Case Presentation: 57-year-old male with type II Diabetes on insulin therapy and depression, with prior suicidal attempts on opioids presented to the Emergency Department (ED) after an intentional injection of 320 Units of glargine. His home medications were glargine 20 U daily and metformin 500 mg twice a day. On arrival to the ED, he was alert and oriented with a finger stick blood glucose level of 87 mg/dL. Laboratory values showed a random plasma glucose level of 61 mg/dL and potassium level of 3.4 mEq/L. He was admitted to the Intensive Care unit for frequent monitoring of blood glucose and electrolytes and liberal oral feeding was encouraged. After approximately 10 hours, his blood glucose dropped to 49 mg/dL requiring multiple 50% dextrose boluses. A 10% dextrose drip was then started at 100 cc/hour. Despite continuous dextrose infusion, he continued to experience intermittent episodes of hypoglycemia requiring additional dextrose boluses. Glucagon injection was also administered. His blood glucose levels stabilized after 72 hours and the dextrose drip was stopped. He was then transferred to the psychiatric unit where he was treated for depression with behavioral therapy and antidepressants. He was discharged on the tenth day of hospitalization.
Discussion: Insulin glargine is a recombinant human insulin analog which has been shown to have a smooth 24-hour action profile with no undesirable peaks of activity. However, a minority of patients experience a premature decline in activity that typically occurs between 18 and 24 hours requiring more frequent dosing. The clinical effect of administration of large doses of insulin is variable, with reports of prolonged hypoglycemia for as long as 92 hours; the cause of which is unclear. We describe a case of glargine overdose requiring prolonged monitoring of blood glucose and electrolytes and aggressive dextrose supplementation.
Conclusions: Although initial blood glucose levels can be normal, patients with glargine overdose can experience prolonged hypoglycemia requiring vigilant monitoring and dextrose support for an extended period of time. It is unclear why administration of large doses of glargine causes prolonged hypoglycemia even though pharmacokinetic studies have not shown a prolonged long half-life. Though not used in our case, incision and drainage of injection site and octreotide have been tried as a treatment option in resistant cases. Physicians should be aware of prolonged hypoglycemia after glargine overdoses to avoid early termination of care and to avoid life threatening hypoglycemic episodes.