1. Local Anaesthetics

2. Local anaesthetics (L.A’s) are drugs that produce reversible inhibition of conduction along nerves
Small sensory nerves are most affected, but in large doses large nerves (motor nerves) could be affected

3. L.A’s methods of application:
- Direct application to mucus membranes and skin
- Intradermal, local infiltration or S.C
- Epidural injection, spinal or subararachnoid injection
- I.V extremity block

4. L.A’s dosage forms:
Creams, pastes, ointments, oral lozenges, suppositories and solutions for injection...
Use of vasoconstrictors with L.A’s:
Most commonly used AD (EP) or felypressin (ADH-like drug)
Major purpose of adding a vasoconstrictor:
- To extend DOA of L.A
- To limit bleeding and to decrease or inhibit LA systemic absorption

5. L.A’s side effects:
Allergy, convulsions, cardiac & respiratory depression
Lidocaine (lignocaine; xylocaine)
Most widely used L.A in all types of local anaesthesia
Also has an antiarrhythmic effect (given I.V) used in certain types of cardiac arrhythmia

6. Prilocaine
Similar to lidocaine but has longer DOA, widely used in dentistry
Has unique side effect:
Methemoglobinemia
Bupivacaine
Widely used in epidural anaesthesia
Has slower OOA as compared to lidocaine

7. Amethocaine & oxybuprocaine
Toxic L.A’s only used as L.A’s in the eye
Cocaine
Has marked CNS stimulant effect and sympathomimetic effects
Produces vasoconstriction and euphoria
Used as a surface anaesthesia in eye, throat and nasal surgery
It produces addiction (major disadvantage)