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Patient information: Use of an epinephrine autoinjector (Beyond the Basics)

INTRODUCTION

Allergic reactions can be triggered by foods, medications, exercise, latex, insect stings, or unknown triggers, and can cause a sudden, potentially life-threatening allergic reaction called anaphylaxis. Epinephrine (also known as adrenaline) is a medicine that treats the symptoms of serious allergic reactions. (See "Patient information: Anaphylaxis symptoms and diagnosis (Beyond the Basics)".)

PATIENT AND FAMILY EDUCATION

A person with allergies, as well as his or her family, close friends, teachers, and co-workers, should learn to use an epinephrine autoinjector before it is needed. Anaphylaxis is unpredictable, and while a person may have a mild reaction one time, a serious or even life-threatening reaction can occur the next time. A person suffering with anaphylaxis may panic and be unable to assist with their own injection. In addition, a quick response is necessary to prevent serious complications of anaphylaxis.

An epinephrine autoinjector prescription should be filled immediately. Anyone who is at risk of anaphylaxis should keep at least one epinephrine autoinjector with them at all times. Most allergy specialists recommend having at least two doses of epinephrine available, and some prescribe more. The reason for this is that two doses of epinephrine may be needed to treat a more severe anaphylactic reaction.

After filling the prescription, patients/caregivers should practice using the autoinjector. Many manufacturers include a practice injector (that does not have a needle or actual medicine). A video (on the internet or DVD) showing how the autoinjector is used is available from some manufacturers and should be reviewed periodically.

The autoinjector should always be available, including at school or work, when attending parties or traveling, during exercise, and while dining out. It should be kept in a place that can be easily located by others in an emergency and family and friends should be informed about where the injector is stored. It is also important to ensure that the injector is not expired, although an expired injector may be used if there is no alternative.

Epinephrine should be stored at normal room temperature, away from extreme cold and heat. The epinephrine cartridge window should be examined periodically to ensure that the solution is colorless and contains no floating particles. Solutions that are discolored or contain particles should be replaced. Autoinjectors that have expired should be replaced even if the solution still looks clear.

SYMPTOMS OF ALLERGY

Allergic reaction can produce symptoms throughout the body. The symptoms of anaphylaxis are discussed in detail in a separate topic. (See "Patient information: Anaphylaxis symptoms and diagnosis (Beyond the Basics)".)

EPINEPHRINE IS THE BEST TREATMENT FOR ANAPHYLAXIS

Epinephrine is the best treatment for anaphylaxis and it works best if it is given within the first few minutes of a severe allergic reaction. Epinephrine rapidly treats all of the most dangerous symptoms of anaphylaxis, including throat swelling, difficulty breathing, and low blood pressure. However, epinephrine is not a perfect treatment, so allergic triggers should be avoided.

Other medicines that are used in the treatment of allergic reactions can help with some of the symptoms, but only epinephrine treats the entire reaction. Antihistamines (such as diphenhydramine and others) help with itching and hives, and asthma inhalers (such as albuterol) can help with coughing and wheezing, but these medications do not treat the dangerous symptoms of throat swelling and low blood pressure. In addition, antihistamines taken by mouth are too slow-acting to be effective in a rapidly-developing episode of anaphylaxis. In contrast, injected epinephrine works within a few minutes.

In short, antihistamines and asthma inhalers are useful in the treatment of anaphylaxis, but they are NOT substitutes for epinephrine. There is no substitute for epinephrine in anaphylaxis.

WHEN TO USE AN EPINEPHRINE AUTOINJECTOR

A person who is having an allergic reaction should use their epinephrine autoinjector immediately if they:

  • Are having trouble breathing
  • Feel tightness in the throat
  • Feel lightheaded or think they might pass out

If treating a child with an allergic reaction, also use the autoinjector if the child:

  • Is not responding, seems groggy, or passes out during an allergic reaction.
  • Has food allergies and is vomiting repeatedly shortly after eating, especially if these symptoms are accompanied by flushing or hives.
  • Is coughing repeatedly during an allergic reaction.
  • Had previous anaphylaxis and develops widespread hives after possibly eating a trigger food.
  • Has definitely eaten a trigger food that previously caused very severe anaphylaxis. In this case, use the autoinjector before symptoms appear.

HOW TO USE AN EPINEPHRINE AUTOINJECTOR

The patient and a family member should review instructions provided with the autoinjector each time a refill is obtained in case there are changes. Instructions may differ from one autoinjector to another.

Epipen or Epipen Jr. — These epinephrine autoinjectors contain one dose per injector. They are available in two different doses, one intended for older children and adults, and the other for use in young children.

Stay with other people if possible. There is no need to undress, because the injector works through clothing. However, when possible, lift the edge of a skirt or lower pants to avoid hitting a buckle, zipper, or contents of the pockets.

