Local anaesthetics

Question 1

Uses

Answer 1

Inhibit pain by preventing impulse conduction along sensory nerves
Used in dental and plastic surgery
Anti- dysrthymic ( cardiac action prevents reentrant impulses)
Used in epilepsy

Question 2

General structure

Answer 2

Aromatic group, ester or amide link and amine group.

Question 3

Mechanism of action

Answer 3

Block voltage operated Na+ channels on neuronal membranes, preventing ap generation and propogation.
An allosteric agonist of inactivation

Question 4

Inactivation of local anaesthetics

Answer 4

Enzymatic hydrolysis by non-specific esterases

Question 5

Neural sensitivity to local anaesthetics

Answer 5

Smaller fibres > larger fibres
Myelinated fibres > non myelinated fibres
Pain > temp > touch > pressure

Question 6

Routes of administration

Answer 6

Topical
Infiltration
Regional

Question 7

Adverse effects

Answer 7

CNS; agitation and convulsions

CVS; vasodilation and decreased cardiac output.