Pharm

Norepinephrine

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Norepinephrine, Levarterenol, L-norepinephrine, Levonorepinephrine, Noradrenaline, Levophed

  • See Also
  1. Epinephrine
  2. Sympathomimetic Toxicity
  3. Sympathetic Nervous System
  4. Sympathomimetic
  5. Alpha Adrenergic Receptor
  6. Beta Adrenergic Receptor
  • Definitions
  1. Norepinephrine
    1. Natural Catecholamine, released from Adrenal Medulla as a stress response (along with Epinephrine)
    2. Also the primary postganglionic Neurotransmitter of the Sympathetic Nervous System
  • History
  1. Ulf Von Euler won 1970 Nobel Prize for its discovery
    1. Swedish Chemist also discovered Prostaglandins
  • Mechanism
  1. Naturally occurring Catecholamine
  2. Potent Alpha Adrenergic Receptor Agonist
    1. Potent arterial and venous Vasoconstriction
  3. Beta 1 Adrenergic Receptor Agonist
    1. Similar potency to Epinephrine
    2. Increases myocardial contractility
  4. No Beta 2 Adrenergic Receptor Activity
  • Indications
  1. Hemodynamically significant Hypotension
    1. Refractory to other Sympathomimetic amines
    2. Useful in Low Systemic Vascular Resistance
      1. Septic Shock
      2. Neurogenic Shock
  2. Temporizing measure only
  • Relative Contraindications
  1. Acute Myocardial Infarction
    1. Use as agent of last resort
  • Monitoring
  1. Monitor Blood Pressure accurately
    1. Consider Arterial Line with continuous monitoring
    2. Blood Pressure cuff monitoring every 5 minutes
  2. Consider advanced hemodynamic monitoring
    1. Cardiac Output
    2. Pulmonary wedge pressure
    3. Peripheral arterial resistance
  • Precautions
  1. Maximize management of other Hypotension causes first
    1. Maximize fluid Resuscitation in Sepsis
    2. Replace Blood Products in Trauma
  2. Use with caution in Myocardial Ischemia
    1. Increases myocardial oxygen requirements
    2. No compensatory increase in coronary perfusion
  3. Observe for Arrhythmias
    1. Volume depleted patents
    2. Limited myocardial reserve
  4. Norepinephrine is safest to use via central venous catheter
    1. However reliable large bore peripheral IV may be used safely with caution initially (e.g. first 24 hours)
      1. Nguyen (2020) Am J Emerg Med +PMID: 31959524 [PubMed]
    2. Extravasation may cause severe local tissue damage
    3. Antidote for extravasation
      1. Phentolamine 5-10 mg diluted in 10-15 ml NS
      2. Infiltrate area of extravasation with Phentolamine
  • Preparation
  1. Start with Norepinephrine (1 mg/ml) 4 ml ampule
  2. Mix 4 ml Norepinephrine in 250 ml D5W or Normal Saline
  3. Final Concentration: 16 ug/ml Norepinephrine
  • Dosing
  • Infusion via Central Venous Catheter
  1. Weight Based (preferred, adults)
    1. Start at 0.05 mcg/kg/min
    2. Unlikely to benefit from titration above 0.3 mcg/kg/min
  2. Non-weight based
    1. Start at 5 mcg/min (some recommend starting at 0.5 to 1.0 ug/min)
    2. Typical dose range (adults): 2 to 30 mcg/min
  3. Titrate to Systolic Blood Pressure over 90 mmHg
    1. Average Adult Dose: 2 to 12 ug/min
    2. Refractory Shock: up to 30 ug/min
  • References
  1. McCollum in Herbert (2019) EM:Rap 19(7):4-6