Please check your internet connection and try again.
# Norepinephrine (Levophed)
## Overview
Norepinephrine is a potent sympathomimetic amine that acts primarily as an alpha-adrenergic agonist, causing vasoconstriction and increasing peripheral vascular resistance. It also has beta-1 adrenergic effects, increasing cardiac output.
## Primary Indications
* Severe hypotension and shock (e.g., septic shock, cardiogenic shock, neurogenic shock).
* Cardiac arrest (as an alternative to epinephrine in certain advanced cardiac life support protocols).
## Adult Dosing
* **Hypotension/Shock:** Typically initiated at 0.01 to 0.02 mcg/kg/min via continuous intravenous infusion.
* **Titration:** The dose is titrated to maintain a target mean arterial pressure (MAP) of 65 mmHg or higher, or as per local protocol. Doses can be increased up to 0.1 mcg/kg/min, and in rare cases, up to 2 mcg/kg/min or higher if necessary.
* **Cardiac Arrest:** Dosing and administration often follow advanced cardiac life support (ACLS) guidelines and may be administered as a bolus dose, though continuous infusion is more common for shock. Specific protocols vary.
## Pediatric Dosing
* **Hypotension/Shock:** 0.05 to 0.1 mcg/kg/min via continuous intravenous infusion.
* **Titration:** Titrated to support blood pressure. Doses may be increased up to 1 mcg/kg/min.
## Dose Adjustments
* **Renal Impairment:** No specific dose adjustment is typically recommended, but close monitoring of hemodynamic response is crucial.
* **Hepatic Impairment:** No specific dose adjustment is typically recommended, but close monitoring of hemodynamic response is crucial.
## Contraindications
* Hypersensitivity to norepinephrine.
* Hypotension resulting from volume deficits before fluid resuscitation.
* Patients receiving or having recently received monoamine oxidase (MAO) inhibitors (risk of hypertensive crisis).
## Adverse Effects
* **Cardiovascular:** Arrhythmias (especially ventricular), bradycardia, hypertension, peripheral ischemia, extravasation leading to tissue necrosis.
* **Central Nervous System:** Headache, anxiety, tremor, dizziness.
* **Respiratory:** Dyspnea.
* **Other:** Nausea, vomiting, sweating.
## Key Drug Interactions
* **MAO Inhibitors:** Concomitant use can lead to severe hypertension. Discontinue MAO inhibitors at least 14 days prior to norepinephrine administration.
* **Tricyclic Antidepressants (TCAs) and Cocaine:** May potentiate the pressor effects of norepinephrine.
* **Beta-Adrenergic Blockers:** May blunt the cardiac effects of norepinephrine or lead to unopposed alpha-adrenergic stimulation.
* **Alpha-Adrenergic Blockers:** May antagonize the vasoconstrictive effects of norepinephrine.
* **General Anesthetics:** Some can increase myocardial irritability and susceptibility to arrhythmias.
## Monitoring
* **Hemodynamic Parameters:** Continuous electrocardiogram (ECG), heart rate, blood pressure (MAP), central venous pressure (CVP), pulmonary artery pressures (if available), cardiac output (if available).
* **Urine Output:** To assess renal perfusion.
* **Infusion Site:** For signs of extravasation.
* **Mental Status:** To assess cerebral perfusion.
## Clinical Pearls
* Norepinephrine should *always* be administered via a central venous catheter to minimize the risk of extravasation and tissue necrosis.
* If extravasation occurs, discontinue the infusion immediately and infiltrate the affected area with phentolamine mesylate.
* Adequate fluid volume resuscitation is essential *before* initiating norepinephrine for hypotension due to hypovolemia.
* The infusion rate should be adjusted to achieve the desired hemodynamic endpoint rather than relying solely on a fixed dose.
* Gradually taper the infusion to avoid sudden drops in blood pressure.
***
**Disclaimer:** This information is for educational purposes only and does not constitute medical advice. Always consult the current prescribing information and relevant clinical guidelines for definitive patient care decisions.
