Epinephrine, also known as adrenaline, is a hormone and medication that plays an important role in regulating visceral functions and is involved in the bodys "fight-or-flight" response. It is produced by the adrenal glands and is a neurotransmitter that helps transmit nerve signals across nerve endings to another nerve cell, muscle cell, or gland cell. Epinephrine is used along with emergency medical treatment to treat life-threatening allergic reactions caused by insect bites or stings, foods, medications, latex, and other causes. It is also used to treat life-threatening low blood pressure associated with septic shock in hospitalized adults. Epinephrine is a sympathomimetic catecholamine that exerts its pharmacologic effects on both alpha and beta-adrenergic receptors using a G protein-linked second messenger system. It has a greater affinity for beta receptors in small doses, but large doses produce selective action on alpha receptors. Epinephrine is the only drug that can reverse symptoms of anaphylaxis and is considered life-saving medication. It is the first-line treatment for anaphylaxis and should be used before asthma inhalers, antihistamines, or any other medications.