Subcutaneous administration
A subcutaneous injection is administered as a bolus into the subcutis, the layer of skin directly below the dermis and epidermis, collectively referred to as the cutis.
Subcutaneous injections are highly effective in administering medications such as insulin, morphine, diacetylmorphine and goserelin.
[1] Subcutaneous tissue has few blood vessels and so drugs injected into it are intended for slow, sustained rates of absorption, often with some amount of depot effect.
[3]: 721 Medications commonly administered via subcutaneous injection or infusion include insulin, live vaccines, monoclonal antibodies, and heparin.
[7] Recreational drugs reported to be administered subcutaneously have included cocaine,[8] mephedrone,[9] and amphetamine derivatives such as PMMA.
This term encompasses any combination of redness, swelling, itching, bruising, or other irritation that does not spread beyond the immediate vicinity of the injection.
Rotating the injection site is the primary method of preventing changes in tissue structure from insulin administration.
[16] Subcutaneous heparin-based anticoagulation may also lead to necrosis of the surrounding skin or lesions, most commonly when injected in the abdomen.
This is seen with the subcutaneous injection of triptans for migraine headache,[20] medroxyprogesterone acetate for contraception,[21] as well as many monoclonal antibodies.
In most cases, injection site reactions are self-limiting and resolve on their own after a short time without treatment, and do not require the medication to be discontinued.
The appropriate injection angle is based on the length of needle used, and the depth of the subcutaneous fat in the skin of the specific person.
The specific needle size/length, as well as appropriateness of a device such as a pen or pump, is based on the characteristics of a person's skin layers.
People who are to self-inject medicine subcutaneously should be trained how to evaluate and rotate the injection site if complications or contraindications arise.
Self-administration by subcutaneous injection generally does not require disinfection of the skin outside of a hospital setting as the risk of infection is extremely low, but instead it is recommended to ensure that the site and person's hands are simply clean prior to administration.
Kane was looking for a technique that was as fast as intravenous infusion but not so risky to use on trauma patients in unhygienic conditions in the field.
