An autoinjector (or auto-injector) is a medical device for injection of a premeasured dose of a particular drug. Most autoinjectors are one-use, disposable, spring-loaded syringes (prefilled syringes). By design, autoinjectors are easy to use and are intended for self-administration by patients, administration by untrained personnel, or easy use by healthcare professionals; they can also overcome the hesitation associated with self-administration using a needle. [1] The site of injection depends on the drug, but it typically is administered into the thigh or the buttocks.[ citation needed ]
Autoinjectors are sharps waste.[ citation needed ]
Automatic syringes are known since the 1910s, [2] and many spring-loaded devices with needle protectors were patented in the first half of the 20th century, [3] but it was not until 1970s when they became economically feasible to mass-produce (simple syrettes were used instead before). In 2023 an open source autoinjector was developed that could be digitally replicated with a low cost desktop 3D printer. [4] It was tested against the then current standard (ISO 11608–1:2022) [5] for needle-based injection systems and found to cost less than mass manufactured systems. [4]
Designs exist for both intramuscular and subcutaneous injection. Disposable autoinjectors commonly use a pre-loaded spring as a power source. This spring and the associated mechanical components form a one-shot linear actuator.[ citation needed ] When triggered the actuator drives a three-step sequence:[ citation needed ]
Some injectors are triggered by simply pushing the nose ring against the injection site. In these designs, the protective cap is the primary safety. Other designs use a safety mechanism similar to nail guns: The injection is triggered by pushing the nose ring against the injection site and simultaneously, while applying pressure, pushing a trigger button at the rear end of the device.[ citation needed ]
Since spent autoinjectors contain a hypodermic needle, they pose a potential biohazard to waste management workers. Hence the protective cap is designed not only to protect the drug and keep the needle sterile but also to provide adequate sharps waste confinement after disposal.[ citation needed ]
Injectors intended for application through layers of clothing may feature an adjustable injection depth. Other typical features include: A drug inspection window, a color-coded spent indicator, and an audible click after the injection has finished.[ citation needed ]
Military uses include:
Another design has a shape and size of a smartphone which can be put into a pocket. This design also has a retractable needle and automated voice instructions to assist the users on how to correctly use the autoinjector. The "Auvi-Q" epinephrine autoinjector uses this design. [8]
A newer variant of the autoinjector is the gas jet autoinjector, which contains a cylinder of pressurized gas and propels a fine jet of liquid through the skin without using a needle. This has the advantage that patients who fear needles are more accepting of using these devices. The autoinjector can be reloaded, and various doses or different drugs can be used, although the only widespread application to date has been for the administration of insulin in the treatment of diabetes. [9] [10]
A syringe is a simple reciprocating pump consisting of a plunger that fits tightly within a cylindrical tube called a barrel. The plunger can be linearly pulled and pushed along the inside of the tube, allowing the syringe to take in and expel liquid or gas through a discharge orifice at the front (open) end of the tube. The open end of the syringe may be fitted with a hypodermic needle, a nozzle or tubing to direct the flow into and out of the barrel. Syringes are frequently used in clinical medicine to administer injections, infuse intravenous therapy into the bloodstream, apply compounds such as glue or lubricant, and draw/measure liquids. There are also prefilled syringes.
A local anesthetic (LA) is a medication that causes absence of all sensation in a specific body part without loss of consciousness, providing local anesthesia, as opposed to a general anesthetic, which eliminates all sensation in the entire body and causes unconsciousness. Local anesthetics are most commonly used to eliminate pain during or after surgery. When it is used on specific nerve pathways, paralysis also can be induced.
An epinephrine autoinjector is a medical device for injecting a measured dose or doses of epinephrine (adrenaline) by means of autoinjector technology. It is most often used for the treatment of anaphylaxis. The first epinephrine autoinjector was brought to market in 1983.
A hypodermic needle, one of a category of medical tools which enter the skin, called sharps, is a very thin, hollow tube with one sharp tip. It is commonly used with a syringe, a hand-operated device with a plunger, to inject substances into the body or extract fluids from the body. Large-bore hypodermic intervention is especially useful in catastrophic blood loss or treating shock.
Subcutaneous administration is the insertion of medications beneath the skin either by injection or infusion.
Intramuscular injection, often abbreviated IM, is the injection of a substance into a muscle. In medicine, it is one of several methods for parenteral administration of medications. Intramuscular injection may be preferred because muscles have larger and more numerous blood vessels than subcutaneous tissue, leading to faster absorption than subcutaneous or intradermal injections. Medication administered via intramuscular injection is not subject to the first-pass metabolism effect which affects oral medications.
