Overview Of Subcutaneous (SC) Injection

Subcutaneous (SC) injections is another form of the parenteral route of medication and are administered to the layer of skin referred to as cutis, just below the dermis and epidermis layers. They are commonly used to administer medications, especially those which cannot be administered by mouth as they would not be absorbed from the gastrointestinal tract. They are also the easiest form of parenteral administration of medication to perform by lay people, and are associated with less adverse effects such as pain or infection than other forms of injection.

Subcutaneous (SC) injection is injecting substance into behind the dermis of the skin
Subcutaneous (SC) injection

Subcutaneous tissue has few blood vessels; therefore, the medications injected undergo absorption at a slow, sustained rate. This is slower than a substance injected intravenously or into a muscle, but faster than a medication administered by mouth.

Site For Subcutaneous Injection

Subcutaneous medication can be administered to various sites, including the upper arm's outer area, abdomen avoiding a 2-inch circle around the navel, the front of the thigh, upper back, or the upper area of the buttock behind the hip bone.

Read AlsoOverview Of Intravenous (IV) Administration

Site rotation prevents the formation of lipohypertrophy or lipoatrophy in the skin. Physical exercise or application of hot or cold compresses influences the rate of drug absorption by altering local blood flow to the tissues. Any condition that impairs that blood flow to the subcutaneous tissue contradicts the use of subcutaneous injections.

Pinching is advised for thinner patients in order to lift the adipose tissue up and away from the underlying muscle and tissue. If pinching is used, release the pinch when the needle is inserted to avoid injecting into compressed tissue.

Medication For Sc

Medications commonly administered via subcutaneous injection include insulin, monoclonal antibodies, and heparin.


These medications cannot be administered orally as the molecules are too large to be absorbed in the intestines. Examples of subcutaneous medications include insulin, opioids, heparin, epinephrine, and allergy medication.

Subcutaneous Injection Methods

Subcutaneous injections are usually given at a 45- to 90-degree angle. The angle is based on the amount of subcutaneous tissue present. Generally, give shorter needles at a 90-degree angle and longer needles at a 45-degree angle. SC injections do not need to be aspirated as the likelihood of injecting into a blood vessel is small. Usually, no more than 1 ml of medication is given subcutaneously. More than 2 ml will lead to leak or inflammation.

Novel modalities of subcutaneous drug delivery include dermojets, pellet implantation, device implantation.

Equipment

The gauge of the needle used can range from 25 gauge to 27 gauge, while the length can vary between 1⁄2-inch to 5⁄8-inch for injections using a syringe and needle. For subcutaneous injections delivered using devices such as injector pens, the needle used may be as thin as 34 gauge (commonly 30-32 gauge), and as short as 3.5mm (commonly 3.5mm to 5mm). Subcutaneous injections can also be delivered via a pump system which uses a cannula inserted under the skin. 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 layer.

Read AlsoOverview Of Intramuscular (IM) Injection

Others are alcohol wipe, sterile 2 x 2 gauze pad, a new needle and syringe that are the correct size and disposable gloves (optional).

Procedure

1. Educate the patient on the procedure

2. Get all the necessary materials from equipment to the drug

3. Remove the needle cap with the non-dominant hand, pulling it straight off

3. Clean the site with an alcohol swab or antiseptic swab. Use a firm, circular motion. Allow the site to dry

4. Grasp or pinch the area surrounding the injection site, or spread the skin taut at the site

5. Hold the syringe in the dominant hand between the thumb and forefinger. Insert the needle quickly at a 45- to 90-degree angle

6. After the needle is in place, release the tissue. Move your non-dominant hand to steady and lower the end of the needle. With your dominant hand, inject the medication at a rate of 10 seconds per ml. Avoid moving the syringe

7. Withdraw the needle quickly at the same angle at which it was inserted, while supporting the surrounding tissue with your non-dominant hand

8. Using a sterile gauze, apply gentle pressure at the site after the needle is withdrawn. Do not massage the site

9. Do not recap the needle. Apply the safety shield or needle guard on the needle and dispose in a sharps container

Comments

Consultation Service