When a procedure is intravenous, it takes place “within a vein.” Typically, it is used in reference to fluids or medicine given through a tube or needle inserted in a vein.
For example, an IV line can supply fluids and other essential nutrients directly to the bloodstream for those who cannot eat or drink.
IV infusion can also be used to administer medicine, and by going right into the bloodstream, the therapeutic effect is greater. Drugs administered orally must go through the digestive system, which removes a significant portion of the medicine. However, intravenous therapy can bypass the digestive system and help the patient more quickly.