Pharm 101: Lignocaine


Local anaesthetic
Class IB antiarrhythmic

  • Class IB antiarrhythmic drug that shortens action potential duration
  • Blocks activated and inactivated Na channels with rapid kinetics
  • Inactivated state block means greater effect on cells with long action potentials such as Purkinje fibres and ventricular cells, compared with atrial cells
  • No effect on conduction
  • Can be administered via ETT
  • Given IV due to extensive first pass metabolism
  • Half-life 1-2 hours
Clinical uses
  • Arrhythmias associated with MI
  • VT
  • Local anaesthetic
  • Maximum dose:
    • 4mg/kg plain
    • 7mg/kg with adrenaline
Adverse effects
  • Dose-related and short-lived
  • Transient neurological symptoms:
    • Paraesthesias
    • Tremor
    • Nausea
    • Tinnitus
  • Toxicity:
    • CVS: proarrhythmic effects, hypotension in CCF, cardiovascular collapse
    • CNS: metallic taste in mouth, tongue numbness, sedation, hallucinations, seizures
  • Reduce dose in heart failure or liver disease
Further Reading

Pharmacology 101

Top 200 drugs

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Adult/Paediatric Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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