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# Norepinephrine
## Overview
Norepinephrine is a potent catecholamine with primary alpha-1 adrenergic agonist activity (vasoconstriction) and moderate beta-1 adrenergic agonist activity (inotropic effect). It is the first-line vasopressor for septic shock.
## Primary Indications
* Acute hypotensive states (e.g., septic, cardiogenic, or vasodilatory shock).
* Adjunct in the treatment of cardiac arrest (though epinephrine remains standard).
## Adult Dosing
* **Initial:** 0.01 to 0.05 mcg/kg/min continuous IV infusion.
* **Titration:** Titrate to achieve target mean arterial pressure (MAP), usually ≥65 mmHg. Typical range is 0.01 to 3 mcg/kg/min.
* **Maximum:** No absolute maximum dose; however, clinical status should be reassessed at high doses due to severe peripheral ischemia risk.
## Pediatric Dosing
* **Initial:** 0.05 to 0.1 mcg/kg/min continuous IV infusion.
* **Titration:** Titrate to clinical effect (e.g., target perfusion/MAP); range typically 0.05 to 2 mcg/kg/min.
## Dose Adjustments
* **Renal/Hepatic Impairment:** No specific adjustment required, but use caution as these patients may be more sensitive to hemodynamic fluctuations.
* **Titration Protocol:** Dose based on local hospital policy; always titrate to the lowest effective dose.
## Contraindications
* Hypotension due to uncorrected hypovolemia (volume resuscitation must be priority).
* Mesenteric or peripheral vascular thrombosis (except in life-threatening emergencies).
## Adverse Effects
* **Most Common:** Hypertension, arrhythmias (tachycardia/bradycardia).
* **Serious:** Tissue necrosis/extravasation (risk of skin sloughing if leaked), peripheral ischemia (fingers/toes), bowel ischemia, and anxiety.
## Key Drug Interactions
* **MAO Inhibitors / TCAs:** May cause severe, prolonged hypertensive crisis.
* **Alpha/Beta Blockers:** May antagonize the pressor effects of norepinephrine.
* **General Anesthetics (Halogenated hydrocarbons):** May increase myocardial sensitivity to catecholamines, elevating risk of arrhythmias.
## Monitoring
* **Hemodynamics:** Continuous MAP/BP monitoring (preferably arterial line for titration).
* **Perfusion:** Peripheral perfusion status (check for cold/mottled extremities).
* **IV Site:** Assess for signs of extravasation frequently.
* **Labs:** Serum lactate, urine output, and EKG for arrhythmias.
## Clinical Pearls
* **Administration:** Must be administered via a large peripheral vein (only temporarily) or central venous line to prevent necrosis.
* **Extravasation Management:** If extravasation occurs, discontinue infusion and infiltrate the area with phentolamine (alpha-adrenergic antagonist) as soon as possible.
* **Compatibility:** Must be administered in 5% Dextrose (D5W) to prevent oxidation. Always verify Y-site compatibility before co-infusing.
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**Educational Disclaimer:** This information is for educational purposes only. Drug dosing, compatibility, and infusion guidelines vary by institutional protocol and patient-specific factors. Always consult the official prescribing information, hospital-specific formularies, and clinical pharmacy specialists before administration.
