Epinephrine or adrenaline is the hormone found in Epi-Pens, which are used to treat severe allergic reactions, such as those experienced by someone who is allergic to peanuts. Epinephrine, a hormone secreted by the adrenal glands, is also used in the treatment of asthma, for certain heart problems, and in local anesthetics. EpiPens, as well as Anapens, Twinjects, and other allergy treatment injection devices all use epinephrine.
Adrenaline is released by the body in times of stress, and can lead to feelings of alertness and an energetic state. It leads to increases in blood sugar levels, blood pressure, and heart rate. Epinephrine also serves to constrict the blood vessels and dilate the air passages, among other effects. When used in local anesthetics such as lidocaine, for example, the effects of Epinephrine include restricting absorption of the anesthetic, prolonging its effectiveness.
For those with severe allergies, the primary purpose of epinephrine is to constrict the blood vessels, which slows the immune response to the allergen. Although a weakened immune system is seen as a negative in many situations, when treating a severe allergic reaction it is important to slow down the process of negative response to the allergen.
Some of the effects of anaphylatic shock include swelling, weak pulse, difficulty breathing, and dropping blood pressure. When used to stop an allergic reaction, EpiPens and similar auto-injectors release adrenaline into the blood stream, where the adrenaline reverses these symptoms by acting on two types of adrenergic receptors. When adrenaline comes into contact with alpha receptors found on the walls of the blood vessels, the vessels become narrower, which causes the blood pressure to increase and redirects blood to essential organs such as the heart and brain. Adrenaline stimulating the beta receptors, found in the lungs and heart, causes the airways to relax, making breathing easier, while stimulating the heart.
Other effects of epinephrine are undesirable and are considered side effects. These include heart palpitations, arrhythmia, or tachycardia, tremors, anxiety, headaches, hypertension, and acute pulmonary edema.