Autoinjector

Autoinjector

An autoinjector, also known as an auto-injector, is a medical device engineered to administer a single dose of a specific (often life-saving) medication.

Typically, autoinjectors consist of spring-loaded syringes designed for easy use, intended for self-administration by patients or by individuals without medical training. Depending on the medication, injections are typically delivered into the thigh or buttocks. Originally, autoinjectors were developed to alleviate the apprehension associated with self-administering needle-based drug delivery devices.

Before injection, the autoinjector keeps the needle tip shielded and incorporates a passive safety mechanism to prevent accidental firing. Injection depth may be adjustable or fixed, and some models include a feature for needle shield removal. With the simple press of a button, the syringe needle is automatically inserted, delivering the medication.

Certain autoinjectors offer visual indicators to confirm the complete delivery of the dose. However, autoinjectors containing glass syringes can be fragile and susceptible to contamination. To address this issue, recent advancements have explored the use of plastic syringes in autoinjector design.

Examples of autoinjectors include Anapen, EpiPens, and the recently introduced Twinject, often prescribed to individuals at risk of anaphylaxis. Additionally, Rebiject and Rebiject II autoinjectors are used for Rebif, a medication for treating Multiple Sclerosis. The SureClick autoinjector is another example, serving as a combination product for medications like Enbrel or Aranesp, used to treat arthritis or anemia, respectively.

A newer iteration of the autoinjector is the gas jet autoinjector, which utilizes a cylinder of pressurized gas to propel a fine liquid jet through the skin without a needle. This design allows for reloadable autoinjectors, accommodating various doses or medications. While its primary application thus far has been for administering insulin in diabetes treatment, it holds potential for broader medical use.