Epinephrine, also known as adrenaline, is a hormone and neurotransmitter that is released by the adrenal glands in response to stress. It is responsible for the body's fight-or-flight response, increasing heart rate, blood pressure, and energy levels. It also plays a role in regulating metabolism and digestion. EPINEPHRINE is used medically to treat a variety of conditions, including asthma, anaphylaxis, and cardiac arrest.