Norepinephrine is also known as noradrenaline and it belongs to a drug class known as catecholamines. Norepinephrine is a hormone that is found in human beings and animals. Norepinephrine is also a neurotransmitter that is responsible for vigilant concentration. Norepinephrine works the same way as adrenaline, where it narrows or constricts the blood vessels causing hypertension and increases the blood sugar levels. Norepinephrine can be used to treat hypotension.