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# Norepinephrine (Noradrenaline)
## Overview
Norepinephrine is a potent catecholamine with primary alpha-1 agonist activity resulting in profound peripheral vasoconstriction and moderate beta-1 agonist activity leading to increased inotropy. It is the first-line vasopressor for septic shock.
## Primary Indications
* Acute hypotensive states (e.g., septic, cardiogenic, or neurogenic shock)
* Adjunct treatment during cardiac arrest (though epinephrine is preferred)
## Adult Dosing
* **Initial Infusion:** 0.01 to 0.05 mcg/kg/min or 2–4 mcg/min (fixed rate).
* **Titration:** Titrate to target Mean Arterial Pressure (MAP) (typically ≥65 mmHg). Usual maintenance range is 0.05–0.5 mcg/kg/min, though refractory cases may require >1 mcg/kg/min.
* **Maximum:** No strict pharmacologic maximum; however, escalating doses reflect severe underlying pathology/refractory shock. High doses (e.g., >1 mcg/kg/min) are associated with severe peripheral ischemia.
## Pediatric Dosing
* **Continuous Infusion:** 0.05 to 0.1 mcg/kg/min.
* **Titration:** Titrate by 0.05 mcg/kg/min every 5–10 minutes based on perfusion and blood pressure goals.
* **Maximum:** Up to 1–2 mcg/kg/min in pediatric intensive care under strict hemodynamic monitoring.
## Dose Adjustments
* **Hepatic/Renal Impairment:** No standard dosage adjustments provided in labeling; monitor hemodynamic response closely.
* **Older Adults:** Use caution; may be more sensitive to vasoconstrictive effects.
## Contraindications
* None in emergency/crisis settings. Use with extreme caution in patients with peripheral vascular thrombosis or mesenteric/peripheral vascular ischemia.
## Adverse Effects
* **Common:** Hypertension, tachycardia, arrhythmias.
* **Severe:** Extravasation causing tissue necrosis (sloughing), limb ischemia, mesenteric ischemia, anxiety, headache.
## Key Drug Interactions
* **MAO Inhibitors / TCAs:** May cause severe, prolonged hypertension.
* **Beta-Blockers (Non-selective):** May lead to unopposed alpha-mediated vasoconstriction (severe hypertension and reflex bradycardia).
* **Halogenated Hydrocarbons (e.g., anesthetics):** Increased risk of arrhythmias.
## Monitoring
* **Continuous:** Continuous intra-arterial blood pressure monitoring (preferred for titration).
* **Safety:** Examine infusion site frequently for extravasation (sign: blanching/cold skin).
* **Clinical:** Heart rate, rhythm (ECG), urine output, peripheral perfusion/capillary refill, and serum lactate levels.
## Clinical Pearls
* **Extravasation Management:** If extravasation occurs, stop the infusion immediately and infiltrate the area with **phentolamine** (alpha-antagonist) per institutional protocol.
* **Central Line:** Preferred route for administration to avoid extravasation; can be used in a large peripheral vein temporarily if necessary, but transition to central access promptly.
* **Volume Status:** Norepinephrine is ineffective in hypovolemic patients; ensure adequate fluid resuscitation prior to or concurrent with initiation.
* **Institutional Protocol:** Always consult your facility's specific drug infusion guidelines, as concentrations (dilutions) and titration schedules vary by hospital policy.
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*Educational Disclaimer: This information is for educational purposes only. Clinical practice guidelines vary by institution. Always verify current prescribing information, institutional protocols, and patient-specific factors before administration.*
