Summary LOCAL ANESTHETICS (LA)

VS




LOCAL ANESTHETICS (LA)
Local Anesthetics are the drugs which upon topical
application and local injection cause reversal loss of sensory.

They are the only drugs used clinically to block the voltage
gated sensitive sodium channels and inhibit generation of
action potential.

LAs are either esters or amides.

Esters are rapidly hydrolyzed by plasma and tissue esterases
and

Amides are metabolized in liver



CLASSIFICATION :

Local anaesthertics are divided into two major categories :

-INJECTABLE ANESTHETICS

-SURFACE ANESTHETICS

Injectable Anesthetics is further divided into 3 sub
categories :

, VS



-High Potency Duration : Procaine , Chloroprocaine

-Intermediate Duration : Lidocaine , Prilocaine

-High Potency and Duration : Tetracaine , Bupivacaine ,
Ropivacaine

Surface Anesthetics is sub divided into 2 categories :

-Soluble : Cocaine , Lidocaine , tetracaine , Proparacaine

-Insoluble : Benzocaine , Butylaminobenzoate , Oxethazaine



MECHANISM OF ACTION :

The LA block nerve conduction by decreasing the entry of
Sodium Ions during upstroke of action potential.

When concentration of LA will increase , rate of action
potential will also increase which will cause Depolarization
and will result in slow conduction.

Local depolarization fails to reach the threshold potential
and conduction blocks.



At physiological pH,