Please check your internet connection and try again.
# Norepinephrine
## Overview
Norepinephrine is a vasopressor and inotropic agent. It acts primarily on alpha-1 adrenergic receptors, causing peripheral vasoconstriction, and to a lesser extent on beta-1 adrenergic receptors, increasing myocardial contractility.
## Primary Indications
* Severe hypotension (shock) unresponsive to adequate fluid resuscitation.
* Cardiogenic shock.
* Septic shock.
## Adult Dosing
* **Typical Starting Dose:** 0.01 to 0.03 mcg/kg/min IV infusion.
* **Titration:** Increase dose by 0.01 to 0.03 mcg/kg/min every 5-15 minutes as needed to achieve target MAP (typically >65 mmHg).
* **Maximum Dose:** Generally considered to be 1 to 2 mcg/kg/min, though higher doses may be used in refractory shock under expert guidance. Specific maximums can vary based on institutional protocols.
## Pediatric Dosing
* **Typical Starting Dose:** 0.05 to 0.1 mcg/kg/min IV infusion.
* **Titration:** Increase dose by 0.05 to 0.1 mcg/kg/min every 5-15 minutes as needed.
* **Maximum Dose:** Up to 1 mcg/kg/min or higher, depending on clinical response and institutional protocol.
## Dose Adjustments
* **Renal Impairment:** No specific dose adjustment is typically recommended, but prolonged use may require careful monitoring.
* **Hepatic Impairment:** No specific dose adjustment is typically recommended, but prolonged use may require careful monitoring.
## Contraindications
* Hypersensitivity to norepinephrine.
* Use during cyclopropane and halogenated hydrocarbon anesthesia (risk of severe hypertension and arrhythmias).
## Adverse Effects
* **Cardiovascular:** Hypertension, reflex bradycardia, arrhythmias, peripheral ischemia, extravasation with tissue necrosis.
* **Neurologic:** Headache, anxiety.
* **Other:** Dyspnea.
## Key Drug Interactions
* **Monoamine Oxidase Inhibitors (MAOIs) & Tricyclic Antidepressants (TCAs):** Potentiate hypertensive effects; discontinue MAOIs/TCAs at least 10-14 days prior to norepinephrine use.
* **General Anesthetics:** Increased risk of arrhythmias and hypertension.
* **Beta-Blockers:** May unopposed alpha-adrenergic effects, leading to severe hypertension.
* **Alpha-Blockers:** May decrease pressor effect.
* **Ergot Alkaloids:** Potentiated vasoconstrictive effects.
## Monitoring
* **Hemodynamics:** Continuous ECG and blood pressure monitoring. Invasive arterial pressure monitoring is recommended for precise titration.
* **Infusion Site:** Frequent checks for signs of extravasation.
* **Urine Output:** Monitor for adequate perfusion.
* **Lactate:** Assess tissue perfusion.
## Clinical Pearls
* Always dilute before administration. Common concentrations are 16 mcg/mL (4 mg in 250 mL D5W or NS) or 32 mcg/mL (8 mg in 250 mL D5W or NS).
* Administer via a central venous catheter if possible to minimize risk of peripheral vasoconstriction and extravasation.
* If extravasation occurs, stop the infusion, aspirate any residual drug, and administer phentolamine intradermally into the affected area.
* Norepinephrine is light-sensitive; protect infusions from light.
***
*Disclaimer: This information is intended for healthcare professionals and is not a substitute for professional medical advice. Always consult the most current prescribing information and relevant institutional protocols before administering any medication.*
