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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 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 the treatment of cardiac arrest (rarely used).
## Adult Dosing
* **Initial:** 0.05–0.1 mcg/kg/min via continuous IV infusion.
* **Titration:** Titrate to target mean arterial pressure (MAP) ≥65 mmHg.
* **Typical effective range:** 0.01–3 mcg/kg/min.
* **Maximum:** No strict maximum; however, doses >1–2 mcg/kg/min indicate severe refractory shock and require consideration of vasopressin or hydrocortisone.
## Pediatric Dosing
* **Initial:** 0.05–0.1 mcg/kg/min via continuous IV infusion.
* **Titration:** Titrate by 0.05–0.1 mcg/kg/min every 5–15 minutes based on hemodynamic response.
* **Maximum:** Up to 1–2 mcg/kg/min.
* *Note: Always verify with local pediatric emergency protocols; weight-based dosing is critical.*
## Dose Adjustments
* **Renal/Hepatic:** No specific dose adjustments required; however, patients with organ failure may demonstrate increased sensitivity.
## Contraindications
* Hypersensitivity to norepinephrine or bisulfites.
* Hypotension due to uncorrected blood volume depletion (must restore intravascular volume first).
## Adverse Effects
* **Cardiovascular:** Hypertension, arrhythmias (tachycardia, bradycardia), myocardial ischemia.
* **Local:** Extravasation necrosis (use a central line whenever possible).
* **Systemic:** Peripheral ischemia/gangrene (digits, mesenteric).
## Key Drug Interactions
* **MAO Inhibitors/TCAs:** May cause severe, prolonged hypertension.
* **Alpha/Beta Blockers:** May antagonize the pressor effects of norepinephrine or lead to unopposed alpha-stimulation if beta-blockers are used without alpha-blockade.
* **Linezolid:** May potentiate vasopressor effects.
## Monitoring
* **Continuous arterial pressure monitoring:** Strongly recommended.
* **HR and ECG:** Monitor for arrhythmias.
* **Perfusion markers:** Urine output, lactate, and assessment of peripheral perfusion (capillary refill, extremity temperature).
* **IV site:** Check frequently for signs of infiltration/extravasation.
## Clinical Pearls
* **Administration:** Preferably administered through a central venous catheter. If peripheral administration is necessary, use a large vein (antecubital or larger) and for the shortest duration possible.
* **Extravasation Management:** If extravasation occurs, infiltrate the affected area with phentolamine (alpha-adrenergic antagonist) as soon as possible.
* **Compatibility:** Must be protected from light and diluted in D5W or D5NS; unstable in saline alone.
* **Titration:** Wean slowly to avoid rebound hypotension.
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*Disclaimer: This information is for educational purposes for healthcare professionals. Clinical dosing should be verified against institutional protocols and the most current FDA-approved prescribing information or clinical pharmacology databases.*
