Editing Intramuscular injection (section)

{{Short description|Medical injection into a muscle}}
{{cs1 config|name-list-style=vanc}}
{{Good article}}
{{Infobox medical intervention
| Name        = Intramuscular injection
| Image       = Bracing for a short, sharp jab.jpg
| alt         =
| Caption     = A healthcare worker preparing to administer a vaccine via intramuscular injection
| MeshID      = D007273
| ICD9        = 99.1
| ICD10       = 3E023
| CPT         = 96372
}}

'''Intramuscular injection''', often abbreviated '''IM''', is the [[medical injection|injection]] of a substance into a [[muscle]]. In [[medicine]], it is one of several methods for [[parenteral|parenteral administration]] of medications. Intramuscular injection may be preferred because muscles have larger and more numerous [[blood vessel]]s than subcutaneous tissue, leading to faster absorption than [[subcutaneous injection|subcutaneous]] or [[intradermal injection]]s. Medication administered via intramuscular injection is not subject to the [[first-pass metabolism]] effect which affects oral medications.

Common sites for intramuscular injections include the [[deltoid muscle]] of the upper arm and the [[gluteal muscle]] of the buttock. In infants, the [[vastus lateralis muscle]] of the thigh is commonly used. The injection site must be cleaned before administering the injection, and the injection is then administered in a fast, darting motion to decrease the discomfort to the individual. The volume to be injected in the muscle is usually limited to 2–5 [[milliliter]]s, depending on injection site. A site with signs of infection or muscle atrophy should not be chosen. Intramuscular injections should not be used in people with [[myopathy|myopathies]] or those with trouble clotting.

Intramuscular injections commonly result in pain, redness, and swelling or [[inflammation]] around the injection site. These side effects are generally mild and last no more than a few days at most. Rarely, [[nerve]]s or blood vessels around the injection site can be damaged, resulting in severe pain or [[paralysis]]. If proper technique is not followed, intramuscular injections can result in localized infections such as [[abscess]]es and [[gangrene]]. While historically aspiration, or pulling back on the syringe before injection, was recommended to prevent inadvertent administration into a vein, it is no longer recommended for most injection sites by some countries.