Noradrenaline

# Noradrenaline ## Overview - **Classification**: Alpha and beta-adrenergic agonist, vasopressor. - **Mechanism**: Directly stimulates alpha-1 adrenergic receptors (potent vasoconstriction) and beta-1 adrenergic receptors (increased cardiac contractility). Results in increased systemic vascular resistance (SVR) and blood pressure. ## Primary Indications 1. **Acute Hypotension/Shock**: Management of acutely hypotensive states unresponsive to fluid resuscitation. 2. **Septic Shock**: Vasopressor of choice for maintaining mean arterial pressure (MAP) targets. 3. **Cardiogenic Shock**: When associated with hypotension, often used with inotropes. ## Adult Dosing ### Standard Dosing **Acute Hypotension/Shock (e.g., Septic Shock)** - **Dose**: Initial infusion rate **0.01 - 0.03 mcg/kg/min** (or **0.5 - 1 mcg/min**). - **Frequency**: Continuous IV infusion. - **Route**: Via central venous catheter. - **Titration**: Titrate by **0.005 - 0.01 mcg/kg/min** (or **0.5 - 1 mcg/min**) every **2-5 minutes** to achieve target MAP (e.g., **65 mmHg**). - **Maximum Dose**: Up to **0.3 mcg/kg/min** (or **30 mcg/min**), higher doses may be used in severe cases. - **Duration**: As needed, often for hours to days, gradually weaned. ### Dose Adjustments - **Renal Impairment**: No specific dose adjustments; monitor hemodynamics closely. - **Hepatic Impairment**: No specific dose adjustments; monitor hemodynamics closely. - **Elderly Patients**: No specific dose adjustments; titrate carefully to effect due to potential increased sensitivity. ## Pediatric Dosing *All doses are via continuous IV infusion, preferably central line.* ### Neonates (0-28 days) - **Dose**: Initial **0.05 mcg/kg/min**. - **Frequency**: Continuous IV infusion. - **Titration**: Titrate by **0.005 - 0.01 mcg/kg/min** every **5-10 minutes** to achieve target BP. - **Maximum**: Up to **0.2 - 0.3 mcg/kg/min** (rarely higher). - **Special Notes**: Use diluted solutions carefully to avoid fluid overload. Monitor closely for extravasation and peripheral ischemia. ### Infants (1-12 months) - **Dose**: Initial **0.05 - 0.1 mcg/kg/min**. - **Frequency**: Continuous IV infusion. - **Titration**: Titrate by **0.005 - 0.01 mcg/kg/min** every **5-10 minutes**. - **Maximum**: Up to **0.3 mcg/kg/min**. ### Children (1-12 years) - **Dose**: Initial **0.05 - 0.1 mcg/kg/min**. - **Frequency**: Continuous IV infusion. - **Titration**: Titrate by **0.005 - 0.01 mcg/kg/min** every **5-10 minutes**. - **Maximum**: Up to **0.3 mcg/kg/min**. ### Adolescents (13-18 years) - **Dose**: Generally follow adult dosing guidelines. Initial **0.01 - 0.03 mcg/kg/min**. - **Frequency**: Continuous IV infusion. - **Maximum**: Up to **0.3 mcg/kg/min** (or **30 mcg/min**). ## Safety Information ### Contraindications - **Absolute**: Hypotension due to hypovolemia (unless adequate fluid resuscitation completed). - **Absolute**: Mesenteric or peripheral vascular thrombosis (risk of increased ischemia). - **Relative**: During cyclopropane or halothane anesthesia (risk of severe arrhythmias). ### Common Adverse Effects - **Very Common (>10%)**: Hypertension, bradycardia (reflex), headache, anxiety. - **Common (1-10%)**: Palpitations, arrhythmias, peripheral ischemia (cold, pale extremities), chest pain, dyspnea. - **Serious but Rare**: Extravasation leading to tissue necrosis, severe hypertension (cerebral hemorrhage), severe arrhythmias, acute renal failure. ### Key Drug Interactions - **MAO Inhibitors (MAOIs)**: Potentiation of vasopressor effect, severe hypertension. Avoid use; separate by at least 14 days. - **Tricyclic Antidepressants (TCAs)**: May potentiate pressor response. Monitor BP closely; consider lower initial noradrenaline dose. - **Alpha-blockers (e.g., Phentolamine)**: Antagonize pressor effect. Phentolamine can be used for extravasation. - **Beta-blockers (non-selective)**: May result in unopposed alpha-adrenergic effects, leading to severe hypertension and bradycardia. - **General Anesthetics (e.g., Halothane)**: May sensitize myocardium to noradrenaline, increasing risk of arrhythmias. Use with extreme caution. ## Monitoring & Follow-up - **Before Treatment**: Assess fluid status, electrolyte balance, and underlying cause of hypotension. - **During Treatment**: Continuous BP monitoring (arterial line preferred), heart rate, ECG, urine output (hourly), central venous pressure (CVP), arterial blood gases (ABGs), lactate. - **Clinical Signs**: Monitor for signs of ischemia (pallor, coolness, pain in extremities), arrhythmias, sudden changes in BP. ## Clinical Pearls - 💡 **Central Line**: Administer via central venous catheter to minimize risk of extravasation and tissue necrosis. - 💡 **Extravasation Management**: If extravasation occurs, infiltrate affected area with **phentolamine mesylate 5-10 mg** diluted in **10-15 mL saline**. - 💡 **Fluid First**: Always ensure adequate fluid resuscitation *before* starting noradrenaline, unless contraindicated or in extreme emergencies. - 💡 **MAP Target**: Titrate to achieve a predefined mean arterial pressure (MAP) target, typically **65 mmHg** in septic shock. - 💡 **Weaning**: Wean slowly as clinical condition improves to avoid rebound hypotension. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.