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# Norepinephrine
## Overview
Norepinephrine is a potent catecholamine acting primarily on alpha-1 adrenergic receptors (vasoconstriction) and, to a lesser extent, beta-1 adrenergic receptors (inotropic effect). It is the first-line vasopressor for septic shock.
## Primary Indications
* Acute hypotensive states (e.g., septic shock, cardiogenic shock).
* Adjunct in cardiac arrest (less common).
## Adult Dosing
* **Initial:** 0.01–0.05 mcg/kg/min via continuous IV infusion.
* **Titration:** Titrate every 3–5 minutes to achieve target mean arterial pressure (MAP) (usually ≥65 mmHg).
* **Typical Dose:** 0.05–0.5 mcg/kg/min; refractory cases may require >1 mcg/kg/min.
* *Note: Dosing is highly dependent on institutional protocols and stability.*
## Pediatric Dosing
* **Initial:** 0.05–0.1 mcg/kg/min via continuous IV infusion.
* **Titration:** Titrate to clinical effect (e.g., perfusion, blood pressure).
* **Max:** Generally considered 1–2 mcg/kg/min; use caution with higher rates due to risk of end-organ ischemia.
## Dose Adjustments
* **Renal/Hepatic:** No specific dosage adjustments established, but use caution; monitor for end-organ perfusion.
* **Tapering:** Must be tapered slowly to prevent rebound hypotension.
## Contraindications
* Hypersensitivity to norepinephrine or sulfites.
* Avoid in patients with profound mesenteric or peripheral vascular thrombosis.
## Adverse Effects
* **Common:** Bradycardia (reflex), hypertension, arrhythmias.
* **Serious:** Tissue necrosis/extravasation (if leakage occurs), limb ischemia, mesenteric ischemia.
## Key Drug Interactions
* **MAOIs/Tricyclic Antidepressants:** May cause severe, prolonged hypertension.
* **Beta-blockers:** May result in unopposed alpha-adrenergic activity (excessive vasoconstriction).
## Monitoring
* **Hemodynamics:** Continuous blood pressure (arterial line preferred) and heart rate monitoring.
* **Site Assessment:** Must be infused via a central line ideally; inspect IV site frequently for signs of extravasation.
* **Perfusion:** Monitor urine output, lactate, and peripheral perfusion (to assess for ischemia).
## Clinical Pearls
* **Extravasation Management:** If extravasation occurs, stop the infusion immediately and consider local infiltration with **phentolamine** (adrenergic antagonist) to prevent necrosis.
* **Compatibility:** Highly acidic; check compatibility before Y-site administration.
* **Fluid Status:** Ensure adequate volume resuscitation prior to or concurrent with initiation, as vasopressors are ineffective in profound hypovolemia.
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**Disclaimer:** This information is for educational purposes only. Clinical practice and institutional guidelines vary widely. Always consult current institutional protocols and the official manufacturer prescribing information before administering medications.
