What to Know About GlucaGen (Glucagon)

A Drug Used to Raise Glucose Levels in an Emergency

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GlucaGen (glucagon) is an injectable prescription medication used to treat very low blood sugar, or hypoglycemia, in people with diabetes when other options are not available. It works by triggering the liver to release stored sugar, raising blood sugar levels.

Unlike sugar (glucose or dextrose), GlucaGen can be injected into the muscle directly, making it easy to use in an emergency. It may be given by trained caregivers at home, emergency responders, or healthcare providers.

Glucagon is also used for certain diagnostic imaging and off-label to treat overdoses of two classes of cardiac medications.

What to Know About GlucaGen

Verywell / Nusha Asjaee


Glucagon is part of a class of pharmaceuticals known as hormonal agents, which are natural or synthetic versions of hormones.

The U.S. Food and Drug Administration (FDA) has approved glucagon for two uses:

Severe Hypoglycemia

Low blood sugar is a potentially life-threatening medical emergency that is most commonly seen in patients with insulin-dependent diabetes mellitus. Patients with this condition control their blood sugar with a combination of injectable versions of insulin and diet. It is easy to accidentally force blood sugar too low, which results in emergency hypoglycemia.

Generally, severe hypoglycemia is defined as a glucose measurement of 70 milligrams per deciliter (mg/dL) or 3.9 millimoles per liter (mmol/L) or below. This is associated with confusion or coma.

The preferred treatment for hypoglycemia is to increase the patient's blood sugar through the ingestion of carbohydrates. In other words, eat sugar.

Because hypoglycemia causes confusion and, in some severe instances, a loss of consciousness, they may not be able to consume anything. In that case, only an injectable glucagon or nasal spray of glucagon can help.

Emergency healthcare providers (paramedics, emergency nurses, and emergency physicians) have intravenous dextrose available as an emergency medicine for treating hypoglycemic patients. But dextrose is not available for patients or family members to administer without medical training.

Previously, only orally-ingested glucose was available for patients and lay rescuers to administer without the aid of a healthcare provider. Oral glucose is simply a carbohydrate and almost any carbohydrate will do. Patients often respond well to things like frozen juice concentrate or other simple sugars as emergency treatments for mild hypoglycemia.

GlucaGen provides health professionals and others the ability to treat severe cases of hypoglycemia without a patient's active participation.

The American Diabetes Association (ADA) says that glucagon should be prescribed for all individuals at increased risk of level 2 or 3 hypoglycemia, so it is available should it be needed. Level 2 hypoglycemia is defined as blood glucose <54 mg/dL (3.0 mmol/L); level 3 hypoglycemia is defined as a severe event with altered mental and/or physical functioning that requires assistance.

Diagnostic Imaging

Glucagon is used in some imaging procedures along with MRI or CT scans to observe gastric function.

Glucagon relaxes the smooth muscle of the GI tract and temporarily halts gut motility to allow for clear images to be taken.

Off-Label Uses

High doses of glucagon are often used to treat overdoses of beta-blockers and calcium channel blockers—both heart medications. The effects of glucagon in this respect are well documented, if not completely understood.

Glucagon improves heart rate and blood pressure in patients that have taken too many beta-blockers or calcium channel blockers.

Glucagon is short-acting in these instances and may need to be administered as an infusion (intravenous drip) in order to sustain any substantial change in cardiac output.

Before Taking

Glucagon is available primarily as an emergency medication for use during severe episodes of hypoglycemia. A glucagon emergency kit and training to use it may be given to caregivers of patients at risk for severe hypoglycemia.

Precautions and Contraindications

There are some patients who should not receive GlucaGen due to their medical history. However, severe hypoglycemia is a serious situation that requires prompt treatment.

If a patient is unable to communicate with a rescuer and their medical history is unknown, glucagon may be administered as part of a standing protocol for treatment.

The following, if known, would prevent a patient from getting GlucaGen:

  • Adrenal gland tumor: Patients with a history of pheochromocytoma could have a severe high blood pressure (hypertensive) reaction to the administration of glucagon.
  • Tumors of the pancreas: Patients with a history of insulinoma or glucagonoma could have secondary hypoglycemia from the use of glucagon.
  • Known allergy: Patients may be allergic to glucagon and develop an anaphylactic reaction to the medication.

Glucagon is only effective in patients that have glycogen stores remaining in the liver and muscles. If the patient's glycogen stores have already been depleted, glucagon is ineffective.