 1.  Flip open the cap and remove the pen from its carrier tube.

 2.  Hold the injector in your dominant hand, making a fist. Keep fingers away from both ends to avoid sticking them. The end with the orange tip contains the needle and should be facing down. Use your other hand to pull off the blue safety release.

 3.  Hold the orange tip near the outer thigh. Swing and firmly push against the outer thigh until it clicks so that the unit is perpendicular (90 degree angle) to the thigh. Hold in place for 10 seconds to allow all the medicine to be injected (picture 1). The cartridge window will become obscured.

 4.  Remove the pen from the thigh. The orange needle cover will extend to automatically cover the needle.

5.  Massage the injected area for 10 seconds.

 6.  Call 911 and get to the nearest emergency department immediately (patients should not drive themselves). Allergic reactions sometimes come back.

 7.  Take the used autoinjector with you to the hospital emergency room so that it can be disposed of safely.

The Epipen is available in packages of two, in case a second dose is needed. Large-sized adults may need to repeat the dose. A second dose may also be needed if symptoms are not improving or getting worse after about five minutes, or if symptoms come back before reaching the emergency department.

Auvi-Q — These epinephrine autoinjectors contain one dose per injector. They are rectangular, about the size of a cellular phone, and play a recording that explains each step in the self-injecting process. They are available in two different doses, one intended for older children and adults, and the other for use in young children.

Stay with other people if possible. There is no need to undress, because the injector works through clothing. However, when possible, lift the edge of a skirt or lower pants to avoid hitting a buckle, zipper, or contents of the pockets.

1.  Pull downwards to remove the blue or red case.

 2.  Pull off the red safety guard. This will reveal a black end which contains a needle inside. Do not place your finger or hand over the black end.

 3.  Place the black end against the upper, outer thigh, and press down hard until the autoinjector fires (you will hear a click and a hiss). Hold in place for 5 seconds to allow all the medicine to be injected.

 4.  Remove the injector.

5.  Call 911 and get to the nearest emergency department immediately. (Patients should not drive themselves). Allergic reactions sometimes come back.

6.  Take the used injector to the hospital for disposal.

Other devices — Two other autoinjectors, Adrenaclick and Twinject, are currently unavailable in the United States, although they may be reintroduced at a later date.

Adrenaclick — This autoinjector contains one dose of epinephrine. It is available in two different strengths, one intended for use in children and the other, for use in adolescents and adults. Adrenaclick is not currently available in the United States, although it may be again in the future.

Stay with other people if possible. There is no need to undress, because the injector works through clothing. However, when possible, lift the edge of a skirt or lower pants to avoid hitting a buckle, zipper, or contents of the pockets.

 1.  Remove the injector from its gray case.

 2.  Pull off the gray cap, labeled "1". This will reveal a red tip, which contains a needle inside. Do not place your finger or hand over the red tip.

 3.  Pull off the gray cap, labeled "2".

 4.  Form a fist around the autoinjector with the red tip pointing down.

 5.  Place the red tip against the upper, outer thigh, and press down hard until the autoinjector fires (picture 1). Hold in place for 10 seconds to allow all the medicine to be injected.

 6.  Remove the injector and check the red cap. If the needle is visible, epinephrine was given. If the needle is not present, repeat steps 4 through 5 again.

 7.  Massage the injected area for 10 seconds.

 8.  Call 911 and get to the nearest emergency department immediately. (Patients should not drive themselves). Allergic reactions sometimes come back.

 9.  Place the used injector back into the carrying case needle end first, and close the case by putting the light gray case top over the non-needle end and close the case. Take the case to the hospital for disposal.

Twinject — This autoinjector contains two doses in one device. It is available in two different strengths, one intended for use in children and the other, for use in adolescents and adults. Twinject is not currently available in the United States, although it may be again in the future.

Stay with other people if possible. There is no need to undress, because the injector works through clothing. However, when possible, lift the edge of a skirt or lower pants to avoid hitting a buckle, zipper, or contents of the pockets.

 1.  Remove the injector from its case.

 2.  Pull off the green cap, labeled "1". This will reveal a red tip, which contains a needle inside. Do not place your finger or hand over the red tip.

 3.  Pull off the green cap, labeled "2".

 4.  Form a fist around the autoinjector with the red tip pointing down.

 5.  Place the red tip against the upper, outer thigh, and press down hard until the autoinjector fires (picture 1). Hold in place for 10 seconds to allow all the medicine to be injected.

 6.  Remove the injector and check the red cap. If the needle is visible, epinephrine was given. If the needle is not present, repeat steps 4 through 5 again.

 7.  Massage the injected area for 10 seconds.

 8.  Call 911 and get to the nearest emergency department immediately. (Patients should not drive themselves). Allergic reactions sometimes come back.

The Twinject contains a second dose inside the cartridge. A second dose may be needed if symptoms are not improving or getting worse after about five minutes, or if symptoms come back before reaching the emergency department. Studies have shown that one in three patients will need a second dose.

