Please check your internet connection and try again.
# Norepinephrine
## Overview
Norepinephrine is a potent catecholamine with primary alpha-1 agonist activity (vasoconstriction) and moderate beta-1 agonist activity (inotropic effect). It serves as a first-line vasopressor for distributive shock.
## Primary Indications
* Hypotension or refractory shock (septic, cardiogenic, or distributive).
* Cardiac arrest (as an adjunct).
## Adult Dosing
* **Initial Infusion:** 0.01 to 0.05 mcg/kg/min or 2 to 4 mcg/min (titrated to desired mean arterial pressure).
* **Titration:** Adjust by 0.01–0.05 mcg/kg/min or 1–2 mcg/min every 3–5 minutes based on hemodynamic response.
* **Typical Dose Range:** 0.01 to 3 mcg/kg/min.
* **Maximum Dose:** No formal established maximum, but clinical practice often relies on secondary pressor agents (e.g., vasopressin) before escalating to prohibitive dosages.
## Pediatric Dosing
* **Initial Infusion:** 0.05 to 0.1 mcg/kg/min.
* **Titration:** Titrate by 0.05 mcg/kg/min increments based on hemodynamics.
* **Typical Dose Range:** 0.05 to 2 mcg/kg/min.
* **Note:** Always verify pediatric protocols with institutional standards/PALS guidelines.
## Dose Adjustments
* **Renal/Hepatic:** No standardized adjustments required; consider underlying pathology when assessing hemodynamic response.
* **Dosing Dependency:** All dosing is highly dependent on institutional protocols; utilize infusion pumps and concentrated solution labels as defined by local policy.
## Contraindications
* Hypersensitivity to norepinephrine.
* Hypotension due to uncorrected blood volume deficit (except as an emergency measure before fluid replacement).
* Mesenteric or peripheral vascular thrombosis (relative contraindication).
## Adverse Effects
* **Cardiovascular:** Hypertension, arrhythmias (tachycardia/bradycardia), ischemia.
* **Local:** Extravasation can lead to severe tissue necrosis and sloughing (if leakage occurs, infiltrate area with phentolamine).
* **Other:** Anxiety, headache, respiratory difficulty.
## Key Drug Interactions
* **MAO Inhibitors/TCA:** May cause severe, prolonged hypertension.
* **Beta-blockers:** May lead to excessive alpha-receptor stimulation (unchecked vasoconstriction).
* **Cyclopropane/Halogenated Hydrocarbon Anesthetics:** Increase cardiac sensitivity to catecholamines, risking severe arrhythmias.
## Monitoring
* **Hemodynamics:** Continuous blood pressure (preferably arterial line), heart rate, and rhythm (ECG).
* **Perfusion:** Urine output, capillary refill, mental status, and lactate levels.
* **Site:** Strict assessment of IV access site for signs of extravasation.
## Clinical Pearls
* **Fluid First:** Ensure adequate volume resuscitation prior to or concurrently with vasopressor initiation; norepinephrine is not a substitute for hypovolemia correction.
* **Access:** Central venous access is preferred to minimize extravasation risk. In emergencies, peripheral administration is permissible via a large-bore proximal vein for short durations, but monitor site meticulously.
* **Weaning:** Taper slowly to avoid sudden recurrence of hypotension.
***
**Disclaimer**: This information is for educational purposes only. Always verify current prescribing information, institutional protocols, and safety guidelines through hospital-approved resources or current drug formularies before administration.
