Norad%2525252525252525252520%2525252525252525252528norepinephrine%2525252525252525252529

# Norepinephrine ## Overview Norepinephrine is a potent catecholamine with alpha-1 and beta-1 adrenergic agonist activity. It primarily induces systemic vasoconstriction (increasing systemic vascular resistance) and provides modest inotropic support, with minimal chronotropic effect at standard doses. ## Primary Indications - Hypotension/Shock: First-line vasopressor for distributive (septic), cardiogenic, and hypovolemic shock refractory to fluid resuscitation. ## Adult Dosing - **Initial:** 0.05 to 0.1 mcg/kg/min or 2 to 4 mcg/min via continuous infusion. - **Titration:** Titrate to achieve target Mean Arterial Pressure (MAP), typically ≥65 mmHg. - **Usual Maintenance Range:** 0.01 to 3 mcg/kg/min. - **Maximum:** Theoretically no absolute maximum; however, doses exceeding 1–3 mcg/kg/min signify profound refractory shock and necessitate consideration for secondary pressors (e.g., vasopressin). ## Pediatric Dosing - **Initial:** 0.05 to 0.1 mcg/kg/min. - **Titration:** Titrate by 0.05 to 0.1 mcg/kg/min every 5–15 minutes based on clinical response. - **Maximum:** Up to 2 mcg/kg/min. *Note: Site-specific protocols may vary significantly. Always utilize weight-based dosing for pediatrics.* ## Dose Adjustments - **Hepatic/Renal:** No specific dose adjustments are typically required; however, clinical response may be altered by multi-organ dysfunction. - **Weaning:** Taper dose gradually as hemodynamic stability improves to prevent rebound hypotension. ## Contraindications - Hypersensitivity to norepinephrine. - Hypotension due to uncorrected blood volume depletion (except as an emergency measure). - Mesenteric or peripheral vascular thrombosis (relative contraindication). ## Adverse Effects - **Common:** Hypertension, arrhythmias (tachycardia/bradycardia), headache, anxiety. - **Severe:** Tissue ischemia, necrosis (due to extravasation), mesenteric ischemia, lactic acidosis, bradycardia (reflex). ## Key Drug Interactions - **MAO Inhibitors / TCAs:** May result in severe, prolonged, or unpredictable hypertension. - **Beta-blockers:** May result in excessive alpha-mediated vasoconstriction (unopposed alpha response). - **Inhaled Anesthetics (e.g., Halothane/Cyclopropane):** Increased risk of arrhythmias due to sensitization of the myocardium to catecholamines. ## Monitoring - **Hemodynamics:** Continuous invasive arterial blood pressure monitoring is strongly recommended. - **Access:** Verify patency of large-bore peripheral or central venous access; monitor site frequently for infiltration/extravasation. - **Organ Perfusion:** Urine output, extremity perfusion, serum lactate, and EKG for cardiac rhythm. ## Clinical Pearls - **Extravasation Risk:** Norepinephrine is a strong vesicant. If extravasation occurs, stop the infusion immediately and consider local infiltration with **phentolamine** (alpha-antagonist) to prevent tissue necrosis. - **Administration:** Central venous access is preferred to minimize the risk of peripheral tissue damage, though short-term peripheral administration via a large-bore proximal vein is acceptable in emergency settings according to current guidelines. - **Compatibility:** Ensure medication compatibility with maintenance fluids (use D5W or D5NS; saline can sometimes lead to oxidative degradation over time, though protocols vary). *** **Disclaimer:** This information is for educational purposes only. Drug protocols, concentration standards (e.g., dosing units per mL), and contraindications can vary significantly by clinical setting and regional guidelines. Always verify dosing and administration requirements with your institution’s current prescribing information and pharmacy protocols before administration.