An injection is the act of administering a liquid, especially a drug, into a person's body using a needle and a syringe. An injection is considered a form of parenteral drug administration; it does not involve absorption in the digestive tract. This allows the medication to be absorbed more rapidly and avoid the first pass effect. There are many types of injection, which are generally named after the body tissue the injection is administered into. This includes common injections such as subcutaneous, intramuscular, and intravenous injections, as well as less common injections such as intraperitoneal, intraosseous, intracardiac, intraarticular, and intracavernous injections.
A syrette is a single-use device for injecting liquid through a needle. It is similar to a syringe except that it has a sealed squeeze tube instead of a rigid tube and piston. It was developed by the pharmaceutical manufacturer E.R. Squibb & Sons just prior to World War II (WWII).
Sharps waste is a form of biomedical waste composed of used "sharps", which includes any device or object used to puncture or lacerate the skin. Sharps waste is classified as biohazardous waste and must be carefully handled. Common medical materials treated as sharps waste are hypodermic needles, disposable scalpels and blades, contaminated glass and certain plastics, and guidewires used in surgery.
Drug injection is a method of introducing a drug into the bloodstream via a hollow hypodermic needle, which is pierced through the skin into the body. Intravenous therapy, a form of drug injection, is universally practiced in modernized medical care. As of 2004, there were 13.2 million people worldwide who self-administered injection drugs outside of medical supervision, of which 22% are from developed countries.
In the United States military, the Mark I NAAK, or MARK I Kit, 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 nerve agents tabun (GA), sarin (GB), soman (GD) and VX.
Dental anesthesia is the application of anesthesia to dentistry. It includes local anesthetics, sedation, and general anesthesia.
Charles Gabriel Pravaz a French orthopedic surgeon, pioneered the hypodermic syringe.
An injection port is a medical device used for the administration of insulin or other physician-approved medicine into the subcutaneous tissue. The device is similar to infusion sets used by insulin pumps, except it is configured to receive a syringe instead of a tubing system. An injection port is usually a disposable device applied by the patient and worn for period of 3–5 days. When giving shots via an injection port, the needle stays above the surface of the skin. Medication is delivered via a short soft cannula. An injection port can be used in conjunction with multiple daily injections of insulin by people with diabetes. It can also be used for the subcutaneous administration of any other physician prescribed medication.
An ATNAA is any of a variety of autoinjectors in use with the US Armed Forces. An autoinjector is a medical device designed to deliver a single dose of a particular drug.
The carpuject is a syringe device for the administration of injectable fluid medication. It was patented by the Sterling Drug Company, which became the Sterling Winthrop, after World War II. It is designed with a luer-lock device to accept a sterile hypodermic needle or to be linked directly to intravenous tubing line. The product can deliver an intravenous or intramuscular injection by means of a holder which attaches to the barrel and plunger to the barrel plug. Medication is prefilled into the syringe barrel. When the plug at the end of the barrel is advanced to the head of the barrel it discharges and releases the contents through the needle or into the lumen of the tubing.
Intradermal injection is a shallow or superficial injection of a substance into the dermis, which is located between the epidermis and the hypodermis. For certain substances, administration via an ID route can result in a faster systemic uptake compared with subcutaneous injections, leading to a stronger immune response to vaccinations, immunology and novel cancer treatments, and faster drug uptake. Additionally, since administration is closer to the surface of the skin, the body's reaction to substances is more easily visible. However, due to complexity of the procedure compared to subcutaneous injection and intramuscular injection, administration via ID is relatively rare, and is only used for tuberculosis and allergy tests, monkeypox vaccination, and certain therapies.
A low dead space syringe (LDSS) or low dead-volume syringe is a type of syringe with a design that seeks to limit dead space that exists between the syringe hub and needle.
Charles Hunter was an English physician best known for coining the word "hypodermic" and for realising that injections of morphine could relieve pain anywhere in the body, regardless of where the injection was delivered.
An injector pen is a device used for injecting medication under the skin. First introduced in the 1980s, injector pens are designed to make injectable medication easier and more convenient to use, thus increasing patient adherence. The primary difference between injector pens and traditional vial and syringe administration is the easier use of an injector pen by people with low dexterity, poor vision, or who need portability to administer medicine on time. Injector pens also decrease the fear or adversity towards self-injection of medications, which increases the likelihood that a person takes the medication.