A Beginner’s Guide to Norepinephrine (Levophed)

It took me about 2 hours into my orientation in ICU to be introduced to this medication and I don’t think I’ve had a shift in ICU where I wasn’t using it in some capacity. So, I’d say it’s a pretty important medication to know about as an ICU nurse. I had heard the name in my time in OR from anesthesia, but never needed to know about it in detail.

Indication for Norepinephrine (Levophed)

The main indication for norepinephrine is hypotension. Specifically, severe acute hypotension. This is a medication used in the hospital setting, most often in the intensive care setting. This medication can be started in the emergency department, but as soon as this med hits the patient they are calling for a transfer to ICU. Hypotension due to hypovolemia is not an indication for norepinephrine, the first goal in this scenario is fluid replacement. An off-label use for norepinephrine is the treatment of hepatorenal syndrome (HRS).

Norepinephrine (Levophed) Mechanism of Action

Norepinephrine is chemically similar to epinephrine, the only difference is one methyl group. It acts as an agonist against alpha1 and beta1 receptors. Activation of alpha1 receptors leads to vasoconstriction and an increase in systemic vascular resistance. Low doses of norepinephrine can increase cardiac output.

What is vasoconstriction?

Vasoconstriction is when blood vessels are narrowed due to contraction of the smooth muscle layer in the lining of the vasculature. This contraction creates a smaller diameter for the blood vessel which leads to an increased resistance to bloodflow. Due to the increased resistance, the heart pumps harder to force the blood through the vessels. All of this happens to increase blood pressure. Norepinephrine is also a cardiac stimulant and dilates coronary arteries.

Pharmacokinetics

Norepinephrine has a rapid onset of action. It takes about 5 minutes after initiation for effects to be apparent. It has a short halflife of 2.5 minutes. Due to the short half life an continuous infusion is needed versus an IV push.

What You Need to Know About Norepinephrine (Levophed)

Ideally, norepinephrine should be administered through a central line as it is an irritant medication. Administering norepinephrine through a peripheral line, especially at higher doses, increases the risk of tissue damage due to extravasation.

Typically norepinephrine is formulated in regular and quad strength. Ensure you are administered the correct dose!

MAP Goal

Know your MAP goal. Most of the time it will be a goal of 65 or greater, however sometimes this gets altered based on the patient and everything they have going on during their admission.

Assessment

Pay close attention to the skin around the administration site, especially if it’s peripherally running. But, due to the vasoconstriction blood flow may be reduced peripherally, so play close attention to the fingers, toes, heels, etc. Ensure you are protected against pressure injuries. If you notice signs of decreased blood flow to any area, alert the intensitivist right away for intervention.

Side Effects and Toxicity

The most common side effects from norepinephrine are a headahce and dizziness. Depending on your patient’s status, they may or may not be able to even report these symptoms. When I think of this side effect, it makes me think of orthostatic hypotension because of the shift in blood.

Toxicity of norepinephrine presents as an intence headache, hypertensive urgency, increased peripheral vascular resistance (PVR), reduced cardiac output (CO). If toxicity is suspected, you will likely be stopping the infusion. The doctor may order Phentolamine as a treatment for toxicity.