In case a second dose is needed, remove the inside injector:

  • Unscrew and remove the red rounded tip, taking care to avoid the needle.
  • Pull the blue syringe out of the barrel.
  • Slide the yellow collar off the plunger. Do not pull up on the plunger.

To use the second dose:

  • Press the injector firmly into your thigh muscle; push the plunger all the way down to inject the medicine.
  • Remove the injector.
  • Massage the injected area for 10 seconds.
  • Place the used syringe and needle back into the case and take it to the hospital.

If the second dose was not needed, the syringe/needle can be stored in the case for disposal at the hospital. The second dose CANNOT be saved for use another day.

Immediately after using the autoinjector — After using an autoinjector, it is important to immediately seek care in an emergency department. The reaction may initially improve, but then come back. When possible, ask someone else to call for help. If alone, treat with the autoinjector first and then call or walk for help.

If the person experiencing anaphylaxis begins to feel weak or dizzy, have them lie down and elevate the knees or feet. If they feel faint or have fainted, leave them in the lying down position. NEVER prop them up because this can prevent blood from reaching the heart and brain.

Side effects of epinephrine — The benefits of epinephrine are FAR GREATER than the risk of side effects. However, epinephrine can cause short-lived side effects in some patients. The most common side effects include the following:

  • Heart — Fast and/or pounding heartbeat, fleeting chest pain
  • Nervous system — Nervousness, trembling, feeling cold, anxiety, headache, dizziness
  • Digestive system — Nausea, dry throat
  • Lungs — Fleeting shortness of breath

Injector disposal — The injector should not be thrown away in the normal trash. Instead, patients should take their used or expired injector (inside the case) to a hospital or healthcare provider for proper disposal.

FOLLOW-UP CARE

People have varying responses to a severe allergic reaction. Some people have symptoms that will resolve rapidly and completely with treatment. These people may feel tired, but otherwise normal afterwards. Other people have symptoms that take longer to resolve. For most people, facial swelling and asthma symptoms resolve completely after 24 to 48 hours.

Some people experience a second reaction after the initial allergic reaction, although this is not common. Second reactions can occur hours to days later, although most second reactions happen within eight hours. For this reason, it is important to stay at the emergency department for several hours of observation after a reaction.

A healthcare provider may prescribe additional medications for treatment after a reaction, such as antihistamines or oral glucocorticoids (eg, prednisone). It is possible (but not proven) that these medications can help to prevent a second reaction.

WHERE TO GET MORE INFORMATION

Your healthcare provider is the best source of information for questions and concerns related to your medical problem.

This article will be updated as needed on our web site (www.uptodate.com/patients). Related topics for patients, as well as selected articles written for healthcare professionals, are also available. Some of the most relevant are listed below.

Patient level information — UpToDate offers two types of patient education materials.

The Basics — The Basics patient education pieces answer the four or five key questions a patient might have about a given condition. These articles are best for patients who want a general overview and who prefer short, easy-to-read materials.

Patient information: Epinephrine auto-injectors (The Basics)
Patient information: Anaphylaxis (The Basics)
Patient information: Angioedema (The Basics)
Patient information: Insect allergy (The Basics)
Patient information: Allergy skin testing (The Basics)
Patient information: Peanut allergy (The Basics)
Patient information: Drug allergy (The Basics)
Patient information: Allergy shots (The Basics)

Beyond the Basics — Beyond the Basics patient education pieces are longer, more sophisticated, and more detailed. These articles are best for patients who want in-depth information and are comfortable with some medical jargon.

Patient information: Anaphylaxis symptoms and diagnosis (Beyond the Basics)

Professional level information — Professional level articles are designed to keep doctors and other health professionals up-to-date on the latest medical findings. These articles are thorough, long, and complex, and they contain multiple references to the research on which they are based. Professional level articles are best for people who are comfortable with a lot of medical terminology and who want to read the same materials their doctors are reading.

Anaphylaxis: Rapid recognition and treatment
Bee, yellow jacket, wasp, and other Hymenoptera stings: Reaction types and acute management
Hereditary angioedema: Epidemiology, clinical manifestations, exacerbating factors, and prognosis
Clinical manifestations of food allergy: An overview
Diagnosis of Hymenoptera venom allergy
Diagnostic evaluation of food allergy
Drug eruptions
Fatal anaphylaxis
Food allergy in schools and camps
Food-induced anaphylaxis
History and physical examination in the patient with possible food allergy
Laboratory tests to support the clinical diagnosis of anaphylaxis
Pathophysiology of anaphylaxis
Prescribing epinephrine for anaphylaxis self-treatment
Hereditary angioedema: Treatment of acute attacks
Anaphylaxis in infants

The following organizations also provide reliable health information.

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Literature review current through: Mar 2014. | This topic last updated: Feb 19, 2013.
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All topics are updated as new information becomes available. Our peer review process typically takes one to six weeks depending on the issue.