What is the management approach for a patient who has taken an intentional insulin overdose, considering toxodynamics?

Management of Intentional Insulin Overdose

Immediate Emergency Actions

Stop all insulin administration immediately and begin aggressive IV dextrose therapy with continuous glucose monitoring every 15 minutes initially. 1, 2

First-Line Treatment Protocol

• Administer 10-20 grams of hypertonic (50%) dextrose IV as an immediate bolus, titrating based on hypoglycemia severity 1
• Initiate continuous IV glucose infusion immediately after the bolus 1
• Recheck blood glucose in 15 minutes and repeat dextrose bolus if glucose remains low 1
• Do not delay treatment to obtain initial glucose measurement if testing is unavailable 1

Critical Monitoring Requirements

• Monitor blood glucose every 15 minutes initially, then hourly once stabilized 1
• Continue monitoring for at least 59 hours after long-acting insulin (glargine) overdose, as the duration of action significantly exceeds the usual time-effect profile 3
• Monitor serum potassium, magnesium, and phosphate levels closely, as hypokalemia, hypomagnesemia, and hypophosphatemia commonly develop 2, 4, 5
• Check liver enzymes, as elevations are common with insulin overdose 4

Advanced Treatment Options

Glucagon Administration

• Consider glucagon 1 mg IM or IV for acute rescue in the pre-hospital or initial emergency setting 6, 7
• For refractory hypoglycemia requiring excessive dextrose, administer continuous IV glucagon infusion: 3-10 mg IV bolus over 3-5 minutes, followed by 3-5 mg/hour infusion 1
• Critical limitation: Glucagon depletes hepatic glycogen stores and becomes ineffective with repeated dosing 6
• Manage nausea with antiemetics, as glucagon commonly causes vomiting 1
• Protect the airway before administration if the patient has altered mental status 1

Octreotide for Refractory Cases

• Consider octreotide (somatostatin analogue) in non-diabetic patients experiencing rebound hypoglycemia from endogenous insulin release triggered by exogenous dextrose administration 8
• Octreotide may help prevent dextrose-induced hypoglycemia and stabilize blood glucose when large dextrose infusion volumes cause complications like peripheral edema 8
• Initiate octreotide if recurrent hypoglycemic episodes persist despite aggressive dextrose therapy (typically after 12+ hours) 8

Electrolyte Management

• Do not aggressively replace potassium above 2.5-2.8 mEq/L, as this can precipitate fatal arrhythmias 6
• Correct hypokalemia appropriately but cautiously 2
• Monitor and replace magnesium and phosphate as needed 5

Vascular Access Considerations

• Concentrated dextrose solutions >10% require central venous access to prevent peripheral vein damage 6, 1
• Consider early central line placement if prolonged high-concentration dextrose infusions are anticipated 1

Neurological Protection

• Maintain glucose >70 mg/dL (>100 mg/dL if neurologic injury is present) to prevent neurocognitive damage 1
• Permanent hypoglycemic encephalopathy is possible with severe or prolonged glycopenia 1
• The main danger of insulin overdose is hypoglycemia and its effects on the central nervous system 5

Oral Carbohydrate Support

• When the patient responds to treatment and is able to swallow, provide oral carbohydrates to restore liver glycogen and prevent recurrence of hypoglycemia 2, 7
• Liberal oral intake should be encouraged when possible, in addition to IV dextrose 5
• Sustained carbohydrate intake and observation are necessary because hypoglycemia may recur after apparent clinical recovery 2

Diagnostic Confirmation

• Measure insulin and C-peptide levels to distinguish exogenous insulin administration from endogenous secretion 4
• The insulin-to-C-peptide ratio helps confirm intentional insulin overdose 4
• Suspect insulin overdose in diabetic patients with unexplained prolonged hypoglycemia and in non-diabetic patients with hypoglycemia who may have access to diabetic medications 4

Duration of Monitoring and Treatment

• For long-acting insulin (glargine) overdose: Glucose infusions may be required for up to 59 hours or longer, significantly exceeding the usual time-effect profile 3
• For rapid-acting insulin (aspart, lispro) overdose: Hypoglycemia typically resolves within 24-40 hours 5, 9
• Do not prematurely discontinue glucose infusion, as this risks relapse of severe hypoglycemic episodes 3
• Even massive oral insulin ingestion (3000 units) can cause symptomatic hypoglycemia requiring 24 hours of monitoring, despite poor oral bioavailability (~1%) 9

Common Pitfalls to Avoid

• Never underestimate the duration of action of long-acting insulin analogues after massive overdose—continue monitoring and treatment for at least 59 hours 3
• Never target aggressive potassium repletion >2.8 mEq/L in the acute phase to avoid asystole 6
• Never discontinue glucose infusion prematurely based on apparent clinical recovery, as hypoglycemia may recur 2, 3
• Never delay treatment to obtain confirmatory testing if insulin overdose is suspected 1

Psychiatric Evaluation

• Psychiatric evaluation is of paramount importance for early identification of depression and suicidality 4
• Insulin overdose occurs not only among people with diabetes but also among their relatives and medical/paramedical personnel with access to insulin 4
• Transfer to a mental health facility is appropriate once medical stabilization is achieved 5