Pharm 101: Lignocaine

Class

Local anaesthetic
Class IB antiarrhythmic


Pharmacodynamics
  • 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

Pharmacokinetics
  • 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

Precautions/contraindications
  • Reduce dose in heart failure or liver disease

Further Reading

Pharm 101 700

Pharmacology 101

Top 200 drugs

MBBS (UWA) CCPU Emergency Medicine Trainee with interests in medical education, ECG interpretation, and the use of point-of-care ultrasound in the undifferentiated patient. Co-author of the LITFL ECG Library | Twitter

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