Glucagon may not be useful if hypoglycemia is alcohol-induced since alcohol impairs the glycogen storage that is needed for glucagon to act.

Glucagon may cause a temporary increase in heart rate and blood pressure. It is due to this side effect that glucagon came to be used in cases of beta-blocker or calcium channel blocker overdose.

Other Hormonal Agents

Insulin is the most commonly used hormonal agent and is also a hormone that is naturally secreted by the pancreas for control of blood sugar. Generally, insulin acts in the opposite manner to glucagon and lowers blood sugar. Glucagon increases it.

Epinephrine, norepinephrine, and dopamine are other examples of hormonal agents. All are used in emergency settings to treat various metabolic and cardiac conditions.


Initial adult dosage for emergency hypoglycemia is 1 milligram (mg) administered intravenously (IV), intramuscularly (IM), or subcutaneously (SQ). There is also a new intranasal formulation, Baqsimi (glucagon), that is ready-to-use.

Initial doses can be repeated once if improvement is not noticed within 15 minutes. Further repeated doses for hypoglycemia in adults are likely to be ineffective and other emergency treatment, usually intravenous dextrose, should be attempted.

Children under 25 kilograms (kg)—about 55 pounds—may receive 0.5 mg IV, IM, or SQ for severe hypoglycemia. This dose may be repeated once.

How to Take and Store

Glucagon is supplied in 1-mg vials as a powder that has to be reconstituted with sterile water for injection. In emergency kit form, glucagon is supplied with a second vial containing the sterile water.

The sterile water is introduced into the vial containing the glucagon powder and the mixture is agitated (gently shaken) to create an injectable solution. The solution is then drawn up in a syringe for injection.

Any glucagon that has been reconstituted must be either administered immediately or discarded.

Once glucagon has been administered and the patient's level of consciousness increases, the patient should eat some form of complex carbohydrate to sustain blood sugar levels. Without eating, the effects of glucagon are temporary and the patient is likely to return to a state of hypoglycemia quickly.

Glucagon should be stored at room temperature and protected from direct sunlight.

Side Effects

Glucagon causes slowing of gut motility, which just means it slows or stops the churning that happens in the esophagus, stomach, and intestines. It's the reason glucagon is used for imaging of the GI tract, but it can lead to gastrointestinal upset.


Common side effects of glucagon include:

  • Nausea
  • Vomiting
  • Headache
  • Irritation or pain at the injection site
  • Lack of energy
  • Pale skin
  • Diarrhea
  • Drowsiness

Nausea is the most common adverse effect of glucagon and it does sometimes lead to vomiting.

For patients who receive glucagon as part of an imaging test, it could result in low blood sugar an hour or two after the dose is administered, when the effect of the glucagon has worn off. People are typically given juice or crackers after the test to prevent this from happening.


Rare side effects of glucagon include:

  • Necrolytic migratory erythema (NME): This rash can be caused by continuous infusions of glucagon over time. While typically associated with the aforementioned pancreatic cancer glucagonoma, the rash is not associated with cancer in this case.
  • Allergic reactions
  • Anxiety
  • Abdominal pain
  • Changes in heart rate or blood pressure, particularly causing a rapid heartbeat

Warnings and Interactions

The most clinically significant interaction between glucagon and another medication is with Indocin (indomethacin), which is used to treat some headache disorders.

Indomethacin can block the effects of glucagon on blood sugar, which would affect its usefulness in an emergency. Although rare and not well understood, glucagon could also increase bleeding in patients on blood thinners, particularly Coumadin (warfarin).

Talk to your healthcare provider if you are taking these drugs.

3 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
  1. U.S. Food and Drug Administration. Highlights of prescription information: GlucaGen.

  2. American Diabetes Association Professional Practice Committee. 6. Glycemic targets: Standards of medical care in diabetes—2022Diabetes Care. 2022;45(Supplement_1):S83-S96. doi:10.2337/dc22-S006

  3. Graudins A, Lee HM, Druda D. Calcium channel antagonist and beta-blocker overdose: Antidotes and adjunct therapiesBr J Clin Pharmacol. 2016;81(3):453–461. doi:10.1111/bcp.12763

Additional Reading

By Rod Brouhard, EMT-P
Rod Brouhard is an emergency medical technician paramedic (EMT-P), journalist, educator, and advocate for emergency medical service providers and patients.