Norepinephrine is similar to adrenaline. It works by constricting (narrowing) the blood vessels and increasing blood pressure and blood glucose (sugar) levels. Norepinephrine is used to treat life-threatening low blood pressure (hypotension) that can occur with certain medical conditions or surgical procedures. This medication is often used during CPR (cardio-pulmonary resuscitation). Norepinephrine may also be used for purposes not listed in this medication guide.