Please check your internet connection and try again.
# Norepinephrine
## Overview
Norepinephrine is a potent vasopressor and inotrope that acts primarily on alpha-1 adrenergic receptors, causing vasoconstriction, and also on beta-1 adrenergic receptors, increasing heart rate and contractility.
## Primary Indications
* Severe hypotension and shock, including septic shock and cardiogenic shock, to maintain adequate organ perfusion.
## Adult Dosing
* **Initiation:** Typically started at 0.01 to 0.03 mcg/kg/min intravenously.
* **Titration:** May be titrated up to 0.1 mcg/kg/min, and in some cases up to 0.5 mcg/kg/min or higher, based on hemodynamic response (e.g., mean arterial pressure, heart rate).
* **Maximum Dose:** Higher doses may be used but are associated with increased risk of adverse effects. Dosing is highly individualized and guided by continuous hemodynamic monitoring and clinical response. Specific target parameters (e.g., MAP goal) are often determined by local protocols.
## Pediatric Dosing
* **Initiation:** 0.05 to 0.1 mcg/kg/min intravenously.
* **Titration:** May be titrated up to 2 mcg/kg/min based on clinical response. Dosing should be guided by institutional protocols and expert consultation.
## Dose Adjustments
* No specific dose adjustments are typically required for renal or hepatic impairment, as norepinephrine is metabolized in the liver and kidneys. However, extreme caution and close monitoring are warranted in patients with severe dysfunction.
## Contraindications
* Hypersensitivity to norepinephrine.
* Generally not recommended for use in patients with severe hypovolemia unless fluid resuscitation is initiated concurrently.
## Adverse Effects
* **Common:** Tachycardia, bradycardia (reflex), hypertension, peripheral vasoconstriction, decreased blood flow to extremities, skin necrosis (especially with extravasation), anxiety, headache, tremors, increased myocardial oxygen demand.
* **Serious:** Arrhythmias, myocardial infarction, limb ischemia, pulmonary edema.
## Key Drug Interactions
* **Monoamine Oxidase Inhibitors (MAOIs):** Potentiate hypertensive crisis. Norepinephrine should not be used in patients receiving MAOIs or within 14 days of discontinuing MAOIs.
* **Tricyclic Antidepressants (TCAs):** May potentiate the pressor response.
* **Beta-blockers:** May blunt the beta-1 effects of norepinephrine, leading to unopposed alpha-1 vasoconstriction.
* **Alpha-blockers:** May antagonize the alpha-1 effects of norepinephrine.
* **Anesthetics:** Some halogenated anesthetics can increase myocardial irritability and potentiate arrhythmias.
* **Ergot alkaloids, oxytocin:** May potentiate the pressor effect.
## Monitoring
* **Hemodynamics:** Continuous arterial blood pressure monitoring is essential. Heart rate, central venous pressure (CVP), and pulmonary artery catheterization data (if available) should be assessed.
* **Perfusion:** Monitor urine output, peripheral pulses, skin temperature and color, and mental status.
* **ECG:** For arrhythmias.
* **Infusion Site:** Closely monitor for signs of extravasation.
## Clinical Pearls
* Norepinephrine should 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.
* In patients with septic shock, norepinephrine is often the first-line vasopressor.
* The risk of arrhythmias and myocardial ischemia increases with higher doses and longer durations of therapy.
***
*This information is for educational purposes only and does not substitute for professional medical advice. Always consult the most current prescribing information and guidelines before making any clinical decisions.*
