Subcutaneous Injection: Instructions & Recommendations

Subcutaneous injection is a technique that involves using a needle to inject medication into the adipose tissue (fat layer) below the skin, typically in the abdomen.

The subcutaneous route is ideal for the administration of injectable medications at home. It allows medication to be absorbed gradually in the body and is easier to perform and carries fewer risks than an intramuscular injection.

Subcutaneous injection is typically used to administer insulin or enoxaparin (heparin) at home. Enoxaparin is commonly prescribed following surgery or for management of conditions related to blood clots, such as stroke or deep venous thrombosis (DVT).

Correct technique

Administering a subcutaneous injection is relatively simple, but it is important to follow the proper steps:

1. Gather your supplies, syringe with the medication, gauze squares, and alcohol pads;
2. Wash your hands before performing the injection;
3. Clean your skin with an alcohol pad, to disinfect the injection area;
4. Gently pinch a fold of skin, securing it between your thumb and index finger on your non-dominant hand;
5. Insert the needle into the skinfold (ideally at a 90º angle) with your dominant hand in one swift motion, while maintaining a good hold of the skin with your non-dominant hand;
6. Push down slowly on the plunger, until all of the medication is administered;
7. Remove the needle, release the fold of skin, and apply light pressure to the area with an alcohol pad;
8. Dispose of the used syringe and needle in a sharps container, out of the reach of children. Never attempt to put the cap back on a used syringe.

Subcutaneous injections can be given in the abdomen, thigh, or upper arm. It is important to rotate the injection site, allowing at least 1 cm between one injection and the next.

People who are very thin or who have very little body fat may have to inject the needle only two-thirds of the way in to avoid hitting the muscle. It is important to avoiding pinching the skin too hard in order to avoiding pulling muscle up with the skin.

Injection sites

The best areas to administer a subcutaneous injection are those where there is an accumulation of body fat. The most common sites are:

1. Abdomen

The area around the umbilicus (navel, or belly button) has one of largest stores of body fat. That is why it is often used as the primary site for subcutaneous injections. It is also nearly impossible to grab the ab muscles when pinching the skin into a skinfold, making this a very safe site for injection. 

The most important thing to remember is to administer the injection at least 1 cm from the umbilicus.

2. Arm

The outer surface of the upper arm can also be used for subcutaneous injections, as this is another area where fat accumulates. 

It may be more difficult to avoid the muscle in this region. For that reason it is important to make sure you are only pinching the fat layer before administering the injection.

3. Thighs

A subcutaneous injection can also be given in the thigh, as it is another area where fat is stored, especially in women. While it is not the most common site for injections, the thigh can be a good option when the abdomen and arms have been used multiple times in a row. 

Potential complications

Subcutaneous injections are quite safe, however like any type of injection there are potential complications. These include:

• Pain at the injection site;
• Redness of the skin at the injection site;
• Minor localized swelling;
• Drainage of fluid.

These complications can happen in any case but are more common when injections are required over a long period of time.

It is important to seek medical attention for the above symptoms if they do not resolve on their own within a few hours.