<unk>  is the<unk>  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.<unk> s are often given in the deltoid, vastus lateralis, ventrogluteal and dorsogluteal muscles. When the gluteal muscles are used,<unk> s should be made on the upper, outer quadrant of the buttock to avoid damaging the sciatic nerve.<unk>  fibrosis is a complication that may occur if the<unk> s are delivered with great frequency or with<unk> proper technique.
Thrombocytopenia (low platelet counts) and coagulopathy (bleeding tendency) are contraindications for<unk> s, as they may lead to hematomas.
Examples of medications that are sometimes administered<unk> ly are:
codeine
methotrexate
metoclopramide
olanzapine
Streptomycin
diazepam
prednisone
Interferon beta-1a
sex hormones, such as testosterone, estradiol valerate, and Depo Provera
dimercaprol
ketamine
naloxone
quinine in its gluconate form
In addition, some vaccines are administered<unk> ly:
Gardasil
hepatitis A vaccine
Also certain substances (i.e. ketamine) are injected<unk> ly for recreational purposes.
Intramuscular injection
Injection 
Intraosseous infusion
Nasal spray
Local anesthesia
Catheter
General anaesthetic
Inhalation