What does epinephrin mean?
Epinephrin — more commonly spelled epinephrine and known popularly as adrenaline — is a hormone and neurotransmitter produced chiefly by the adrenal glands, which sit atop the kidneys. Released in response to stress, fear, or excitement, it triggers the body's 'fight-or-flight' response: heart rate and blood pressure rise, airways open, blood sugar increases, and blood flow shifts toward the muscles. In medicine, epinephrin is indispensable as an injectable drug, most famously delivered through auto-injectors such as EpiPens to reverse life-threatening anaphylaxis, and it is also used in cardiac arrest and severe asthma emergencies. The term derives from Greek roots meaning 'upon the kidney,' reflecting the gland where it was first identified. Though the shorter form "epinephrin" appears in older literature, modern medical writing overwhelmingly prefers "epinephrine."
A hormone and neurotransmitter produced by the adrenal glands that raises heart rate, blood pressure, and blood glucose as part of the body's fight-or-flight response; also known as adrenaline.
"During the emergency, her body flooded with epinephrin, sharpening her senses and quickening her pulse."
The spelling "epinephrin" is an older variant; modern usage strongly favors "epinephrine."
A medicinal preparation of this hormone, injected to treat anaphylaxis, cardiac arrest, and severe asthma attacks.
"The doctor prescribed an epinephrin auto-injector for the patient with a life-threatening bee allergy."
Rarely pluralized, as the hormone is treated as an uncountable mass noun; the plural would appear only when referring to different preparations or formulations.
"Different pharmaceutical companies produce various synthetic epinephrins for clinical use."
Your body can brew its own life-saving drug in seconds — the same chemical sold as the EpiPen's contents is what floods your bloodstream when you're terrified.
Reviewed by Deb Chak, Editor. AI-assisted content curated by RJS Tech Solutions LLP.
Etymology of epinephrin
Epinephrin comes from the Greek roots epi- ('upon' or 'on') and nephros ('kidney'), referring to its production by the adrenal glands located on top of the kidneys. The word was coined around the turn of the 20th century, when Japanese chemist Jokichi Takamine first isolated the pure hormone in 1900–1901 and named it after the anatomical position of its source. It shares its root with other kidney-related terms such as nephron, nephritis, and nephrology.
Related word forms
How epinephrin is actually used
"Epinephrin" is an older, shortened spelling of "epinephrine," which is now the standard form in both medical and general usage; "adrenaline" is the more common everyday term, especially in British English, while "epinephrine" predominates in North American clinical contexts.
Easily confused with epinephrin
Norepinephrine is a related but distinct catecholamine that acts mainly as a neurotransmitter and raises blood pressure via vasoconstriction, whereas epinephrine has stronger effects on heart rate and is the primary treatment for anaphylaxis.