epinephrine injection, autoinjector

  • Pharmacy Author:
    Omudhome Ogbru, PharmD

    Dr. Ogbru received his Doctorate in Pharmacy from the University of the Pacific School of Pharmacy in 1995. He completed a Pharmacy Practice Residency at the University of Arizona/University Medical Center in 1996. He was a Professor of Pharmacy Practice and a Regional Clerkship Coordinator for the University of the Pacific School of Pharmacy from 1996-99.

  • Medical and Pharmacy Editor: John P. Cunha, DO, FACOEP
    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, FACOEP

    John P. Cunha, DO, is a U.S. board-certified Emergency Medicine Physician. Dr. Cunha's educational background includes a BS in Biology from Rutgers, the State University of New Jersey, and a DO from the Kansas City University of Medicine and Biosciences in Kansas City, MO. He completed residency training in Emergency Medicine at Newark Beth Israel Medical Center in Newark, New Jersey.

What is epinephrine auto-injector, and how does it work (mechanism of action)?


  • EpiPen is an auto-injectable epinephrine-containing device used for self-administration during life-threatening allergic reactions, including anaphylaxis. Epinephrine, the medicine contained in EpiPen, is an excitatory chemical naturally made by our bodies. Epinephrine stimulates alpha and beta-adrenergic receptors found throughout the body. When injected during an allergic reaction, epinephrine works in multiple ways to treat the many signs of anaphylaxis. It causes blood vessels to constrict or tighten which helps to increase blood pressure and decrease swelling. Epinephrine also stimulates the heart muscle, causing the heart to beat faster and pump more blood to the vital organs. Epinephrine helps patients breathe better by relaxing the muscles in the lungs and allowing the airways to open up. Additionally, it also helps to prevent further release of inflammatory chemicals that were triggered by the initial allergic reaction.
  • The FDA approved EpiPen in December 1987.

What brand names are available for epinephrine auto-injector?

EpiPen, EpiPen Jr

Is epinephrine auto-injector available as a generic drug?


Do I need a prescription for epinephrine auto-injector?


What are the uses for epinephrine auto-injector?

Epinephrine autoinjectors are used for emergency treatment of allergic reactions, including

  • anaphylactic reactions caused by inset stings or bites,
  • allergen immunotherapy,
  • foods,
  • drugs,
  • chemicals used for diagnostic testing substances such as radiocontrast media, and
  • other allergens.

EpiPen also is used for treating anaphylaxis due to exercise or unknown causes.

EpiPen is used for emergency use only and are should not replace proper medical care.

What are the side effects of epinephrine auto-injector?

Common side effects of EpiPen include:

Possible serious side effects of EpiPen include:

What is the dosage for epinephrine auto-injector?

  • The recommended dose is the contents of 1 autoinjector (0.3 mg or 0.15 mg) injected under the skin or into the muscle of the thigh.
  • The dose may be repeated after 5-15 minutes if symptoms persist.
  • Patients that weigh 30 kg or more (approximately 66 pounds or more) should receive 0.3 mg (EpiPen) and patients that weigh 15 to 30 kg (33 pounds to 66 pounds) should receive 0.15 mg (EpiPen Jr).
  • EpiPen may be injected through clothing if necessary.

Which drugs or supplements interact with epinephrine auto-injector?

  • Administration of epinephrine to patients taking cardiac glycosides, diuretics (water pills), or drugs for treating irregular heartbeats (anti-arrhythmics) can cause the development of irregular heartbeats.
  • The effects of epinephrine may be enhanced by medicines such as tricyclic antidepressants, monoamine oxidase inhibitors (MAOIs), levothyroxine (Synthroid, Levoxyl), and certain antihistamines.
  • The treatment benefits of epinephrine can be reduced by beta-adrenergic blocking medicines such as propranolol (Inderal) and alpha-adrenergic blocking medicines such as phentolamine (Regitine, OraVerse).
  • Some anti-migraine medications may also interfere with the benefits of epinephrine treatment.

Is epinephrine auto-injector safe to take if I'm pregnant or breastfeeding?

  • Use of epinephrine has not been adequately evaluated in pregnant women. Use of epinephrine in animal studies was associated with birth defects. Epinephrine should be used during pregnancy only if the potential benefit justifies the potential risk to the fetus.
  • It is not known if epinephrine is excreted in breast milk. Since many drugs are excreted in human milk and have the potential of causing harm to the nursing infant, caution should be used when epinephrine is administered to a nursing mother.

What else should I know about epinephrine auto-injector?

What preparations of epinephrine auto-injector are available?

Autoinjector: 0.15 mg/0.3 ml, 0.3 mg/0.3 ml

How should I keep epinephrine auto-injector stored?

  • EpiPen should be stored at room temperature, between 15 C and 30 C (59 F and 86 F).
  • It shouldn't be refrigerated.
  • Epinephrine is light sensitive and should be stored in the carrier tube provided to protect it from light.


EpiPen and EpiPen Jr (epinephrine injection, autoinjector) is a prescription drug used for the emergency treatment of allergic reactions. Side effects of EpiPen include:

Drug interactions, dosage, and pregnancy and breastfeeding safety information should be reviewed prior to using this drug.

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REFERENCE: FDA Prescribing Information