Please check your internet connection and try again.
# Norepinephrine
## Overview
Norepinephrine is a potent vasopressor that stimulates alpha-adrenergic receptors, causing vasoconstriction and increasing peripheral vascular resistance and blood pressure. It also has beta-1 adrenergic effects, increasing heart rate and contractility.
## Primary Indications
* Treatment of hypotension (low blood pressure) in severe distributive shock states (e.g., septic shock, neurogenic shock).
## Adult Dosing
* **Starting Dose:** 0.01 to 0.02 mcg/kg/min intravenously (IV).
* **Titration:** Gradually increase dose by 0.005 to 0.01 mcg/kg/min every 5-10 minutes to achieve target mean arterial pressure (MAP) of 65 mmHg or higher.
* **Maximum Dose:** Typically 0.1 mcg/kg/min, but may be higher in some refractory cases per institutional protocol. Doses exceeding 0.3-0.4 mcg/kg/min are rarely used and associated with significant adverse effects.
## Pediatric Dosing
* **Starting Dose:** 0.05 to 0.1 mcg/kg/min IV.
* **Titration:** Gradually increase dose by 0.05 to 0.1 mcg/kg/min every 5-10 minutes to achieve target MAP or blood pressure goals (often similar to age in years + 2 times systolic blood pressure, or a specific target like 50-70 mmHg).
* **Maximum Dose:** Typically 1-2 mcg/kg/min, though doses may vary significantly based on clinical context and institutional guidelines.
## Dose Adjustments
* **Renal Impairment:** No specific dose adjustment, but may require higher doses due to altered pharmacokinetics. Close monitoring is essential.
* **Hepatic Impairment:** No specific dose adjustment, but may require higher doses. Close monitoring is essential.
## Contraindications
* Hypersensitivity to norepinephrine.
* Hypotension due to volume deficits before correction.
* Use of cyclopropane or halogenated hydrocarbon anesthetics (risk of severe arrhythmias).
## Adverse Effects
* **Common:** Hypertension, bradycardia (reflex), peripheral ischemia, tissue necrosis (extravasation), headache, anxiety, dizziness, tremors, nausea, vomiting.
* **Serious:** Arrhythmias, severe hypertension, decreased cardiac output (at high doses), rebound hypotension upon discontinuation, gangrene.
## Key Drug Interactions
* **Monoamine Oxidase Inhibitors (MAOIs):** Potentiates hypertensive crisis. Avoid concurrent use. If necessary, use extreme caution and reduce norepinephrine dose significantly.
* **Tricyclic Antidepressants (TCAs) and Cocaine:** Potentiates hypertensive crisis and arrhythmias. Avoid concurrent use.
* **Beta-blockers:** May cause unopposed alpha-stimulation leading to severe hypertension.
* **Ergot Alkaloids and Oxytocin:** May cause severe hypertension and peripheral ischemia.
* **Alpha-adrenergic Blockers (e.g., prazosin, terazosin):** May reduce pressor effect.
* **Anesthetics (volatile):** Increased risk of arrhythmias.
## Monitoring
* Continuous electrocardiogram (ECG) monitoring.
* Continuous blood pressure monitoring via arterial line.
* Urine output.
* Peripheral perfusion (e.g., skin temperature, capillary refill, color).
* Central venous pressure (CVP) and/or pulmonary artery pressures (if available).
* Mental status.
## Clinical Pearls
* Norepinephrine should be administered via a central venous catheter to minimize the risk of extravasation and tissue necrosis.
* If extravasation occurs, stop the infusion immediately and infiltrate the area with phentolamine mesylate to counteract vasoconstriction.
* Taper the infusion gradually to avoid rebound hypotension.
* Ensure adequate intravascular volume before initiating or titrating norepinephrine.
* Consider vasopressin and/or corticosteroids in addition to norepinephrine for septic shock management per current guidelines.
***
**Disclaimer:** This information is intended for healthcare professionals and does not replace the need to consult the official prescribing information and current clinical guidelines for the specific product and patient. Always verify the most up-to-date drug information before making clinical decisions.
