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noradrenaline

noradrenaline / norepinephrine

introduction

  • noradrenaline is the preferred 1st line vasopressor in Mx of sepsis / septicaemia not responding to iv fluid therapy
  • an endogenous sympathomimetic agent, its main action is as a alpha-1 agonist with beta-1 agonist actions and little beta-2 agonist actions (thus no skeletal muscle vasodilation nor the glucose metabolism effects as with adrenaline)
  • variable effect on HR and cardiac output:
    • low doses often result in vagal reflex bradycardia accompanying the rise in MAP, and thus cardiac output may even fall.
  • it's alpha-1 vasocontrictive actions (vasopressor) may result in reduced peripheral, pulmonary, renal and splanchnic perfusion.

adverse effects

  • allergy and hypersensitivity reactions in those sensitive to sulphites, take care in patients with PH asthma
  • tachycardia, potential risk of ventricular tachycardia (VT), especially if halogenated anaesthetics which sensitise the myocardium or in patients with acute myocardial infarction (AMI/STEMI/NSTEMI) or ischaemic heart disease.
  • hypertension
  • reflex bradycardia
    • may occur at low doses, and may actually reduce cardiac output
  • prolonged administration of any potent vasopressor may result in plasma volume depletion and hypotension
  • theoretical risk of increased myocardial ischaemia in patients with acute myocardial infarction (AMI/STEMI/NSTEMI)
  • vasoconstriction
    • use with care in those with heart disease, thyroid disease, hypertension, or diabetes
    • may cause local ischaemia and abscesses if used im or there is tissue extravasation at iv site
      • the antidote for extravasation ischaemia is local infiltration with phentolamine
    • prolonged vasoconstriction may prevent adequate volume expansion of circulation and lead to persistent shock

iv infusion

  • vials are usually 1mg/ml (1:1000) and in 4ml volumes (ie. 4mg)
  • dilute with 5% dextrose
  • note there are many drug incompatibilities - see P.I.

usual central line administration:

Victorian Safer care formulation 2019

  • add 4mL (4mg) of 1:1000 to 66mL 5% dextrose OR 6mL to 100mL 5% dextrose
  • concentration = 60mcg/mL
  • 1mL/hr = 1 microgram/min titrate as needed
  • usual starting dose 2-12 microgram/min
  • Usual dose range: 0.5 to 30microg/min
  • Maximum dose: up to 100 microg/min in extreme cases
  • should not be ceased abruptly.
noradrenaline.txt · Last modified: 2019/07/25 17:10 (external edit)