Epinephrine autoinjector
Encyclopedia
Epinephrine
Epinephrine is a hormone and a neurotransmitter. It increases heart rate, constricts blood vessels, dilates air passages and participates in the fight-or-flight response of the sympathetic nervous system. In chemical terms, adrenaline is one of a group of monoamines called the catecholamines...
(also known as adrenaline) using autoinjector
Autoinjector
An autoinjector is a medical device designed to deliver a single dose of a particular drug....
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, Twinject, Adrenaclick, Anapen, and Jext. The EpiPen was originally derived from the ComboPen
Mark I NAAK
The Mark I NAAK, or MARK I Kit, is United States military nomenclature for the "Nerve Agent Antidote Kit". It is a dual-chamber autoinjector: Two anti-nerve agent drugs — atropine sulfate and pralidoxime chloride — each in injectable form, constitute the kit. The kits are only effective against the...
, a product developed for the military for treating exposure to nerve agents.
Design
The devices contain a spring-loaded needle that exits the tip of the device (in some cases through a sterile membrane) and into the recipient's body to deliver the medication.Epinephrine autoinjectors contain a pre-determined dose of epinephrine, usually between 300 μg and 500 μg of active ingredient at a concentration of 1:1000. Manufacturers have also made pediatric dosed versions available at 150 μg of active ingredient, and there is also a version which contains two individual doses (in case a repeated application is required) sold under the trade name Twinject.
In most countries, epinephrine is a prescription drug
Prescription drug
A prescription medication is a licensed medicine that is regulated by legislation to require a medical prescription before it can be obtained. The term is used to distinguish it from over-the-counter drugs which can be obtained without a prescription...
, and therefore obtaining the device requires a prescription
Medical prescription
A prescription is a health-care program implemented by a physician or other medical practitioner in the form of instructions that govern the plan of care for an individual patient. Prescriptions may include orders to be performed by a patient, caretaker, nurse, pharmacist or other therapist....
from a doctor
Physician
A physician is a health care provider who practices the profession of medicine, which is concerned with promoting, maintaining or restoring human health through the study, diagnosis, and treatment of disease, injury and other physical and mental impairments...
. However, in some jurisdictions, epinephrine autoinjectors are an over-the-counter drug
Over-the-counter drug
Over-the-counter drugs are medicines that may be sold directly to a consumer without a prescription from a healthcare professional, as compared to prescription drugs, which may be sold only to consumers possessing a valid prescription...
and may be purchased from a pharmacy counter.
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 muscleMuscle
Muscle is a contractile tissue of animals and is derived from the mesodermal layer of embryonic germ cells. Muscle cells contain contractile filaments that move past each other and change the size of the cell. They are classified as skeletal, cardiac, or smooth muscles. Their function is to...
s and diffused into the bloodstream. Using the device intravenously is highly discouraged, and can even be lethal as epinephrine is a local vascular constrictor
Vasoconstriction
Vasoconstriction is the narrowing of the blood vessels resulting from contraction of the muscular wall of the vessels, particularly the large arteries, small arterioles and veins. The process is the opposite of vasodilation, the widening of blood vessels. The process is particularly important in...
, and used 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
Ventricular tachycardia
Ventricular tachycardia is a tachycardia, or fast heart rhythm, that originates in one of the ventricles of the heart...
, or dangerously rapid heartbeat. After administering the device, patients are advised to seek immediate medical attention.
Effectiveness
None of these devices prevent 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: the initial injections have a very low concentration, usually 1 ppb or less.On May 8, 1998, a voluntary Class I recall
Class I recall
The United States Food and Drug Administration has published certain product recall policies applicable to consumer products.-FDA-Industry Co-operation:...
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. This issue was resolved within the same year.