An insulin overdose can occur if a person with diabetes takes too much of the medication. This can lead to symptoms of hypoglycemia, such as sweating, confusion, and a rapid heartbeat.

The correct insulin dosage differs for each individual and can depend on factors such as the time of day you take the medication and if you’re insulin-resistant. Taking an excess amount can result in an insulin overdose.

An insulin overdose is a medical emergency and requires immediate medical treatment.

According to the Centers for Disease Control and Prevention (CDC), 12% of adults with diabetes take insulin. When taken as prescribed, insulin can be lifesaving.

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Excess insulin in the bloodstream can cause cells in your body to absorb too much glucose (sugar) from your blood. It also causes the liver to release less glucose. Together, these two effects create dangerously low glucose levels in your blood. This condition is called hypoglycemia.

Your blood needs the right amount of glucose for your body to function properly. Glucose is the body’s fuel. Without it, your body is like a car running out of gas. The severity of insulin overdose can depend on how low your blood sugar level has dropped.

Mild hypoglycemia

Symptoms of low blood sugar may include:

These signs indicate a mild or moderate case of hypoglycemia. However, they still require immediate medical attention so they don’t lead to dangerously low blood sugar.

The CDC recommends that those with low blood sugar levels eat 15 grams of fast-digesting carbohydrates, such as glucose tablets or high glucose food. Foods high in glucose include:

  • grapes
  • soda
  • fruit juice
  • honey
  • sweetcorn

Your symptoms should improve within 15 minutes of eating. If they don’t, or if a test shows your levels are still low, it can be helpful to repeat the steps above until your blood sugar level is above 70 mg/dL. If your symptoms still don’t improve after three treatments, you should seek medical help immediately.

Severe hypoglycemia

A healthcare professional will typically diagnose you as having severe hypoglycemia if your reading is below 54 mg/dL.

Severe symptoms of hypoglycemia, sometimes referred to as diabetic shock or insulin shock, include:

If a person becomes unconscious due to too much insulin, you should call 911 immediately. It can be helpful for anyone taking insulin to have glucagon available, as it can counteract the effects of insulin. This typically needs to be injected by family members or emergency personnel.

Keep in mind that even if you use glucagon to treat hypoglycemia, you should still go to the emergency room.

Like all medications, it’s important to take insulin in the right amounts. The correct dosage will be beneficial without harm.

Basal insulin is the insulin that keeps your blood sugar steady all day. The correct dosage depends on many things, such as the time of day and if you’re insulin-resistant. For mealtime insulin, the proper dosage depends on factors such as:

  • your fasting or premeal blood sugar level
  • the carbohydrate content of the meal
  • any activity planned after your meal
  • your insulin sensitivity
  • your target postmeal blood sugar goals

There are several different types of insulin medications. Some are fast-acting and will work within about 15 minutes. Short-acting (regular) insulin begins to work within 30–60 minutes. These are the types of insulin you need to take before meals.

Other types of insulin are more lasting and are used for basal insulin. They take longer to affect blood sugar levels but provide protection for 24 hours.

The strength of insulin may also vary. The most common strength is U-100, or 100 units of insulin per milliliter of fluid. People who are more insulin-resistant may require more than this, so the drug is available at up to U-500 strength.

All these factors come into play in determining the right dosage for you. It’s important to keep in mind that while doctors provide basic guidance, accidents can happen.

Accidentally overdosing on insulin is not as rare as it may seem. You might overdose accidentally if you:

  • forget a previous injection and take another before it’s necessary
  • are distracted and accidentally inject too much
  • are unfamiliar with a new product and use it incorrectly
  • forget to eat or have an unexpected mealtime delay
  • exercise vigorously without changing the insulin dose as needed
  • take someone else’s dose by mistake
  • take a morning dose at night, or vice versa

Realizing you’ve overdosed can be a scary situation. It can be beneficial to understand the symptoms of insulin overdose to ensure you know when to seek medical support and can receive the treatment you need as soon as possible.

In a 2022 review, researchers acknowledged that people with diabetes are at an increased risk of depression and suicide. Sometimes, a person who is experiencing depression or another mental health condition may take an insulin overdose on purpose.

If you or a loved one is experiencing depression, consider speaking with a healthcare professional. It can also be helpful to ensure that you’re aware of the emergency signs and symptoms of insulin overdose. It may help save someone’s life.

Help is out there

If you or someone you know is in crisis and considering suicide or self-harm, please seek support:

While you wait for help to arrive, stay with someone and remove any weapons or substances that can cause harm. You are not alone.

If you’re calling on behalf of someone else, stay with them until help arrives.

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What happens if you take too much insulin?

Taking too much insulin can increase your risk of developing hypoglycemia.

This is a condition where your blood sugar drops below a healthy range. If your levels drop too low, it can lead to severe hypoglycemia symptoms, also known as diabetic shock. Severe symptoms can include seizures and unconsciousness.

What should you do if you accidentally take the wrong insulin?

If you accidentally take the wrong type of insulin, there are several steps you can take to avoid hypoglycemia.

This includes monitoring your blood sugar levels closely and consuming more carbohydrates to help increase your blood sugar levels. If this does not help and your symptoms worsen, you should seek immediate medical support.

How long does an insulin overdose last?

The side effects of an insulin overdose typically last for an average of 3 days. However, this can vary for each individual.

If your symptoms are severe, the effects may last for a longer period. In this case, you should seek emergency medical support, which will allow a doctor to monitor your symptoms and discharge you when it’s safe.

Can an insulin overdose cause a heart attack?

An insulin overdose cannot directly cause a heart attack. However, taking too much insulin can result in hypoglycemia, which can increase the risk of a heart attack. The likelihood of this is significantly higher for those with prior heart conditions.

Whether it’s accidental or intentional, insulin overdose can be a life threatening situation. Some instances of high insulin and low blood sugar can be fixed by eating something high in glucose.

However, severe symptoms that do not respond to treatment should be treated as an emergency.

If you’re with someone who is showing severe symptoms of insulin overdose, take action right away. Call 911 and administer glucagon if you have it available.