Skip to main content

EpiPen Auto-Injector

Generic name: epinephrine injectionEP-i-NEF-rin ]
Brand names: EpiPen 2-Pak, EpiPen JR 2-Pak
Drug classes: Adrenergic bronchodilators, Catecholamines, Vasopressors

Medically reviewed by Melisa Puckey, BPharm. Last updated on Oct 24, 2023.

What is EpiPen?

EpiPen and Epipen Jr are used to treat life-threatening allergic reactions (anaphylaxis) to insect stings or bites, foods, drugs, and other allergens, and also treat exercise-induced anaphylaxis. EpiPen Auto-Injectors reduce wheezing and improve low blood pressure, hives, severe low blood pressure, and other symptoms of an allergic reaction.

EpiPen contains epinephrine from a class of medications called sympathomimetic agents which works by relaxing the muscles in the airways and tightening the blood vessels. Epinephrine is also called adrenaline.

EpiPen Auto-Injectors are hand-held devices that automatically inject a measured dose of medicine. EpiPen Auto-Injectors make it easier to give epinephrine in an emergency when anaphylaxis occurs. Anaphylaxis can be life-threatening and can happen within minutes and, if untreated, can lead to death. Each EpiPen or EpiPen Jr auto-injector can be used only 1 time (single-use). 

Patients with a history of severe allergic reactions should keep EpiPen or EpiPen Jr Auto-injectors on hand for immediate self-injection if they have an allergic reaction. Epipens are for emergency supportive therapy only and do not take the place of emergency medical care. You should get emergency help right away after using your EpiPen or EpiPen Jr auto-injector.

EpiPen and EpiPen Jr auto-injectors have a Never-See-Needle® that covers the needle before and after you inject, so you should never see a needle. If you can see a needle, do not use the EpiPen or EpiPen Jr auto-injector.

What is anaphylaxis?

Anaphylaxis is a life-threatening allergic reaction to insect stings or bites, foods, drugs, exercise-induced anaphylaxis, and other allergens. Sometimes the cause of anaphylaxis is unknown. EpiPen and Epi-pen Jr Auto-Injectors reduce wheezing and improve low blood pressure, hives, severe low blood pressure, and other symptoms of an allergic reaction. Anaphylaxis can happen within minutes and, left untreated, can lead to death

Symptoms of anaphylaxis may include:

Anaphylaxis is treated with epinephrine injections such as Epipen, but you must seek emergency medical treatment right away, even if you have used the EpiPen or EpiPen Jr auto-injector.


EpiPen Auto-Injectors are used to treat severe allergic reactions (anaphylaxis).

Seek emergency medical attention even after you use EpiPen to treat a severe allergic reaction. You will need to receive further treatment and observation.

Before using EpiPen a second time, tell your doctor if your first injection caused a serious side effect such as increased breathing difficulty, or dangerously high blood pressure (severe headache, blurred vision, buzzing in your ears, anxiety, confusion, chest pain, shortness of breath, uneven heartbeats, seizure).

It is recommended that patients at risk of anaphylaxis carry 2 auto-injectors in case the first auto-injector is activated before the dose can be given, or you need a second dose.

You may not know when anaphylaxis will happen. Talk to your healthcare provider if you need more auto-injectors to keep at work, school, or other locations. Make sure your family members, caregivers, and others where you keep your EpiPen or EpiPen Jr auto-injectors and they know how to use it before you need it. You may be unable to speak in an allergic emergency. 

A “trainer pen” is available to teach and practice giving an injection. The trainer pen contains no medicine and no needle. 

How should I use EpiPen?

Read and carefully follow any Instructions for Use provided with your medicine. Ask your doctor or pharmacist if you do not understand these instructions.

The EpiPen Auto-Injector device is a disposable single-use system. An Auto-Injector can only be used one time. You may need to use a second EpiPen auto-injector if symptoms continue or come back while you wait for emergency help or if the first auto-injector is activated before the dose can be given.

Do not remove the safety cap until you are ready to use the Auto-Injector. Never put your fingers over the injector tip after the safety cap has been removed.

Do not give this medicine to a child without medical advice.

EpiPen is injected into the skin or muscle of your outer thigh. In an emergency, this injection can be given through your clothing. Do not inject into a vein or into the buttocks, fingers, toes, hands or feet.

To use an EpiPen Auto-Injector:

If you accidentally inject yourself while giving EpiPen to another person you must seek medical attention.

Accidental injection into fingers, hands or feet may cause a loss of blood flow to these areas. If an accidental injection happens, go immediately to the nearest emergency room.

Use an Auto-Injector only once, then throw away in a puncture-proof container (ask your pharmacist where you can get one and how to dispose of it). Keep this container out of the reach of children and pets.

