration (27 seconds vs 97 seconds) and ease of use 1, 5
• Injection sites: Upper arm, thigh, or buttocks 3

Expected Response Timeline

• Blood glucose should increase within 5-15 minutes after glucagon administration 1
• Mean time to glucose >70 mg/dL: Approximately 10-14 minutes from injection 5, 6
• Recovery of consciousness: Typically 4-7 minutes, though slower than IV dextrose 6

Critical Post-Administration Steps

Immediate Follow-Up (Within 15 Minutes)

• Call emergency services immediately after administering glucagon 3
• Monitor blood glucose to ensure adequate response 1
• If no response after 15 minutes: Administer a second 1 mg dose using a new kit while awaiting emergency assistance 3

Once Patient Responds

• Give oral carbohydrates immediately when the patient can swallow safely to restore liver glycogen and prevent recurrent hypoglycemia 1, 2, 3
• Provide a full meal or snack containing complex carbohydrates and protein 2

Important Clinical Considerations

Why Glucagon Works in This Scenario

• Short-acting insulin (Humalog) overdose creates a situation where hepatic glycogen stores are intact but glucose production is suppressed 3
• Glucagon mobilizes hepatic glycogen to raise blood glucose, making it effective for insulin-induced hypoglycemia 3

Common Pitfalls to Avoid

• Do NOT delay administration waiting for blood glucose confirmation if severe hypoglycemia is suspected clinically 1, 2
• Protect the airway first: Nausea and vomiting are common side effects (particularly with higher doses), so position the patient to prevent aspiration 1
• Do NOT give insulin - family members must be explicitly educated never to administer insulin during a hypoglycemic episode 1

Limitations of Glucagon

• Glucagon will NOT work if: The patient has depleted hepatic glycogen stores (prolonged fasting, chronic alcohol use, adrenal insufficiency) 3
• IV dextrose is superior when available: In hospital settings with IV access, dextrose 20-40 mL of 50% solution provides faster response than glucagon 1, 2, 6

Prevention of Recurrence

Insulin Regimen Adjustment Required

• This episode mandates immediate insulin regimen modification 2
• Reduce subsequent insulin doses by 20-50% until the cause of overdose is identified and corrected 2
• Investigate the cause: Dosing error, missed meal, unexpected exercise, or impaired renal function 4, 2

Ongoing Monitoring

• Hypoglycemia can recur because short-acting insulin (Humalog) has a duration of action of 3-5 hours, which may outlast the effect of a single glucagon dose 2
• Continue blood glucose monitoring every 15-30 minutes for at least 3-4 hours after the initial event 2
• Provide continuous carbohydrate intake during this monitoring period 2