Lignocaine — Classification & Pharmacology

Current · V5 (2025) → H6.ii Historical · V4 (2023) → K2.ii 1 exam appearance

2014A Q17

Exam question

Classify local anaesthetic agents and give examples. (30% of marks) Describe the pharmacology of lignocaine. (70% of marks)

CICMWrecks answer

Master answer

Local anaesthetic agents act via inhibition of voltage gated Na+ channels, by binding to the intracellular portion of the channel
- → Decreased Na influx
- → Inhibition of depolarization
- → Inhibition of action potential formation and propagation
Local anaesthetics are formed by a hydrophobic and hydrophillic component, and are classified according to the linkage between the two, either amide or ester
Amide Local Anaesthetics
- e.g. Lignocaine, ropivacaine, bupivacaine
- Metabolized by hepatic dealkylation by P450 enzymes
- Longer duration of action
Ester Local Anaesthetics
- e.g. Procainamide, cocaine
- Metabolized by plasma esterases
- Shorter duration of action

Mooney / JC 2019

Answer by JC, Mooney

Past papers

1 appearance

Exam	Exact exam wording	Candidate success
2014A Q17	Classify local anaesthetic agents and give examples. (30% of marks) Describe the pharmacology of lignocaine. (70% of marks)	71%