Epinephrine, also known as adrenaline, is a hormone and neurotransmitter produced by the adrenal glands. It plays a crucial role in the bodyโs fight-or-flight response, stimulating adrenergic receptors to increase heart rate, dilate airways, and mobilize energy stores. Understanding epinephrine is vital as it directly relates to adrenergic drugs, which mimic its effects, and adrenergic blockers, which inhibit its action.