Please check your internet connection and try again.
# Norepinephrine
## Overview
Norepinephrine is a potent vasopressor and inotropic agent that acts primarily on alpha-1 adrenergic receptors, causing vasoconstriction, and to a lesser extent on beta-1 adrenergic receptors, increasing heart rate and contractility.
## Primary Indications
* Severe hypotension and shock (e.g., septic shock, cardiogenic shock) refractory to initial fluid resuscitation.
## Adult Dosing
* **Initial Rate:** Typically initiated at 0.01 to 0.05 mcg/kg/min IV infusion.
* **Titration:** May be titrated upward in increments of 0.01 to 0.05 mcg/kg/min every 5-15 minutes to achieve and maintain the target mean arterial pressure (MAP).
* **Maximum Dose:** Doses can be escalated up to 0.5 mcg/kg/min or higher, depending on clinical response and institutional protocols. Target MAP is often 65 mmHg or higher, but may be individualized.
## Pediatric Dosing
* **Initial Rate:** 0.05 to 0.1 mcg/kg/min IV infusion.
* **Titration:** May be titrated upward in increments of 0.05 to 0.1 mcg/kg/min every 10-15 minutes.
* **Maximum Dose:** Doses can be escalated up to 2 mcg/kg/min or higher, depending on clinical response and institutional protocols. Target MAP is often 40-50 mmHg, but may be individualized. Dosing regimens may vary significantly by institution.
## Dose Adjustments
No specific dose adjustments for renal or hepatic impairment are established. Use with caution and titrate carefully.
## Contraindications
* Hypersensitivity to norepinephrine.
* Concurrent use with certain anesthetics (e.g., cyclopropane, halothane) due to potential for severe arrhythmias.
## Adverse Effects
* **Cardiovascular:** Hypertension, bradycardia (reflex), tachycardia, arrhythmias, peripheral ischemia, necrosis (extravasation), palpitations.
* **Other:** Anxiety, headache, dizziness, tremor, dyspnea, nausea.
## Key Drug Interactions
* **MAO Inhibitors (MAOIs) and other sympathomimetics:** Potentiate pressor effects, potentially leading to hypertensive crisis. Discontinue MAOIs at least 14 days prior to norepinephrine initiation.
* **Beta-adrenergic blockers:** Can blunt the beta-1 effects of norepinephrine.
* **Alpha-adrenergic blockers:** Can antagonize the alpha-1 effects of norepinephrine.
* **Anesthetics:** Volatile anesthetics can increase myocardial irritability and risk of arrhythmias.
* **Ergot alkaloids, oxytocin:** May cause severe hypertension.
* **Tricyclic antidepressants (TCAs) and atomoxetine:** May potentiate the pressor response.
## Monitoring
* **Hemodynamic Parameters:** Continuous ECG monitoring, frequent blood pressure monitoring (arterial line preferred for continuous infusions), central venous pressure (CVP), pulmonary artery pressures (if available).
* **Perfusion:** Urine output, mental status, capillary refill, skin temperature and color.
* **Infusion Site:** Monitor closely for signs of extravasation (e.g., blanching, coolness, swelling).
## Clinical Pearls
* Norepinephrine is typically reconstituted and diluted further in a compatible IV solution (e.g., D5W or NS) prior to infusion. Specific dilution varies by institution.
* Administer via a central venous catheter to minimize the risk of extravasation.
* If extravasation occurs, discontinue the infusion immediately and infiltrate the affected area with phentolamine.
* Norepinephrine has a short half-life, so continuous infusion is necessary for sustained effect. Gradual tapering is recommended to avoid abrupt hypotension.
***
*This information is intended for healthcare professionals. Please consult the most current prescribing information and institutional protocols for definitive guidance.*
