Noradrenaline (Norepinephrine)

Last updated 30/10/14

Definition

• Catecholamine produced by adrenal medulla and sympathetic nervous system with vasopressor and positive inotropic effects

Features

• Sympathomimetic amine vasopressor
• Differs from Adrenaline by absence of methyl group
• Short duration of action
• Ideally run via Central Venous Catheter (CVC) or Peripherally Inserted Central Catheter (PICC) line
• May be run via large peripheral cannula for short duration if essential

Indications

• Hypotension
• If persists after volume replacement
• Perioperative
• Acute Myocardial Infarction (AMI) with hypotension
• Increases aortic blood pressure, coronary artery blood flow and myocardial oxygenation
• Limits myocardial ischaemia and infarction

Mechanism

• Adrenergic agonist
• Alpha adrenergic
• Peripheral vasoconstriction
• Beta adrenaregic
• Positive ionotrope
• Coronary artery dilation
• Increases BP, cardiac output plus renal, splanchnic, cerebral & microvascular blood flow
• Minimally increases HR
• Venodilates increasing venous return & cardiac preload

Dosing

• IV only
• Ampules: 1mg/ml
• 2mg in 2ml
• 4mg in 4ml
• Premixed bag: 10mg in 100ml (0.1mg/ml)
• IV Infusion
• 6mg in 100mls (60mcg/ml)
• Commence at 1ml/hr (1mcg/min) titrated to effect (review at 20mcg/min)

Side Effects/Precautions/Contraindications

• Side Effects
• Extravasation with possible vasoconstriction and necrosis
• Administer Phentolamine 5-10mg with 10-15ml NS
• Tachycardia
• Bradycardia in response to elevated BP
• Arrythmias
• Anxiety
• Transient headache
• Precautions
• Cautious use in patients on Monoamine Oxidase Inhibitors (MAOIs), triptyline or imipramine Antidepressants: severe prolonged hypertension
• Contraindications
• Sulphite sensitivity: anaphylaxis
• Hypotension from volume depletion
• May cause severe peripheral and visceral vasoconstriction
• Decreased renal perfusion and urine output
• Tissue hypoxia and lactic acidosis
• Mesenteric or peripheral vascular thrombosis: increases ischaemia
• Cyclopropane or Halothane anaesthetics: Ventricular Tachycardia (VT), Ventricular Fibrillation (VF)

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References

1. Life in the Fast Lane: Noradrenaline