Known brand names include Levophed.
A vasopressor given as a slow, continuous IV drip in the hospital to raise dangerously low blood pressure in adults. It tightens blood vessels and strengthens the heartbeat, and if it leaks out of the vein it can kill the nearby tissue.
Norepinephrine is an adrenergic drug, meaning it acts on the same receptors as the body's own adrenaline-type signals. On alpha receptors in blood vessel walls, it makes the vessels tighten and narrow, which raises blood pressure. On beta receptors in the heart, it makes each beat more forceful, and it widens the heart's own arteries so they carry more blood. The higher pressure sets off a reflex that slows the heart rate a little, so the heart usually pumps about the same amount of blood as before.
Blood pressure starts rising soon after the drip begins and levels off within about 5 minutes. The body clears it within minutes, so its effect fades within 1 to 2 minutes if the drip stops, which is why it is turned down gradually instead of stopped all at once. Because it narrows blood vessels, it can cut blood flow to the gut, kidneys, muscles, and limbs, and if it leaks out of the vein it can damage the skin and tissue around the site. It also raises calcium inside heart cells, which can set off abnormal heart rhythms.
Norepinephrine raises blood pressure in adults when it has fallen suddenly to a dangerously low level. When pressure drops that far, too little blood reaches the vital organs. The goal is to bring pressure back up to a low-normal range that keeps blood flowing to those organs.
It is used only in the hospital, where a healthcare provider mixes it into IV fluid and drips it slowly into a large vein. The amount is raised or lowered based on how the person's blood pressure responds. Low blood volume should be corrected before it is started, because squeezing the blood vessels of someone short on fluid can starve organs of blood even when the pressure reading looks normal. Its safety and effectiveness in children have not been established.
Headache and anxiety are the effects people are most likely to notice, while high blood pressure and a slow heartbeat are the reactions the label lists as most common. Trouble breathing can also occur. The label treats loss of blood flow to tissue as serious: the drug can starve the limbs and organs of blood, and a leak at the IV site can kill the surrounding skin. Stopping it suddenly can make blood pressure crash, it can trigger abnormal heart rhythms, and the sulfite it contains can cause allergic reactions, including asthma attacks, in sensitive people.