Epinephrine, also known as adrenaline, is a medication and hormone.[10][11] As a medication, it is used to treat several conditions, including anaphylaxis, cardiac arrest, asthma, and superficial bleeding.[8]Inhaled epinephrine may be used to improve the symptoms of croup.[12] It may also be used for asthma when other treatments are not effective.[8] It is given intravenously, by injection into a muscle, by inhalation, or by injection just under the skin.[8]
Common side effects include shakiness, anxiety, and sweating.[8] A fast heart rate and high blood pressure may occur.[8] Occasionally, it may result in an abnormal heart rhythm.[8] While the safety of its use during pregnancy and breastfeeding is unclear, the benefits to the mother must be taken into account.[8]
The word epinephrine is formed from the Ancient Greek ἐπι- (epi-, "on") and νεφρός (nephros, "kidney") because the adrenal glands, where it is produced, are located just above the kidneys.[24]
Epinephrine is the only life-saving treatment for anaphylaxis.[30] The commonly used epinephrine autoinjector delivers a 0.3 mg epinephrine injection (0.3 mL, 1:1000).[citation needed] It is indicated in the emergency treatment of allergic reactions, including anaphylaxis to stings, contrast agents, medicines, or people with a history of anaphylactic reactions to known triggers.[citation needed] A lower-strength product is available for children.[31][32][33][34]
Intramuscular injection can be complicated in that the depth of subcutaneous fat varies and may result in subcutaneous injection, or may be injected intravenously in error, or the wrong strength used.[35][36] Intramuscular injection gives a faster and higher pharmacokinetic profile compared to subcutaneous injection.[37]
In August 2024, an epinephrine nasal spray (brand name Neffy) was approved in the United States for the emergency treatment of allergic reactions (type I), including those that are life-threatening (anaphylaxis), in people who weigh at least 30 kilograms (66 lb).[2][30][38] It is the first nasal spray for the treatment of anaphylaxis approved by the US Food and Drug Administration (FDA).[30]
The approval of epinephrine nasal spray is based on four studies in 175 healthy adults, without anaphylaxis, that measured the epinephrine concentrations in the blood following administration of epinephrine nasal spray or approved epinephrine injection products.[30] Results from these studies showed comparable epinephrine blood concentrations between epinephrine nasal spray and approved epinephrine injection products.[30] Epinephrine nasal spray also demonstrated similar increases in blood pressure and heart rate as epinephrine injection products, two critical effects of epinephrine in the treatment of anaphylaxis.[30] A study of epinephrine nasal spray in children weighing more than 66 pounds showed that epinephrine concentrations in children were similar to adults who received epinephrine nasal spray.[30]
The most common side effects of epinephrine nasal spray include throat irritation, tingling nose (intranasal paresthesia), headache, nasal discomfort, feeling jittery, tingling sensation (paresthesia), fatigue, tremor, runny nose (rhinorrhea), itchiness inside the nose (nasal pruritus), sneezing, abdominal pain, gum (gingival) pain, numbness in the mouth (hypoesthesia oral), nasal congestion, dizziness, nausea and vomiting.[30] The FDA granted the application of epinephrine nasal spray fast track designation and granted the approval of Neffy to ARS Pharmaceuticals.[30]
Asthma
Epinephrine is also used as a bronchodilator for asthma if specific β2 agonists are unavailable or ineffective.[39]
Because of the high intrinsic efficacy (receptor binding ability) of epinephrine, high drug concentrations cause adverse side effects when treating asthma. The value of using nebulized epinephrine in acute asthma is unclear.[40]
Croup
Racemic epinephrine has been used for the treatment of croup.[41][42]Racemic adrenaline is a 1:1 mixture of the two enantiomers of adrenaline.[43] The L-form is the active component.[43] Racemic adrenaline works by stimulating the alpha-adrenergic receptors in the airway, with resultant mucosal vasoconstriction and decreased subglottic edema, and by stimulating the β adrenergic receptors, with resultant relaxation of the bronchial smooth muscle.[42]
Bronchiolitis
There is a lack of consensus as to whether inhaled nebulized epinephrine is beneficial in the treatment of bronchiolitis, with most guidelines recommending against its use.[44]
Local anesthetics
When epinephrine is mixed with local anesthetics, such as bupivacaine or lidocaine, and used for local anesthesia or intrathecal injection, it prolongs the numbing effect and motor block effect of the anesthetic by up to an hour.[45] Epinephrine is frequently combined with local anesthetic and can cause panic attacks.[46]
