Intramuscular injection is an injection of a substance directly into a muscle. In medicine, It is one of several alternative methods for the administration of medicines (see: route of administration) It is used for particular forms of medication which are administered in small amounts. Depending on the chemical properties of the drug, the medication may either be absorbed fairly quickly or more gradually.

Some medications administered intramuscularly:

• metoclopramide
• codeine
• goserelin
• many vaccines