Please check your internet connection and try again.
# Norepinephrine
## Overview
Norepinephrine is a sympathomimetic amine that acts as a vasopressor and cardiac stimulant. It primarily stimulates alpha-1 adrenergic receptors, causing vasoconstriction and increasing systemic vascular resistance and blood pressure. It also has some beta-1 adrenergic receptor activity, leading to increased cardiac contractility and heart rate.
## Primary Indications
* Management of severe hypotension and shock (e.g., septic shock, cardiogenic shock) refractory to fluid resuscitation.
## Adult Dosing
* **Initial dose:** 4 to 12 mcg/minute intravenously.
* **Titration:** Titrate infusion rate to achieve target mean arterial pressure (MAP) of 65 mmHg or higher, or as per local protocol. Doses may range from 2 to 30 mcg/minute.
* **Maximum dose:** There is no absolute maximum dose; however, doses exceeding 30 mcg/minute are rarely needed and require careful consideration of risks and benefits.
## Pediatric Dosing
* **Initial dose:** 0.05 to 0.2 mcg/kg/minute intravenously.
* **Titration:** Titrate infusion rate to achieve target systolic blood pressure of 70 mmHg (age 0-1 year) or 90 mmHg (age 1-10 years), or as per local protocol. Doses may range from 0.05 to 1 mcg/kg/minute.
## Dose Adjustments
* No dose adjustment is typically required for hepatic or renal impairment, as norepinephrine is metabolized in the liver and kidneys and cleared renally. However, careful monitoring is essential in patients with compromised organ function.
## Contraindications
* Hypersensitivity to norepinephrine.
* Use as the sole agent to manage hypotension due to hypovolemia (requires adequate fluid resuscitation first).
* Severe distributive shock with profound hypoperfusion where aggressive vasoconstriction may be detrimental.
## Adverse Effects
* **Cardiovascular:** Hypertension, reflex bradycardia, arrhythmias, peripheral ischemia, extravasation leading to tissue necrosis.
* **Other:** Headache, anxiety, tremor, dyspnea.
## Key Drug Interactions
* **MAO inhibitors and tricyclic antidepressants:** May prolong and intensify the pressor effect of norepinephrine. Separate administration by at least 14 days.
* **Beta-blockers:** May blunt the desired pressor effect and lead to unopposed alpha-stimulation, potentially causing severe hypertension.
* **Alpha-blockers:** May antagonize the pressor effect.
* **Oxytocics:** May potentiate the pressor effect of norepinephrine.
## Monitoring
* Continuous electrocardiogram (ECG).
* Arterial blood pressure (invasive monitoring is preferred).
* Central venous pressure (CVP) and/or pulmonary artery catheter (PAC) if available.
* Urine output.
* Peripheral circulation (e.g., skin temperature, color, capillary refill).
* Infusion site 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 administer phentolamine mesylate infiltrated locally into the affected area.
* Norepinephrine is light-sensitive; protect the infusion from light.
* It is incompatible with alkaline solutions.
***
*Disclaimer: This information is intended for healthcare professionals. Always consult the current prescribing information and institutional guidelines for definitive dosing and management.*