Use is contraindicated in people on nonselective β-blockers because severe hypertension and even cerebral hemorrhage may result.[50]
The most common side effects of epinephrine nasal spray include throat irritation, tingling nose (intranasal paresthesia), headache, nasal discomfort, feeling jittery, tingling sensation (paresthesia), fatigue, tremor, runny nose (rhinorrhea), itchiness inside the nose (nasal pruritus), sneezing, abdominal pain, gum (gingival) pain, numbness in the mouth (hypoesthesia oral), nasal congestion, dizziness, nausea and vomiting.[30] The FDA granted the application of epinephrine nasal spray fast track designation and granted the approval of Neffy to ARS Pharmaceuticals.[30]
Epinephrine acts by binding to a variety of adrenergic receptors. Epinephrine is a nonselective agonist of all adrenergic receptors, including the major subtypes α1, α2, β1, β2, and β3.[50] Epinephrine's binding to these receptors triggers several metabolic changes. Binding to α-adrenergic receptors inhibits insulin secretion by the pancreas, stimulates glycogenolysis in the liver and muscle,[51] and stimulates glycolysis and inhibits insulin-mediated glycogenesis in muscle.[52][53] β adrenergic receptor binding triggers glucagon secretion in the pancreas, increased adrenocorticotropic hormone (ACTH) secretion by the pituitary gland, and increased lipolysis by adipose tissue. Together, these effects increase blood glucose and fatty acids, providing substrates for energy production within cells throughout the body.[53] In the heart, the coronary arteries have a predominance of β2 receptors, which cause vasodilation of the coronary arteries in the presence of epinephrine.[54]
Its actions increase peripheral resistance via α1 receptor-dependent vasoconstriction and increase cardiac output via its binding to β1 receptors. The goal of reducing peripheral circulation is to increase coronary and cerebral perfusion pressures and therefore increase oxygen exchange at the cellular level.[55] While epinephrine does increase aortic, cerebral, and carotid circulation pressure, it lowers carotid blood flow and end-tidal CO2 or ETCO2 levels. It appears that epinephrine may improve macrocirculation at the expense of the capillary beds where perfusion takes place.[56]
Extracts of the adrenal gland were first obtained by Polish physiologist Napoleon Cybulski in 1895. These extracts, which he called nadnerczyna, contained adrenaline and other catecholamines.[57] American ophthalmologist William H. Bates discovered adrenaline's usage for eye surgeries prior to 20 April 1896.[58] Japanese chemist Jōkichi Takamine and his assistant Keizo Uenaka independently discovered adrenaline in 1900.[59][60] In 1901, Takamine successfully isolated and purified the hormone from the adrenal glands of sheep and oxen.[61] Adrenaline was first synthesized in the laboratory by Friedrich Stolz and Henry Drysdale Dakin, independently, in 1904.[60]
Society and culture
Names
Brand names
Epinephrine is the generic name of the drug and its INNTooltip International Nonproprietary Name and USANTooltip United States Adopted Name, while adrenaline is its BANTooltip British Approved Name.[62][63][64] Epinephrine is sold under various brand names including Asthmanefrin, Micronefrin, Neffy, Nephron, VapoNefrin, and Primatene Mist, among others.[63]
Legal status
In June 2024, the Committee for Medicinal Products for Human Use of the European Medicines Agency adopted a positive opinion, recommending the granting of a marketing authorization for the medicinal product Eurneffy, intended for emergency treatment of allergic reactions (anaphylaxis) due to insect stings or bites, foods, medicinal products, and other allergens as well as idiopathic or exercise-induced anaphylaxis.[3][65][66] The applicant for this medicinal product is ARS Pharmaceuticals IRL Limited.[3] Eurneffy was approved for medical use in the European Union in August 2024.[3][4]
A common concentration for epinephrine is 2.25% w/v epinephrine in solution, which contains 22.5 mg/mL, while a 1% solution is typically used for aerosolization.[70][71]
^ abcd"European Medicines Agency". Eurneffy EPAR. 27 June 2024. Archived from the original on 29 June 2024. Retrieved 29 June 2024. Text was copied from this source which is copyright European Medicines Agency. Reproduction is authorized provided the source is acknowledged.
^El-Bahr SM, Kahlbacher H, Patzl M, Palme RG (May 2006). "Binding and clearance of radioactive adrenaline and noradrenaline in sheep blood". Veterinary Research Communications. 30 (4). Springer Science and Business Media LLC: 423–32. doi:10.1007/s11259-006-3244-1. PMID16502110. S2CID9054777.
^Franksson G, Anggård E (March 2009). "The plasma protein binding of amphetamine, catecholamines and related compounds". Acta Pharmacologica et Toxicologica. 28 (3). Wiley: 209–14. doi:10.1111/j.1600-0773.1970.tb00546.x. PMID5468075.
