Nor%2525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252525252520epinephrine

# Norepinephrine ## Overview Norepinephrine is a potent vasopressor and inotropic agent that acts primarily on alpha-1 adrenergic receptors, causing vasoconstriction and increasing systemic vascular resistance. It also has some beta-1 adrenergic effects, increasing heart rate and contractility. ## Primary Indications * Severe hypotension and shock (e.g., septic shock, cardiogenic shock) unresponsive to adequate fluid resuscitation. ## Adult Dosing * **Initial:** 0.01 to 0.02 mcg/kg/min IV infusion. * **Titration:** Increase dose by 0.005 to 0.01 mcg/kg/min every 5-15 minutes as needed to achieve target mean arterial pressure (MAP) of 65 mmHg or higher. * **Maximum:** Doses up to 0.1 mcg/kg/min are common. Higher doses may be used in refractory shock, but effectiveness and safety at very high doses are less established. Dosing is highly individualized and guided by patient response. Local protocols may dictate specific titration parameters. ## Pediatric Dosing * **Initial:** 0.05 to 0.1 mcg/kg/min IV infusion. * **Titration:** Titrate to desired hemodynamic effect, typically to maintain SBP > 70 mmHg (neonate) or > 90 mmHg (child) or a target MAP based on age. Dosing may be increased up to 1 mcg/kg/min or higher. Consult specific pediatric critical care guidelines or protocols. ## Dose Adjustments * No dose adjustments are typically required for hepatic or renal impairment, as norepinephrine is rapidly metabolized. However, underlying organ dysfunction may affect patient tolerance and response. ## Contraindications * Hypersensitivity to norepinephrine. * Generally not recommended in patients with mesenteric or peripheral vascular thrombosis, as it may further compromise blood flow to these areas. ## Adverse Effects * **Cardiovascular:** Hypertension, reflex bradycardia, arrhythmias (including ventricular), myocardial infarction, peripheral ischemia, extravasation leading to tissue necrosis. * **Other:** Headache, anxiety, tremors, cold extremities. ## Key Drug Interactions * **Monoamine Oxidase Inhibitors (MAOIs):** May potentiate hypertensive crisis. Avoid concurrent use or use with extreme caution and lower initial doses. * **Tricyclic Antidepressants (TCAs):** May potentiate hypertensive effects. Use with caution. * **Beta-blockers:** May cause unopposed alpha-adrenergic stimulation, leading to severe hypertension. * **Anesthetic agents:** Can potentiate arrhythmias. ## Monitoring * **Hemodynamics:** Continuous blood pressure monitoring (arterial line preferred), heart rate, cardiac rhythm. * **Urine Output:** Monitor for adequate perfusion. * **Extremities:** Assess for signs of peripheral ischemia (color, temperature, capillary refill). * **Infusion Site:** Monitor closely for signs of extravasation. ## Clinical Pearls * Administer via a central venous catheter to minimize risk of extravasation and tissue necrosis. * If extravasation occurs, discontinue the infusion and administer phentolamine (intradermal injection) to the affected area. * Norepinephrine should be diluted in a compatible IV fluid (e.g., D5W, NS) before administration. Common concentrations are 4 mg/250 mL or 8 mg/250 mL. * Titrate to achieve desired MAP, not necessarily a specific dose. *** *This information is intended for healthcare professionals. Always consult the official prescribing information and current clinical guidelines for complete details and to verify dose accuracy.*