Local Anaesthetics

L O CA L A N A E S T H E T I CS

S O D I U M C H A N NE L B L O C K E R S : B E NZ O C A I NE , L I G NO C A I NE

M E C H A N I S M O F A C T I O N • Binds to the S6 subunit of the sodium channel, reducing its permeability for sodium influx into the neuron, thus no depolarisation and propagation of action potentials. • Usually affects pain fibres first due to lower myelination as well as smaller diameter making them more susceptible to drug effects.

I N D I C A TI O N S :

• Reduce sensation, especially pain of peripheral area before simple surgical procedures

S I D E E F F E C TS :

• Further CNS depression, drowsiness which can progress into a coma. • Respiratory depression, which can lead to asphyxiation • Drugs such as lignocaine, which have a longer duration of action (due to slower metabolism by microsomal enzymes), can further contribute to side effects