An epinephrine autoinjector is a medical device used to deliver a measured dose of epinephrine (commonly known as adrenalin) using autoinjector technology, most frequently for the treatment of acute allergic reactions to avoid or treat the onset of anaphylactic shock. Trade names for this device include EpiPen, Anapen and Twinject.
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Description
The devices contain a spring-loaded needle that shoots through a membrane in the tip and into the recipient's body to deliver the medication.
Epinephrine autoinjectors contain a pre-determined dose of epinephrine, usually between 0.3 mg[1][2] and 0.5 mg[1][3] of active ingredient at a concentration of 1:1000. Manufacturers have also made paediatric dosed versions available at 0.15 mg of active ingredient,[1][4] and there is also a version which contains two individual doses, in case a repeated application is required, sold under the trade name Twinject.[5]
The autoinjectors are regulated medical devices and in most jurisdictions require a medical prescription. In Canada, EpiPens may be purchased without a prescription, but they are kept behind pharmacy counters.
Usage
After activation the patient holds the device in place for 10 seconds as the epinephrine is delivered. This gives the drug enough time to be absorbed by the body's muscles and diffused into the bloodstream. Using the device intravenously is highly discouraged, and can even be lethal as epinephrine is a local vascular constrictor, and use intravenously can restrict blood flow to the area of the injection site, causing subsequent damage to extremities. Additionally, intravenous administration of the epinephrine can cause ventricular tachycardia, or dangerously rapid heartbeat.[6] After administering the device, patients are advised to seek immediate medical attention.
1998 Recall
On May 8 1998, a voluntary Class I recall took place in a number of countries (the United States, Germany, Israel, Denmark, Canada, Turkey, Australia, Greece and South Africa). Epipen (0.3 mg) and Epipen Jr. (0.15 mg) epinephrine auto-injectors were recalled because certain devices originating from specific production lots were found to be ineffective in delivering medication and treating anaphylaxis.[7] This issue was resolved within the same year.
Long-term effectiveness
None of these devices prevents future episodes of anaphylaxis, but patients who experience severe or life-threatening reactions may be treated with a series of allergy injections composed of increasing concentrations of naturally occurring substances such as venom to provide excellent and usually life-long protections against adverse effects of future insect stings: these injections are astonishingly dilute—a billion-fold or more is common.[8]
Origin
The EpiPen was originally derived from the ComboPen, a product developed for the military for treatment for exposure to nerve agents. The inventor of the ComboPen and the EpiPen was Sheldon Kaplan, who died in September 2009.[9]
See also
References
- ^ a b c http://www.epipen.com/epipen_dosing.aspx
- ^ "Anapen 300 product information sheet". Lincoln Medical Ltd. http://www.anapen.co.uk/downloads/SUMMARY%20OF%20PRODUCT%20CHARACTERISTICS%20ANAPEN%20300.doc.
- ^ "Anapen 500 product information sheet". Lincoln Medical Ltd. http://www.anapen.co.uk/downloads/SUMMARY%20OF%20PRODUCT%20CHARACTERISTICS%20ANAPEN%20500.doc.
- ^ "Anapen 150 product information sheet". Lincoln Medical Ltd. http://www.anapen.co.uk/downloads/SUMMARY%20OF%20PRODUCT%20CHARACTERISTICS%20ANAPEN%20150.doc.
- ^ Verus Pharmaceuticals Announces U.S. Launch of Twinject for Anaphylaxis
- ^ http://www.bmj.com/cgi/content/full/326/7389/589
- ^ http://www.fda.gov/MEDWATCH/safety/1998/epipen.htm
- ^ Resiman, R (August 1994). "Insect Stings". New England Journal of Medicine 26: 523–7. doi:. PMID 8041420.
- ^ http://www.tampabay.com/news/humaninterest/epipen-inventor-helped-millions-and-died-in-obscurity/1038756
- The Anaphylaxis Campaign. Accessed on March 19, 2007.
- BMJ Clinical Review of Epinephrine Administration. Accessed on March 19, 2007.
External links
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