10 Local Anesthetics Flashcards
What is the MOA of local anesthetics?
Na channel blocker
-> reduce frequency of AP
What fibers are most affected by local anesthetics?
C- Fibers
Thin
Pain signals
What is local anesthesia pKa?
8-9
What happens with local anesthetics when there is an infection or inflammation?
Theres a lower pH
More drug is required
How do you increase the amount of local anesthetic ale to cross the membrane?
Increase pH – more local becomes available
How is local anesthesia injected into the tissue?
Extravenous injection
What volume is required for spinal and epidural anesthesia?
Spinal - low
Epidural - large
What drug is used to decrease the rate of systemic absorption of a local anesthetic?
EPI – Vasoconstrictors
Inc potency
What local anesthetics belong to the Ester class?
Cocaine
Procaine
Benzocaine
Tetracaine
What local anesthetics belong to the Amide class?
Lidocaine
Mepivicaine
Bupivaciane
Ropivacaine
How are esters metabolized?
Pseudocholinesterase
How are amides metabolized?
Cytochrome p450
What is the only local anesthetic that causes vasoconstriction? Why?
Cocaine
Inhibits NE uptake and catecholamine
How is cocaine used?
Topically by ENT
What are signs of cocaine OD?
excitement
reslessness
confusion
tremor
What toxicity is caused by cocaine?
Cardiotoxic
What is the greatest vasodilator of all local anesthetics?
Procaine (Novocain)
What is cocaines onset and duration?
rapid onset
medium duration
What is Procaines potency, onset, & duration?
potency= low
onset= slow
duration= short
What local anesthetic has a high incidence of allergy?
Procaine
What local anesthetic has the greatest potential for systemic toxicity?
Tetracaine
What is tetracaine used for?
Spinal anesthesia
What is Tetracaine onset & duration?
onset= slow
duration= long
Why is Benzocaine used topically?
Poor solubility in water
Poor absorption
High toxicity if absorbed
