Local Anaesthetics

Question 1

Lidocaine
-MOA
-adverse effects and treatment
-drug interactions

Answer 1

Blocks Na channels => nerves cannot conduct signals

Onset - 1-5mins
Duration 0 1-2hrs

Toxicity if too much given or IV
-CNS overactivity the depression as both inhibitory and activating pathways are blocked
-cardiac arrythmias
TREAT WITH IV 20% LIPID EMULSION

AVOID if also on Bb

Question 2

Cocaine
-use

Answer 2

Limited use in ENT - applied to nasal mucosa

Rapid onset, marked VC

Question 3

Bupivicaine
-MOA
-adverse effects

Answer 3

Binds to intracellular portion of VGNaC => blocks Na influx into nerve cells => depolarisation can’t take place

Onset - 10-15mins
Duration 8hrs

CARDIOTOXIC

Question 4

Use of LA with adrenaline

Answer 4

Prolongs duration of action
VC => can use higher doses except bupivicaine

Cannot use adrenaline with MAOinh or TCAs