Epinephrine for the treatment of anaphylaxis
Epinephrine is the primary initial treatment for anaphylactic reactions which might be caused by food allergies. This drug requires a prescription from a doctor and should be carried at all times by people at risk of developing anaphylaxis, whether from food or other allergens, such as bee stings. Epinephrine is usually delivered with “autoinjectors” which are designed to puncture the skin and inject the drug into the muscle through a needle.
Epinephrine, also called adrenaline, is a hormone which is released by the body in its “fight-or-flight” response. When you get scared or startled and you feel your heart racing, this is due to epinephrine. It counteracts the effects of anaphylaxis by acting both as a bronchodilator, which increases the size of the airways helping patients to breath better, and as a vasoconstrictor, squeezing down the diameter of blood vessels which increases the blood pressure. The dose of epinephrine is dependent on the weight of the individual, so not all children will necessarily have the same dose injector prescribed.
Epinephrine is “self-administered” so anyone who might need to deliver the drug (the at-risk child, parents, grandparents, teachers, etc.) should be taught how to use the autoinjector to decrease some of the fear and uncertainty when it comes time to use it. The most common site recommend for delivery of the drug is into the mid-outer thigh with the injector needle to be held in place for at least 3 seconds (depending on the device used). These devices are designed to penetrate clothes, provided that there is no metal or other hard substances (credit cards, cell phones, etc.) underneath the clothes. Here is a video about how to use an epinephrine autoinjector.
A good way to practice the injection process is by taking a training injector (or an expired injector) and doing a trial injection on fruit such as orange or grapefruit. Otherwise, the sound and feel of the spring releasing the needle can be startling to someone doing it for the first time, which might result in an incomplete delivery of the drug. We once heard the story of a mother who was asked by her daughter, who was in her twenties, to deliver the injection because the daughter was scared. In a panic, the mother held the injector upside down with her thumb covering the area that the needle sprang out of the device. The mother received the injection into her thumb and the daughter did not receive any epinephrine. They both ended up in the hospital in a great deal of distress, Fortunately, both recovered well, but with considerable embarrassment.
One of the most important questions surrounding epinephrine is in regards to WHEN to use the injector. This can be a difficult question to answer because allergic reactions can be unpredictable with one exposure leading to a mild reaction and the next one leading to a severe one. In addition, anaphylactic reactions can progress rapidly and delayed use can result in the drug being ineffective. For mild allergic reactions, antihistamines and asthma inhalers may appear to help, but sometimes the effects are temporary. Also, antihistamines may take awhile to start working as this needs to be ingested, and vomiting up the drug can be a common problem. It is best to review when epinephrine should be used with your doctor, but clearly, if a person is having any difficulty breathing, feeling tightness in the throat, lightheadedness or having uncontrolled vomiting, immediate use of epinephrine is warranted.
Once epinephrine is delivered, the patient needs to be taken immediately to the emergency department of the nearest hospital or medical facility. These patients require observation because there is the possibility that one injection is not enough and a second dose may be required if the symptoms worsen. Also, if the drug fails to work, patients may require intubation, which is placement of a breathing tube into the airway, and this can only be done by medical professionals.
If patients cannot be taken to a hospital immediately or there is a wait for an ambulance to arrive, patients who are lightheaded need to be placed on their backs with their legs elevated. This will allow better blood flow to the head and other vital organs. Patients who have “passed out” should NOT have their heads elevated.
Epinephrine autoinjectors do expire, so check the date of expiration on a regular basis, INCLUDING when you receive the injector. The pharmacy should not be giving you a injector that is near the expiration date; otherwise, send it back and demand another one. However, if a reaction is happening, and an expired injector is the only one that is available, the injection should be delivered anyways, because the injector will likely retain some, if not most, of its effectiveness for a few years after expiration.