<P> Drug injection is a method of introducing a drug into the bloodstream via a hollow hypodermic needle and a syringe, which is pierced through the skin into the body (usually intravenous, but also intramuscular or subcutaneous). It often applies to substance dependence and recreational drug use . Typically, the powdered drug is mixed with water to create a solution, and then the solution is injected . This act is often colloquially referred to as "slamming", "shooting (up)", "banging", "pinning", or "jacking - up", often depending on the specific drug subculture in which the term is used (i.e. heroin, cocaine, or methamphetamine). </P> <P> Although there are various methods of taking drugs, injection is favoured by some users as the full effects of the drug are experienced very quickly, typically in five to ten seconds . It also bypasses first - pass metabolism in the liver, resulting in higher bioavailability and efficiency for many drugs (such as morphine or diacetylmorphine / heroin; roughly two - thirds of which is destroyed in the liver when consumed orally) than oral ingestion would, meaning users get a stronger (yet shorter - acting) effect from the same amount of the drug . This shorter, more intense "high" can lead to a dependency--both physical and psychological--developing more quickly than with other methods of taking drugs . As of 2004, there were 13.2 million people worldwide who used injection drugs, of which 22% are from developed countries . </P>

The injection of a drug with a needle is called