Epinephrine (medication)
Life-saving medication for anaphylaxis and cardiac arrest.
Last updated
Epinephrine, also known as adrenaline, is both a naturally occurring hormone and a synthetic medication. As a medication, it is employed to address a range of acute conditions, most notably anaphylaxis, cardiac arrest, asthma exacerbations when other treatments fail, and superficial bleeding. Inhaled forms can also alleviate symptoms of croup.
Anaphylaxis
The drug is administered through several routes: intravenously, via intramuscular injection, by inhalation, or through subcutaneous injection. Common side effects include shakiness, anxiety, and sweating, while more serious potential effects involve a rapid heart rate, elevated blood pressure, and occasionally an abnormal heart rhythm. Its safety during pregnancy and breastfeeding remains unclear, though the benefits to the mother are considered.
The body naturally produces epinephrine in the adrenal glands and a small number of brain neurons, where it functions as a neurotransmitter. It is central to the fight-or-flight response, increasing blood flow to muscles, cardiac output, pupil dilation, and blood sugar levels by acting on alpha and beta receptors. While the substance is found across many animals and some single-celled organisms, the medication is manufactured synthetically. The hormone was first isolated by Jōkichi Takamine in 1901 and entered medical use in 1905.
It is listed on the World Health Organization's Essential Medicines list and is available as a generic. In the United States during 2023, it ranked as the 247th most prescribed medication, with over one million prescriptions. The term "epinephrine" derives from Greek roots meaning "on" and "kidney," referencing the adrenal glands' location above the kidneys.
For anaphylaxis, epinephrine is considered the sole life-saving treatment, commonly delivered via autoinjector in a 0.3 mg dose. Intramuscular injection is preferred over subcutaneous due to a faster and higher pharmacokinetic profile, though injection depth can be complicated by varying subcutaneous fat. In August 2024, a nasal spray formulation was approved in the U.S. for emergency allergic reactions, including anaphylaxis, in adults and children over a certain weight, with the indication expanded to younger children in March 2025. This approval was based on studies showing comparable blood concentrations and physiological effects to injected epinephrine.
Lore & Background
In the body, it is produced by the adrenal glands and a small number of brain neurons, where it functions as a neurotransmitter, playing a central role in the fight-or-flight response by increasing blood flow to muscles, heart output, pupil dilation, and blood sugar through its effects on alpha and beta receptors. While the substance is found in many animals and some single-celled organisms, the medication is manufactured synthetically. As a drug, it is administered intravenously, by injection into a muscle, by inhalation, or by injection just under the skin. Its medical uses include treating anaphylaxis, cardiac arrest, asthma, superficial bleeding, and improving symptoms of croup when inhaled.
Common side effects include shakiness, anxiety, and sweating, and it may cause a fast heart rate, high blood pressure, or occasionally an abnormal heart rhythm. The safety of its use during pregnancy and breastfeeding is unclear. The medication was first isolated by Jōkichi Takamine in 1901 and entered medical use in 1905. The name derives from the Ancient Greek for "on" and "kidney," referencing the location of the adrenal glands above the kidneys.
Reader's Guide
Epinephrine is the only life-saving treatment for anaphylaxis, and it is also used for cardiac arrest, asthma when other treatments are not effective, and superficial bleeding. Inhaled epinephrine may improve symptoms of croup. While it improves return of spontaneous circulation in cardiac arrest, it has not been shown to improve long-term survival or mental function after recovery.
Common side effects include shakiness, anxiety, and sweating; a fast heart rate and high blood pressure may occur, and occasionally an abnormal heart rhythm. Epinephrine is produced synthetically and is not harvested from animals. Its significance lies in its essential role in emergency medicine, particularly for anaphylaxis, and its inclusion on the WHO Essential Medicines list underscores its global importance.
More in Addictive Substances & Medications
Sources
Compiled from Wikipedia and the sources listed below. Text from Wikipedia is available under CC BY-SA 4.0; this entry is adapted from it.
- Wikipedia: Epinephrine (medication) (CC BY-SA 4.0).
Spotted an error? Know more?
Reader corrections go straight into our review queue. Suggest an edit · How this site is sourced