Local Anesthetics

Front 1

Classification

Back 1

Esters:
Tetracaine (long acting)
Cocaine (medium duration)
Procaine (short acting)
Benzocaine (surface acting)

Amides:
Bupivacaine (long duration)
Lidocaine (medium duration)
One “I” for esters and two “I”s for amides

Front 2

Benzocaine-

Back 2

spray form

Front 3

Significance of classification

Back 3

Cross hypersensitivity possible only within groups
Ester LA’s are metabolized by buterylcholinestarases/pseudocholinesterase
Amide LA’s are metabolized by CYP-450 enzymes

Front 4

MOA

Back 4

Binds to the receptor site on the sodium channel from inside of the cell
Acts by blocking the voltage gated sodium channels

Front 5

Infected tissue

Back 5

Acidosis in the environment (infected/abcess/pus tissue) into which the local anesthetic is injected further increases the ionized fraction of drugs.
This is the reason for slower onset and poor quality of local anesthesia when a local anesthetic is injected into an acidic infected area.

Front 6

Q; ptn given local anthesia, has liver probs; later on has toxicity, what type was he given?

Back 6

Amides

Front 7

Pharmacokinetics

Back 7

Local anesthetics (LAs) are readily absorbed into the blood
This limits the duration of action
Duration of action can be prolonged by giving a vasoconstrictor along with the local anesthetic agent

Front 8

Cocaine is different-

Back 8

good anesthesis- do need to be given with epinpherine!!!! It blocks cathecholine reuptake pump- causes vasoconstriction
Never use on end arteries! (finger tips, toes etc; cause necrosis)

Front 9

Bupivacaine

Back 9

severe arrhythmias and hypotension

Front 10

LA + Epinephrine

Back 10

added to prolong a local anesthetic's duration of action by producing vasoconstriction and slowing its rate of absorption.
Because of the risk of ischemia and necrosis LA with epinephrine is not used to anesthetize tissues with end arteries
They are tissues of the fingers, toes, ears, nose, and penis.