Please check your internet connection and try again.
# Norepinephrine
## Overview
Norepinephrine is a potent catecholamine with primary alpha-1 adrenergic agonist activity (vasoconstriction) and moderate beta-1 adrenergic activity (inotropic effect). It is the first-line vasopressor for septic shock.
## Primary Indications
* Acute hypotension (e.g., septic, cardiogenic, or neurogenic shock)
* Adjunctive therapy in cardiac arrest (off-label)
## Adult Dosing
* **Initial:** 0.01 to 0.05 mcg/kg/min (or 5–30 mcg/min).
* **Titration:** Titrate by 0.01–0.05 mcg/kg/min every 3–5 minutes to achieve target Mean Arterial Pressure (MAP), typically ≥65 mmHg.
* **Maintenance Range:** 0.05 to 0.5 mcg/kg/min.
* **Maximum:** Doses >1–3 mcg/kg/min are sometimes used in refractory shock, but clinical benefit diminishes as risk of tissue ischemia increases.
* *Note: Dosing depends heavily on local institutional protocols and hemodynamic monitoring.*
## Pediatric Dosing
* **Continuous Infusion:** 0.05 to 1 mcg/kg/min, titrated to achieve age-appropriate blood pressure goals.
* *Note: Always verify doses against pediatric weight-based protocols; use central venous access whenever possible.*
## Dose Adjustments
* **Renal/Hepatic Impairment:** No specific dosage adjustments provided in manufacturer labeling; however, cautious titration is required as clearance may be altered in critically ill patients with multi-organ failure.
## Contraindications
* Hypersensitivity to norepinephrine or sulfite sensitivity.
* Hypotension due to uncorrected blood volume deficit (except as an emergency measure to maintain coronary/cerebral perfusion).
## Adverse Effects
* **Common:** Hypertension, headache, anxiety.
* **Serious:** Tissue necrosis/sloughing at extravasation site, severe peripheral/visceral ischemia, bradycardia (reflex), cardiac arrhythmias, hyperglycemia.
## Key Drug Interactions
* **MAO Inhibitors/Antidepressants (TCAs):** Can cause severe, prolonged hypertension due to inhibited metabolic degradation or reuptake.
* **Non-selective Beta-blockers:** May lead to unopposed alpha-adrenergic-mediated vasoconstriction and severe hypertension.
* **General Anesthetics (halogenated hydrocarbons):** Increased propensity for cardiac arrhythmias.
## Monitoring
* **Continuous:** Continuous intra-arterial blood pressure monitoring (preferred) and ECG for arrhythmias.
* **Clinical:** Assess perfusion status (capillary refill, mental status, urine output, serum lactate).
* **Access:** Inspect infusion site frequently for signs of extravasation.
## Clinical Pearls
* **Extravasation Management:** If extravasation occurs, stop the infusion immediately. Phentolamine infiltration into the affected area is the standard antidote to neutralize alpha-mediated vasoconstriction.
* **Line Placement:** Administer via a large-bore central venous catheter whenever possible to minimize the risk of skin necrosis.
* **Compatibility:** Must be diluted in D5W or D5NS; Norepinephrine is incompatible with alkaline solutions (e.g., sodium bicarbonate).
* **Weaning:** Wean slowly to avoid rebound hypotension; consider transitioning to enteral vasopressors (e.g., midodrine) if appropriate per specific unit protocols.
***
*Disclaimer: This information is for educational purposes only and does not replace professional clinical judgment. Always verify dosages, contraindications, and compatibility with the most current institutional protocols and the manufacturer's prescribing information before administration.*
