Insulin is a hormone and medication used to help the body process glucose, or blood sugar, for energy. Like any powerful medication, the dosage must be precise. Taking an amount of insulin that exceeds the body’s immediate requirement for glucose transport can quickly become a serious medical event. When too much insulin is administered, the body’s glucose levels plummet, triggering immediate physiological consequences that demand swift action.
The Core Problem: Understanding Hypoglycemia
The immediate consequence of an insulin overdose is a sharp drop in blood glucose, known clinically as hypoglycemia. Insulin moves glucose from the bloodstream into the body’s cells to be used for fuel. When excessive insulin is present, this process accelerates, clearing glucose from circulation too rapidly.
For most individuals with diabetes, hypoglycemia is defined as a blood glucose level falling below 70 milligrams per deciliter (mg/dL). This rapid depletion starves the cells of their necessary energy source, which is particularly dangerous for the brain. Brain cells rely almost exclusively on glucose, and their function quickly becomes impaired when levels are too low, a state called neuroglycopenia.
Recognizing the Warning Signs
Symptoms of hypoglycemia typically begin quickly and are categorized into stages, reflecting the body’s escalating struggle to correct the low blood sugar. Mild symptoms often arise as the body releases stress hormones like adrenaline, which attempt to raise glucose levels. These early warning signs include:
- A feeling of shakiness or trembling.
- Excessive sweating.
- A rapid or pounding heartbeat.
- Intense hunger.
As blood sugar continues to drop, the brain begins to suffer from energy deprivation, leading to signs of moderate hypoglycemia. Individuals may experience dizziness, confusion, difficulty concentrating or speaking clearly, and pronounced mood changes, such as irritability or anxiety. When blood glucose falls below 54 mg/dL, it is considered Level 2 hypoglycemia, and the risk of severe impairment increases significantly.
Severe hypoglycemia, sometimes referred to as Level 3, is characterized by a person’s inability to function or treat themselves due to profound mental or physical changes. At this stage, the individual may lose consciousness, be unable to swallow, or experience a seizure. Without immediate assistance to administer treatment, this condition can lead to coma and, in rare instances, be life-threatening.
Immediate Emergency Response
Treating an insulin overdose requires immediate action based on the person’s current symptoms and ability to cooperate. If the person is conscious and able to safely swallow, the standard approach for mild to moderate hypoglycemia is the “Rule of 15.” This involves consuming 15 grams of a fast-acting carbohydrate, such as glucose tablets, four ounces of juice, or a tablespoon of sugar or honey.
After consuming the carbohydrate, the person must wait 15 minutes and then recheck their blood glucose level. If the reading is still below the target range, typically 70 mg/dL, the 15-gram carbohydrate treatment should be repeated. Once blood sugar is back in a safe range, the individual should consume a small snack or meal containing both carbohydrates and protein to prevent another drop.
For severe episodes, where the person is unconscious, seizing, or unable to swallow, emergency glucagon must be administered immediately. Glucagon is a hormone that instructs the liver to release its stored glucose into the bloodstream, rapidly raising blood sugar. It is available as an injection or a nasal spray, and the chosen method should be administered by a trained bystander. After administering glucagon, the person should be turned onto their side in case of vomiting, and emergency medical services should be called immediately.
Preventing Future Incidents
The most common causes of accidental insulin overdose stem from dosing errors or a mismatch between the insulin dose and carbohydrate intake or activity level. Simple mistakes like misreading numbers on a syringe or pen, or accidentally injecting rapid-acting insulin instead of long-acting insulin, can lead to a significant excess dose. Another frequent cause is taking the correct dose but then skipping or delaying a scheduled meal or snack.
Prevention involves establishing strict routines and double-checking every step of the dosing process. Always confirm the type of insulin and the number of units before injection, especially when using multiple types. It is essential to carry fast-acting carbohydrate sources at all times and to wear a medical ID to alert others to a hypoglycemic emergency. Regular communication with a healthcare team about physical activity and meal changes is necessary to ensure insulin dosages are appropriately adjusted to the body’s changing needs.