Subcutaneous and intramuscular injections
Subcutaneous injections
Subcutaneous (SUBQ) injections involve placing medication into the subcutaneous layer under the dermis. The subcutaneous layer has fewer blood vessels than the muscles do. The medication absorbs more slowly in the subcutaneous layer compared with medications injected into the muscles. The patient may complain of discomfort or pain with a subcutaneous injection. Subcutaneous tissue contains pain receptors.
Common medications given via the subcutaneous route include several vaccines (e.g., MMR, varicella, and polio), enoxaparin (Lovenox), heparin, and insulin.
Abbreviations for subcutaneous injections
There have been many abbreviations for subcutaneous injections over the years. Some may still be used in practice, although they are not recommended. The Institute for Safe Medication Practices (ISMP) discourages the use of SC, SQ, and sub q. Healthcare professionals should use SUBQ or subcutaneously. For more information, refer to the ISMP website at www.ismp.org/recommendations/error-prone-abbreviations-list.
Administration techniques
When a SUBQ injection is given, the angle depends on the needle length. If a 5⁄8-inch needle is used, the medical assistant should use a 45-degree angle. If a 1⁄2-inch needle is used, a 90-degree angle should be applied. It is important to pinch up the tissue with the index finger and thumb of the nondominant hand. This ensures that the injection is given in the subcutaneous tissue.
Aspiration
Aspiration is used to check if the needle is in a blood vessel. This is done once before the medication is given. (The aspiration technique will be discussed in detail in the Intramuscular Injections section, presented later in the chapter.) With SUBQ injections, the aspiration should be done if the medication manufacturer recommends it. It should also be done if it is part of the facility’s policy.
Insulin is not aspirated. SUBQ immunizations do not need to be aspirated, as recommended by the CDC. Anticoagulants, such as enoxaparin and heparin, are administered in the abdomen. They are not aspirated, as specified by the manufacturers.
Subcutaneous sites
Typically, three SUBQ sites are used in ambulatory care:
- Abdominal site: Have the patient remove the clothing in that area. Provide a drape sheet if needed to protect the patient’s modesty. The site is located below the costal margins to the iliac crests. Stay 2 inches away from the umbilicus. It is important to stay away from the waistline and any scars. The patient may have more discomfort if the injection is given at the waistline due to the rubbing of clothing.
- Outer posterior aspect of the upper arm: Expose the arm. The outer posterior site extends from 3 inches above the elbow to about 3 fingerbreadths below the acromion process. It is important to stay away from the shoulder area.
- Anterior aspect of the thigh: Place one hand above the knee and the other hand below the greater trochanter. The site is the middle one-third of the thigh. The site extends from the front midline to the back midline, wrapping around the outer thigh. Usually, only the middle one-third—from the front midline to the outer thigh—is used. Injections are not done on the back of the leg because sitting would irritate the injection site.