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When a medication is injected directly into muscle, it is called an intramuscular injection (IM). The Z-track method is a type of IM injection technique used to prevent tracking (leakage) of the medication into the subcutaneous tissue (underneath the skin).
During the procedure, skin and tissue are pulled and held firmly while a long needle is inserted into the muscle. After the medication is injected, the skin and tissue are released. When you insert a needle into the tissues, it leaves a very small hole, or track. Small amounts of medication can sometimes leak backwards through this track and be absorbed into other tissues. Pulling the skin and tissue before the injection causes the needle track to take the shape of the letter "Z," which gives the procedure its name. This zigzag track line is what prevents medication from leaking from the muscle into surrounding tissue.
The procedure is usually administered by a nurse or doctor. In some cases, you may be instructed how to perform Z-track injections on yourself at home. You may also need the help of a caregiver, friend or family member to administer the injection.
Side effects can include swelling and injection discomfort. However, Z-track injection is usually less painful than a traditional IM injection.
The Z-track method is not often recommended, but can be particularly useful with medication that must be absorbed by muscle to work. It also helps to prevent medication from seeping into the subcutaneous tissue and ensures a full dosage. Some medications are dark colored and can cause staining of the skin. If this is a side effect of the medication you will be taking, the doctor may recommend using this technique to prevent injection site discoloration or lesions.
Z-track injections can be performed at any intramuscular injection location, though the thigh and buttocks are the most common sites.
It is important that the correct size needle is used. Your healthcare team will advise you on which needle and syringe to use, taking your weight, build, and age into consideration. You may also be asked about preexisting conditions. Be sure to tell your doctor if you have a bleeding disorder. In an adult, the most commonly used needles are one inch or one and a half inches long, and 22 to 25 gauge thick. Smaller needles are typically used when injecting a child.
Note: Never massage the site of your Z-track injection. This may cause the medication to leak. It may also cause irritation.
Z-track injection is generally considered a common and safe procedure. Mild side effects include swelling, site pain, and bruising. Less common, but more serious risks include:
If you notice any unusual side effects or signs of an infection, promptly notify your physician.
Written by: Ann Pietrangelo
Medically reviewed on: Oct 05, 2015: Nicole Galan, RN
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