Intravenous therapy (abbreviated as IV therapy) is a medical process that administers fluids, medications and nutrients directly into a person's vein. The intravenous route of administration is commonly used for rehydration or to provide nutrients for those who cannot, or will not—due to reduced mental states or otherwise—consume food or water by mouth. It may also be used to administer medications or other medical therapy such as blood products or electrolytes to correct electrolyte imbalances. Attempts at providing intravenous therapy have been recorded as early as the 1400s, but the practice did not become widespread until the 1900s after the development of techniques for safe, effective use.
The intravenous route is the fastest way to deliver medications and fluid replacement throughout the body as they are introduced directly into the circulatory system and thus quickly distributed. For this reason, the intravenous route of administration is also used for the consumption of some recreational drugs. Many therapies are administered as a "bolus" or one-time dose, but they may also be administered as an extended infusion or drip. The act of administering a therapy intravenously, or placing an intravenous line ("IV line") for later use, is a procedure which should only be performed by a skilled professional. The most basic intravenous access consists of a needle piercing the skin and entering a vein which is connected to a syringe or to external tubing. This is used to administer the desired therapy. In cases where a patient is likely to receive many such interventions in a short period (with consequent risk of trauma to the vein), normal practice is to insert a cannula which leaves one end in the vein, and subsequent therapies can be administered easily through tubing at the other end. In some cases, multiple medications or therapies are administered through the same IV line.
