Intravenous is a term that means within the vein. An injection is something that is introduced into something else. An intravenous injection is the introduction of a substance into the veins using a needle. This may be necessary for medical reasons. It may also be done for illicit purposes.
An injection can involve one or more single doses of a substance administered through a needle. The substance to be administered is usually stored in a syringe, which is attached to the needle. Once the needle is inserted into a vein, the raised portion of the syringe may be depressed, forcing the substance into the vein.
Giving an injection intravenously can be a means of therapy in some other medical cases. Sometimes, such as in cases of dehydration, a person is given fluids intravenously over an extended period, which could be hours or days. Instead of syringes, the substance to be injected is often stored in bags hung above the patient. The substance flows through tubes to the needle. Gravity is the force that is generally used to make this possible. The flow is generally controlled by clips that can be connected to the tube that runs to the needle.
Doing this is a means to quickly replace fluids the body needs. This method of treatment may be referred to as a drip or an IV. Blood transfusions and intravenous feeding may also be administered in this way.
There are complications that may occur during an intravenous injection. An air embolism is one of them. This happens when a large quantity of air enters the blood stream. This can affect blood flow. Infiltration can occur if the needle pierces the wall of a vein. In this case, the injected substance may begin to gather in the spaces around the vein. Such complications should be dealt with immediately.
Sometimes intravenous injection occurs outside of the medical setting. This is often true among users of illicit drugs such as heroin or amphetamines. Consuming drugs this way can produce an instant high. This is because the illicit substance is introduced directly into the blood stream. Other methods of drug consumption may be slower because the substance has to travel.
Intravenous injection of illicit substances can often lead to more problems than addiction. A mild effect may be scarring which results from the repeat piercing of an area. These scars are often referred to as tracks. A vein can also be damaged in a way that interrupts proper blood flow. Furthermore, many users who share needles contract serious illnesses such as hepatitis and AIDS.