Do not try to reuse the same Auto-Injector a second time. If the needle is bent from the first use, it may cause serious injury to your skin.

Do not use the EpiPen if it has changed colors or has any particles in it, or if the expiration date on the label has passed. Call your doctor for a new prescription.

Your medicine may also come with a "trainer pen." The trainer pen contains no medicine and no needle. It is only for non-emergency use to practice giving yourself an injection.

Dosing information

Usual Epipen dose patients over 30kg (66 lbs): EpiPen 0.3 mg. 

Usual Epipen dose patients 15 to 30 kg (33 lbs to 66 lbs): EpiPen Jr 0.15 mg.

Inject intramuscularly or subcutaneously into the outer thigh, through clothing if necessary. Each device is a single-dose injection.

Epipen is available as:

EpiPen Auto-Injector 0.3 mg (0.3 mg/0.3 mL) single-dose pre-filled auto-injector

EpiPen Jr Auto-Injector: 0.15 mg (0.15 mg/0.3 mL) single-dose pre-filled auto-injectorkilograms).

Before using this medicine

Before using EpiPen, tell your doctor if any past use has caused an allergic reaction to get worse.

To make sure this medicine is safe for you, tell your doctor if you have ever had:

Pregnancy and breastfeeding

Having an allergic reaction while pregnant or nursing could harm both mother and baby. 

You may need to use EpiPen during pregnancy or while you are breastfeeding. Seek emergency medical attention right away after using the injection. Epinephrine is the first-line medication of choice for the treatment of anaphylaxis during pregnancy and breastfeeding. Epinephrine should be used for the treatment of anaphylaxis during pregnancy and breastfeeding in the same manner as it is used in non-pregnant and non-breastfeeding patients.

If possible during an emergency, tell your medical caregivers if you are pregnant or breastfeeding.

What happens if I miss a dose?

Since EpiPen is used when needed, it does not have a daily dosing schedule.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Overdose symptoms may include numbness or weakness, severe headache, blurred vision, pounding in your neck or ears, sweating, chills, chest pain, fast or slow heartbeats, severe shortness of breath, or cough with foamy mucus.

What should I avoid while using EpiPen?

Do not inject EpiPen into a vein or into the muscles of your buttocks, or it may not work as well. Inject it only into the fleshy outer portion of the thigh.

EpiPen side effects

Before using EpiPen, tell your doctor if any past use has caused an allergic reaction to get worse.

Call your doctor at once if you notice pain, swelling, warmth, redness, or other signs of infection around the area where you gave an injection.

Side effects may be more likely in older adults.

Common EpiPen side effects may include:

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

What other drugs will affect EpiPen?

Tell your doctor about all your other medicines, especially:

This list is not complete. Other drugs may interact with epinephrine, including prescription and over-the-counter medicines, vitamins, and herbal products. Not all possible drug interactions are listed here.



Active Ingredients: epinephrine

Inactive Ingredients: sodium chloride, sodium metabisulfite, hydrochloric acid, and water


Manufactured for: Mylan Specialty L.P., Morgantown, WV 26505, U.S.A. by Meridian Medical Technologies, LLC, St. Louis, MO 63146, U.S.A.

Popular FAQ

If someone is having an anaphylactic reaction, and all you have on hand is a recently expired EpiPen, then use it so long as it is not discolored and does not contain any particles. There is minimal risk in using a recently expired EpiPen, but the benefits are significant. But check the clear viewing window of the pen and if you notice it is discolored or contains particles then don’t use it as the solution may have oxidized, making it less effective. Continue reading

You can bring your EpiPen onto a plane – they are a common medical device and they should not cause any fuss when you are going through airport security. You can carry them in your handbag, laptop bag, or other carry-on luggage. It is a very good idea to take your EpiPen with you on the plane because the small confines of an aircraft increase your odds of being exposed to a trigger allergen while you are flying and having an anaphylactic reaction. Continue reading

Epinephrine works by activating both alpha and beta receptors found in your body in response to a severe allergy (called anaphylaxis). By acting on alpha receptors, it helps to maintain your blood pressure and heart function, and by acting on beta receptors, it relaxes your lung airways to help relieve shortness of breath and wheezing. Continue reading

Epipen (epinephrine injection) is given as an intramuscular (in the muscle) or subcutaneous (under the skin) injection only in the middle of the outer side of the thigh (the upper leg). It can be injected through clothing if needed. Continue reading

EpiPen and Symjepi are both for intramuscular or subcutaneous use to treat allergic emergencies (anaphylaxis). Unlike EpiPen, Symjepi does not come as an "autoinjector" but comes only as a prefilled syringe. Symjepi has smaller size and may be more user-friendly than other products. Continue reading

More FAQ

View more FAQ

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.