Reviewed by: HU Medical Review Board | Last reviewed: September 2022

Epinephrine is a man-made form of adrenaline. Adrenaline is a hormone made naturally by the body. Epinephrine is used to help manage severe allergic reactions. Allergic reactions may be triggered by insect bites, foods, drugs, or latex. Epinephrine may be used in adults and children.1-12

Epinephrine is used when an allergic reaction is severe, such as when a person has trouble breathing, vomiting, or their blood pressure drops. It is also used when an allergic reaction is progressing, such as when multiple symptoms develop. A severe allergic reaction is called anaphylaxis, and it is life-threatening. Epinephrine helps:3-5

  • Relax the muscles in the airways to help you breathe better
  • Reduce swelling of the mouth or throat
  • Increase your heart rate and squeeze your blood vessels to return blood pressure to normal

Epinephrine comes in several brand-name (EpiPen®, Adrenaclick®, Auvi-Q®, Symjepi®) and generic forms. It is mainly used as an auto-injection for anaphylaxis but also comes in nasal spray and liquid.6,7,9

What is the active ingredient in epinephrine?

Epinephrine is the active ingredient in these drugs.

How does epinephrine work?

Epinephrine works by reversing the symptoms of anaphylaxis. It causes blood vessels to narrow and heart rate to increase so that blood pressure increases. It also causes the airway muscles to relax, which makes it easier to breathe.1-10

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Epinephrine is most effective when injected quickly after a severe allergic reaction begins. It can help reduce throat swelling, difficulty breathing, and low blood pressure. Delays in giving someone epinephrine may lead to more severe reactions and even death.1-10

When to use epinephrine

Epinephrine is prescribed to treat people at high risk of anaphylaxis. If you have a known allergy and it triggers a serious reaction, your doctor may prescribe epinephrine. Serious symptoms of anaphylaxis include:1-3,6,8,9,12

  • Trouble breathing
  • Difficulty swallowing
  • Tightness in the throat
  • Repeated coughing
  • A weak pulse, dizziness, or fainting
  • Sudden hives, rash, or swelling of the skin
  • Vomiting, diarrhea, or abdominal pain

Talk to your doctor if you have any questions about how or when to use epinephrine. If you do use epinephrine, call 9-1-1. Tell them that epinephrine has been used. In some cases, more than 1 dose of epinephrine is needed to treat a severe reaction.1,6,7

What are the possible side effects of epinephrine?

The most common side effects of epinephrine include:6

  • Pounding or fast heartbeat
  • Skin redness, swelling, warmth, or tenderness at injection site
  • Headache, irritability, or agitation
  • Difficulty breathing
  • Nausea, vomiting
  • Sweating, dizziness, pale skin, or weakness

Side effects tend to last a short time, usually 2 to 3 minutes.6

These are not all the possible side effects of epinephrine. Talk to your doctor about what to expect when taking epinephrine. You also should call your doctor if you have any changes that concern you when taking epinephrine.

Things to know about epinephrine

In most cases, an auto-injector is used to give someone epinephrine. The auto-injector combines the drug and a needle in 1 device that is easy to carry at all times. Each injector holds 1 dose. The dose is different depending on how much someone weighs. Your prescribed dose may need to change over time.1,2,6

Epinephrine is typically sold in a pack with 2 pens. You should always carry both with you at all times.

The auto-injector is injected into the thigh during a severe allergic reaction. Someone on your healthcare team will show you how to use it. It is important to talk with your loved ones, teachers, and coworkers about how and when to use the epinephrine in case you are not able to inject it yourself.

Before using epinephrine, discuss all of your health conditions with your doctor. This is especially important if you have:6

  • An allergy to epinephrine or sulfites
  • Latex allergies
  • Cataracts, glaucoma, or an eye infection
  • High blood pressure, chest pain, irregular heartbeat, or heart disease
  • Diabetes
  • Overactive thyroid
  • An adrenal gland tumor
  • Depression or other mental illness
  • Parkinson's disease

Tell your doctor if you are pregnant or plan to become pregnant while using epinephrine.6

Epinephrine should be stored at room temperature away from heat, light, and moisture. Keep your autoinjector in its plastic carrying case and away from children. If you drop it, check to see if it is cracked or leaking. Check your epinephrine pen for an expiration date. Properly dispose of damaged or expired epinephrine pens to your local pharmacy.

Epinephrine may interact with other drugs, including:1,2,6

  • Certain antidepressants
  • Antihistamines
  • Beta blockers
  • Diuretics
  • Drugs for irregular heartbeats

Tell your doctor about all your health conditions and any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.

For more information, read the full prescribing information of epinephrine.