Symptoms and Signs of Insulin Reaction

Medical Author: John P. Cunha, DO, FACOEP
Medically Reviewed on 9/10/2021

Doctor's Notes on Insulin Reaction

An insulin reaction occurs when a person with diabetes becomes confused or unconscious due to low blood sugar (hypoglycemia) caused by insulin or oral diabetic medications. In people with diabetes, the pancreas is unable to produce enough insulin to meet the body's demand and treatment may include oral hypoglycemics, insulin, or both. A common cause of an insulin reaction (or hypoglycemia) is a missed meal. Other causes for insulin reaction include exercise and medication error.

Mild symptoms of insulin reaction include

Moderate symptoms of insulin reaction include

  • confusion,
  • headache, and
  • poor coordination.

Severe symptoms of insulin reaction include

  • unconsciousness,
  • seizures,
  • coma,
  • stroke-like symptoms, and
  • hypothermia (low body temperature) if the hypoglycemia persists for a prolonged period of time.

What Is the Treatment for Insulin Reaction?

Most people with diabetes or their families can recognize the early symptoms of an insulin reaction due to low blood sugar and it may be self-treated if it is not severe. Immediately drink something with sugar (juices, regular soda, or sugar water). Glucose tablets can also provide instant sugar into the bloodstream.

If symptoms of an insulin reaction are severe and the diabetic person is unconscious or has difficulty staying awake, do not put food or drink into an unconscious person's mouth because there is a risk it will go into the lungs and cause pneumonia. If a person is not responsive enough to take fluids or food, call 9-1-1 right away. If the patient has a glucagon pen (injectable glucagon device), administer it.

Emergency personnel may start an intravenous line (IV) and inject a highly concentrated glucose solution. If the patient takes long-acting insulin or oral hypoglycemic medication, the IV line may be left in place and dextrose (a type of sugar) solution may be continually infused.

Most patients successfully treated for low blood sugar from an insulin reaction are able to be discharged home after a short observation period. Some patients who wake up quickly and have the ability to monitor their glucose levels and have someone that can watch over them may not need to be transferred to the hospital.

Some cases of low blood glucose from an insulin reaction happen because of other complicating medical issues. Elderly, chronically ill, or fragile patients may need to be admitted to the hospital for further evaluation and treatment.

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Kasper, D.L., et al., eds. Harrison's Principles of Internal Medicine, 19th Ed. United States: McGraw-Hill Education, 2015.