Please check your internet connection and try again.
# Norepinephrine
## Overview
A potent catecholamine acting primarily on alpha-1 adrenergic receptors (vasoconstriction) and, to a lesser extent, beta-1 adrenergic receptors (inotropy). It is the preferred first-line vasopressor for septic shock.
## Primary Indications
* Acute hypotensive states (e.g., septic, cardiogenic, or neurogenic shock) after adequate fluid resuscitation.
* Adjunct in cardiac arrest (less common).
## Adult Dosing
* **Initial Infusion:** 0.01–0.05 mcg/kg/min (or 2–4 mcg/min fixed-rate).
* **Titration:** Increase by 0.05–0.1 mcg/kg/min every 3–5 minutes until the target mean arterial pressure (MAP) is achieved.
* **Maintenance:** Usual range 0.01–0.5 mcg/kg/min.
* **Max Dose:** Generally no specific cap, but high doses (>1 mcg/kg/min) are associated with severe peripheral ischemia and refractory shock. Local ICU protocols vary widely regarding maximum titration.
## Pediatric Dosing
* **Initial Infusion:** 0.05–0.1 mcg/kg/min.
* **Titration:** Titrate to effect in increments of 0.05–0.1 mcg/kg/min.
* **Max Dose:** Up to 1–2 mcg/kg/min; consult institutional guidelines as pediatric intensive care protocols differ by facility.
## Dose Adjustments
* **Renal/Hepatic Impairment:** No formal dosage adjustments provided; however, use caution as sensitivity may vary in patients with chronic organ dysfunction.
## Contraindications
* Hypersensitivity to norepinephrine or sulfites.
* Hypotension due to uncorrected blood volume deficit (except as an emergency measure before/during fluid replacement).
* Thrombosis (mesenteric or peripheral vascular) - generally avoided due to profound vasoconstriction.
## Adverse Effects
* **Cardiovascular:** Tachycardia, arrhythmias (atrial/ventricular), hypertension, bradycardia (reflex).
* **Peripheral:** Digital/limb ischemia, skin necrosis (if extravasation occurs).
* **Metabolic:** Hyperglycemia, lactic acidosis (at prolonged high doses due to localized hypoperfusion).
## Key Drug Interactions
* **MAO Inhibitors / TCAs:** May produce severe, prolonged hypertension; dose reduction of norepinephrine is required.
* **Beta-blockers:** May result in unopposed alpha-adrenergic stimulation (severe hypertension and reflex bradycardia).
* **Halogenated Hydrocarbons (e.g., volatile anesthetics):** May sensitize the myocardium to arrhythmias.
## Monitoring
* **Hemodynamics:** Continuous intra-arterial blood pressure monitoring (ABP) is strongly recommended for titrating and preventing extravasation.
* **Perfusion:** Monitor peripheral pulses, capillary refill, and skin integrity at the site of infusion.
* **Labs:** Serum lactate, electrolytes, and renal function.
* **Site:** Always prioritize use via central venous catheter (CVC) to minimize risk of tissue necrosis. If peripheral administration is necessary, use a large-bore proximal vein for the shortest duration possible.
## Clinical Pearls
* **Extravasation Management:** If extravasation occurs, discontinue infusion and infiltrate the area with phentolamine (5–10 mg in 10 mL saline) locally to prevent necrosis.
* **Compatibility:** Highly acidic; essentially incompatible with most alkaline drugs (e.g., NaHCO3). Refer to institutional compatibility charts before Y-site administration.
* **Weaning:** When weaning, prioritize the restoration of organ perfusion over absolute MAP goals to avoid early recurrence of shock.
***
*Disclaimer: This information is for educational purposes and reflects general clinical practice. Always consult your institution's specific clinical protocols and the most recent package insert before prescribing or administering medication.*
