Please check your internet connection and try again.
# Norepinephrine
## Overview
Norepinephrine is a potent catecholamine acting primarily on alpha-1 and beta-1 adrenergic receptors. It causes peripheral vasoconstriction (increasing systemic vascular resistance) and exerts positive inotropic effects with minimal chronotropic effect compared to epinephrine.
## Primary Indications
* First-line agent for distributive shock (septic, neurogenic).
* Hypotension refractory to fluid resuscitation.
* Cardiac arrest (less common, usually second-line).
## Adult Dosing
* **Initial:** 0.05 to 0.1 mcg/kg/min (or 2–4 mcg/min fixed dose) via continuous IV infusion.
* **Titration:** Titrate by 0.05–0.2 mcg/kg/min every 3–5 minutes to achieve target Mean Arterial Pressure (MAP), typically ≥ 65 mmHg.
* **Maintenance Range:** 0.01 to 3 mcg/kg/min.
* **Note:** Dosing varies significantly by institutional protocol.
## Pediatric Dosing
* **Initial:** 0.05 to 0.1 mcg/kg/min via continuous IV infusion.
* **Titration:** Titrate to effect; common range is 0.05–1 mcg/kg/min.
* **Note:** Must be administered via a dedicated central line whenever possible.
## Dose Adjustments
* **Renal/Hepatic:** No specific adjustments defined; however, observe for altered clearance in severe failure.
* **Tapering:** Must be tapered slowly to avoid rebound hypotension.
## Contraindications
* Hypersensitivity to norepinephrine or bisulfites.
* Mesenteric or peripheral vascular thrombosis (relative contraindication due to risk of ischemia).
* Hypotension secondary to uncorrected hypovolemia (volume resuscitation must be prioritized).
## Adverse Effects
* **Cardiovascular:** Hypertension, arrhythmias (tachycardia, bradycardia), myocardial ischemia.
* **Extravasation:** Severe tissue necrosis and sloughing (if leakage occurs).
* **Metabolic:** Hyperglycemia, metabolic acidosis (prolonged high-dose use).
* **Peripheral:** Digital ischemia and limb necrosis.
## Key Drug Interactions
* **MAO Inhibitors / TCAs:** May cause severe, prolonged hypertensive crisis.
* **Beta-blockers:** May cause unopposed alpha-adrenergic vasoconstriction, leading to extreme hypertension and reflex bradycardia.
* **Anesthetics (Halogenated):** May sensitize the myocardium to arrhythmias.
## Monitoring
* **Continuous:** Hemodynamic monitoring (MAP, pulse, EKG).
* **Site:** Check IV site hourly for infiltration/extravasation.
* **Perfusion:** Monitor urine output and serum lactate to assess end-organ perfusion.
* **Recommendation:** Central venous access is strongly preferred; peripheral administration should be reserved for urgent, short-term use in large veins with dilute concentrations.
## Clinical Pearls
* **Extravasation Management:** If extravasation occurs, discontinue infusion and infiltrate the site with **Phentolamine** (5–10 mg in 10 mL saline) locally to block alpha-receptors and prevent necrosis.
* **Stability:** Ensure compatibility with fluids (D5W or NS/D5W).
* **Concentration:** Always verify infusion concentrations against institutional standard kits to avoid bedside calculation errors.
***
*Disclaimer: This information is for educational purposes only. Clinical protocols vary by institution. Always verify dosages, contraindications, and drug compatibility through current institutional guidelines, electronic health records, or the official FDA-approved package insert before administration.*
