Epinephrine, also known as adrenaline, is a hormone and neurotransmitter and produced by the adrenal glands that can also be used as a drug due to its various important functions. Though it has long been used in the treatment of hypersensitivity reactions, epinephrine in the auto-injector form (EpiPen) has been available since 1987 in the USA. Many new products/biosimilars and dosage routes have been approved under various names over the last several decades. On August 16, 2018, Teva Pharmaceuticals USA gained approval to market its generic epinephrine auto-injector in 0.3 mg and 0.15 mg strengths. Dosage delivery routes for epinephrine include intravenous, inhalation, nebulization, intramuscular injection, and subcutaneous injection. In general, the most common uses of parenteral epinephrine are to relieve respiratory distress due to bronchospasm, to provide rapid relief of hypersensitivity (anaphylactic or anaphylactoid) reactions to drugs, animal serums and other allergens, and to prolong the action of infiltration anesthetics. In addition to the above functions, epinephrine is the primary drug administered during cardiopulmonary resuscitation (CPR) to reverse cardiac arrest,. It can be used in severe cases of croup.