Can taking 300 units of Humulin R (regular insulin) and 300 units of Basaglar (insulin glargine) be fatal?

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Last updated: February 1, 2026View editorial policy

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IMMEDIATE EMERGENCY - CALL 911 NOW

Taking 300 units of Humulin R (regular insulin) and 300 units of Basaglar (insulin glargine) together—a total of 600 units—is an extremely dangerous, potentially fatal overdose that requires immediate emergency medical intervention. This represents approximately 6-12 times the typical maximum daily insulin dose for most patients and will cause life-threatening severe hypoglycemia within hours 1, 2.

Why This Is Life-Threatening

Massive insulin overdoses cause profound, prolonged hypoglycemia that can result in:

  • Seizures, loss of consciousness, coma, and death from severe hypoglycemia (blood glucose <40 mg/dL) 3, 2
  • Brain damage from prolonged glucose deprivation to the central nervous system 3
  • Cardiovascular collapse from severe metabolic derangement 3

The combination of 300 units of rapid-acting regular insulin (Humulin R) plus 300 units of long-acting insulin glargine (Basaglar) creates a particularly dangerous situation because:

  • Humulin R will cause severe hypoglycemia within 30 minutes to 2 hours and continue acting for 6-8 hours 1
  • Basaglar will maintain dangerously low blood glucose for 24+ hours due to its prolonged duration of action 4, 5

Documented Case Evidence

A published case report describes a patient who injected 800 units of insulin lispro and 3,800 units of insulin glargine in a suicide attempt 2. This patient:

  • Required continuous 10% dextrose infusion at 200 mL/hour for 48 hours 2
  • Had plasma insulin levels of 3,712 uU/mL (normal range 2.6-31.1 uU/mL) 2
  • Required 109 hours of intensive care monitoring with frequent supplemental dextrose boluses 2
  • Needed daily plasma insulin level monitoring to guide treatment 2

This patient survived only because of immediate intensive medical intervention. Without emergency treatment, this overdose would have been fatal 2.

Required Emergency Treatment

If this overdose has occurred, the person needs:

  1. Immediate 911 call and emergency transport to a hospital emergency department 3, 2
  2. Continuous intravenous dextrose infusion (typically 10% dextrose at high rates) for 24-72+ hours 2
  3. Intensive care unit admission with hourly blood glucose monitoring 2
  4. Serial plasma insulin level measurements to guide duration of treatment 2
  5. Psychiatric evaluation if this was intentional self-harm 2

Critical Time Window

  • Hypoglycemia from Humulin R will begin within 30-60 minutes 1
  • Symptoms progress rapidly: confusion, sweating, tremors, seizures, loss of consciousness 3
  • Brain damage can occur within minutes once severe hypoglycemia develops 3
  • Treatment must begin BEFORE symptoms appear to prevent irreversible harm 2

Do NOT Attempt Home Treatment

Oral glucose, juice, or food will NOT be sufficient to counteract an overdose of this magnitude 2. The massive insulin load will continue driving glucose into cells faster than oral intake can compensate, and the prolonged action of 300 units of Basaglar will maintain hypoglycemia for days 4, 2, 5.

If this question is about an actual overdose situation: CALL 911 IMMEDIATELY. Every minute of delay increases the risk of permanent brain damage or death 3, 2.

References

Guideline

Initial Dosing for Lantus (Insulin Glargine) in Patients Requiring Insulin Therapy

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2026

Research

Massive insulin overdose managed by monitoring daily insulin levels.

American journal of therapeutics, 2011

Guideline

Concentration and Pharmacokinetics of Insulin Glargine Formulations

Praxis Medical Insights: Practical Summaries of Clinical Guidelines, 2025

Research

Insulin Glargine: a review 8 years after its introduction.

Expert opinion on pharmacotherapy, 2009

Professional Medical Disclaimer

This information is intended for healthcare professionals. Any medical decision-making should rely on clinical judgment and independently verified information. The content provided herein does not replace professional discretion and should be considered supplementary to established clinical guidelines. Healthcare providers should verify all information against primary literature and current practice standards before application in patient care. Dr.Oracle assumes no liability for clinical decisions based on this content.

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