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# Norad (norepinephrine)
## Overview
Norepinephrine is a catecholamine vasopressor predominantly acting on alpha-1 adrenergic receptors, with mild beta-1 activity. It is first-line for septic shock and other vasodilatory shock states.
## Primary Indications
- Hypotension refractory to fluid resuscitation, especially in septic shock
- Neurogenic shock
- Distributive shock (e.g., anaphylaxis, spinal cord injury)
## Adult Dosing
- **IV infusion**: Start at 0.05–0.1 mcg/kg/min; titrate by 0.05–0.1 mcg/kg/min every 5–10 minutes to achieve target mean arterial pressure (typically ≥65 mmHg).
- **Typical range**: 0.05–0.5 mcg/kg/min; maximum commonly 1–2 mcg/kg/min (higher doses may be used per protocol but increase adverse event risk).
- **Concentration**: standard mix: 4 mg norepinephrine base per 250 mL D5W (16 mcg/mL). Follow local protocol.
## Pediatric Dosing
- **IV infusion**: Start 0.05–0.1 mcg/kg/min; titrate every 5–10 minutes.
- **Usual range**: 0.05–0.5 mcg/kg/min; maximum up to 1–2 mcg/kg/min (limit data; use with caution).
- **Central venous access strongly preferred** due to extravasation risk.
## Dose Adjustments
- **Renal impairment**: No adjustment needed.
- **Hepatic impairment**: No established adjustment; monitor for exaggerated effect.
- **Hypovolemia**: Correct volume deficit before/during administration; vasopressors ineffective in hypovolemia.
## Contraindications
- Hypersensitivity to norepinephrine or sulfites (some formulations contain sulfites)
- Untreated hypovolemia
- Mesenteric or peripheral vascular thrombosis (risk of ischemia exacerbation)
## Adverse Effects
- **Common**: hypertension, tachycardia (reflex or direct), bradycardia, arrhythmias
- **Serious**: extravasation necrosis, limb ischemia, renal/mesenteric ischemia (especially with prolonged high doses), pulmonary edema
- **Extravasation management**: phentolamine 5–10 mg in 10 mL saline infiltrated locally
## Key Drug Interactions
- **MAOIs, linezolid, methylene blue**: potentiate pressor effect → severe hypertension (reduce norepinephrine dose by 90% and titrate cautiously)
- **Tricyclic antidepressants, SNRIs**: increased risk of hypertensive crisis
- **Beta-blockers**: unopposed alpha-mediated vasoconstriction (hypertension)
- **Ergot alkaloids**: synergistic vasoconstriction → ischemia
## Monitoring
- Continuous blood pressure (invasive arterial preferred), heart rate, ECG for arrhythmias
- Urine output, peripheral perfusion (capillary refill, skin color/temperature)
- Signs of extravasation: IV site q1h (especially with peripheral lines)
- Serum lactate and pH as markers of shock resolution
## Clinical Pearls
- **First-line vasopressor in septic shock** (Surviving Sepsis Campaign guidelines).
- **Central line recommended**; if peripheral, use large antecubital vein and limit duration to <2 hours.
- **Wean slowly** after shock resolution – do not abruptly stop.
- **Correct hypovolemia first** to avoid severe vasoconstriction in empty vessels.
- **Acidosis reduces sensitivity** – titrate to effect; consider alternative pressor if high doses needed.
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*This information is for educational purposes and does not replace clinical judgment. Verify dosing and indications against local protocols and current prescribing information.*