^ abcdefghi"Epinephrine". The American Society of Health-System Pharmacists. Archived from the original on 6 September 2015. Retrieved 15 August 2015.
^Hummel MD (2012). "Emergency Medications". In Pollak AN (ed.). Nancy Caroline's Emergency Care in the Streets (7th ed.). Burlington: Jones & Bartlett Learning. p. 557. ISBN9781449645861. Archived from the original on 8 September 2017.
^"(-)-adrenaline". Guide to Pharmacology. IUPS/BPS. Archived from the original on 1 September 2015. Retrieved 21 August 2015.
^Everard ML (February 2009). "Acute bronchiolitis and croup". Pediatric Clinics of North America. 56 (1): 119–33, x–xi. doi:10.1016/j.pcl.2008.10.007. PMID19135584.
^Malenka RC, Nestler EJ, Hyman SE (2009). "Chapter 6: Widely Projecting Systems: Monoamines, Acetylcholine, and Orexin". In Sydor A, Brown RY (eds.). Molecular Neuropharmacology: A Foundation for Clinical Neuroscience (2nd ed.). New York, USA: McGraw-Hill Medical. p. 157. ISBN9780071481274. Epinephrine occurs in only a small number of central neurons, all located in the medulla. Epinephrine is involved in visceral functions, such as the control of respiration. It is also produced by the adrenal medulla.
^World Health Organization (2019). World Health Organization model list of essential medicines: 21st list 2019. Geneva: World Health Organization. hdl:10665/325771. WHO/MVP/EMP/IAU/2019.06. License: CC BY-NC-SA 3.0 IGO.
^"Epinephrine". The American Society of Health-System Pharmacists. Archived from the original on 7 March 2011. Retrieved 3 April 2011.
^Kempton H, Vlok R, Thang C, Melhuish T, White L (March 2019). "Standard dose epinephrine versus placebo in out of hospital cardiac arrest: A systematic review and meta-analysis". The American Journal of Emergency Medicine. 37 (3): 511–517. doi:10.1016/j.ajem.2018.12.055. PMID30658877. S2CID58580872.
^Koninckx M, Buysse C, de Hoog M (June 2013). "Management of status asthmaticus in children". Paediatric Respiratory Reviews. 14 (2): 78–85. doi:10.1016/j.prrv.2013.03.003. PMID23578933.
^Abroug F, Dachraoui F, Ouanes-Besbes L (March 2016). "Our paper 20 years later: the unfulfilled promises of nebulised adrenaline in acute severe asthma". Intensive Care Medicine. 42 (3): 429–31. doi:10.1007/s00134-016-4210-1. PMID26825950. S2CID37328426.
^ abThomas LP, Friedland LR (January 1998). "The cost-effective use of nebulized racemic epinephrine in the treatment of croup". The American Journal of Emergency Medicine. 16 (1): 87–9. doi:10.1016/S0735-6757(98)90073-0. PMID9451322.
^Rahn R, Ball B (2001). Local Anesthesia in Dentistry: Articaine and Epinephrine for Dental Anesthesia (1 st ed.). Seefeld, Germany: 3M ESPE. p. 44. ISBN978-3-00-008562-8.
^Markovchick V (2007). Critical Care Secrets (fourth ed.).
^Nazir S, Lohani S, Tachamo N, Ghimire S, Poudel DR, Donato A (February 2017). "Takotsubo cardiomyopathy associated with epinephrine use: A systematic review and meta-analysis". Int. J. Cardiol. 229: 67–70. doi:10.1016/j.ijcard.2016.11.266. PMID27889211.
^ abShen H (2008). Illustrated Pharmacology Memory Cards: PharMnemonics. Minireview. p. 4. ISBN978-1-59541-101-3.
^Arnall DA, Marker JC, Conlee RK, Winder WW (June 1986). "Effect of infusing epinephrine on liver and muscle glycogenolysis during exercise in rats". The American Journal of Physiology. 250 (6 Pt 1): E641–9. doi:10.1152/ajpendo.1986.250.6.E641. PMID3521311.
^Raz I, Katz A, Spencer MK (March 1991). "Epinephrine inhibits insulin-mediated glycogenesis but enhances glycolysis in human skeletal muscle". The American Journal of Physiology. 260 (3 Pt 1): E430–5. doi:10.1152/ajpendo.1991.260.3.E430. PMID1900669.
^ abSircar S (2007). Medical Physiology. Thieme Publishing Group. p. 536. ISBN978-3-13-144061-7.