Intravenous Infusion
An intravenous infustion is a liquid administered directly into the bloodstream via a vein. The first polio vaccine in 1952 was injected intravenously until an oral vaccine replaced it in 1955.
When a rapid onset of action is needed, medications may be administered intravenously, intramuscularly, under the tongue (sublingual), or by intranasal or oral inhalation (insufflation).
