<P> Female - to - male transgender people may use hypodermic needles for self - injection of prescription testosterone . Male - to - female transgender people may also use hypodermic needles for self - injection of estrogen . This is not prevalent enough in the community for this to pose a severe risk of HIV or other infection transmissions . </P> <P> Hypodermic needles are also used by untrained users in recreational intravenous drug use (e.g., injecting solutions of heroin and water). Before governments attained current levels of awareness about the spread of disease through shared needles, hypodermic syringes in many countries were available only by prescription . Thus in order to limit the spread of blood - borne diseases such as hepatitis and HIV through shared injection equipment, many countries have needle exchange programs in most larger cities . In some countries, such programs are wholly or partially subsidized by the government . Blunted needles, manufactured without a sharp bevel and usually non-sterile, are used industrially for filling small containers or accurately applying small amounts of solvent or glue . </P> <P> It is estimated that about 10% of the adult population may have a phobia of needles (trypanophobia), and it is much more common in children, ages 5--17 . Patients can ask for a patch from the nurse to numb the area of where the injection will take place to reduce pain . </P>

Where does a hypodermic needle deliver its contents