is the injection
of a substance directly into a muscle
. In medicine
, it is one of several alternative methods for the administration of medications
(see Route of administration
). It is used for particular forms of medication that are administered in small amounts. Depending on the chemical properties of the drug, the medication may either be absorbed fairly quickly or more gradually. Intramuscular injections are often given in the deltoid
, vastus lateralis
, ventrogluteal and dorsogluteal muscles.
Complications and contraindications
When the gluteal muscles
are used, injections should be made on the upper, outer quadrant of the buttock
to avoid damaging the sciatic nerve
. Injection fibrosis
is a complication that may occur if the injections are delivered with great frequency or with improper technique.
Thrombocytopenia (low platelet counts) and coagulopathy (bleeding tendency) are contraindications for intramuscular injections, as they may lead to hematomas.
Examples of medications that are sometimes administered intramuscularly are:
In addition, some vaccines are administered intramuscularly:
Also certain substances (i.e. ketamine) are injected intramuscularly for recreational purposes.