Local Anesthetics Flashcards
Which anesthetics are esters? 1 i
Procaine
Tetracaine
Benzocaine
Cocaine
Which anesthetics are amides? 2 i’s
Lidocaine
Mepivacaine
Bupivacaine
Ropivacaine
Rank from most potent to least (ester anesthetic)
tetracaine >cocaine>procaine
long med short duration of action
Rank from most potent to least (amides anesthetic)
Ropivacaine or Bupivacaine >lidocaine>mepivacaine
long medium
What is MOA of local anesthetics?
blocks the Na channels of excitable membranes
blocks conduction of the AP
T/F Sodium bicarbonate may accelerate the action of local anesthetics
TRUE-sodium bicarbonate changes the pH and allows anesthetic to bind
T/F Non charged form passes through the lipohilic membrane
true
T/F The slightly acidic pH within the extra vascular space causes the non charged weakly basic anesthetic to become protanated (charged) and active
TRUE
T/F Addition of epineprhrine to short acting anesthetics prolongs duration
TRUE
How are ester anesthetics metabolized?
plasma cholinesterase-very rapid
Procaine>cocaine>tetracaine (slowest)
How are amide anesthetics metabolized?
liver
lidocaine> bupivacaine>ropivacaine (slowest)
T/F Small fibers are blocked more easily than larger fibers
TRUE
T/F myelinated fibers are blocked more easily than unmyelinated fibers
TRUE
Explain signaling info to CNS for each fiber? A-D A-B A-A C-fibers
A-D: temp and pain
A-B: touch
A-A: propioception
C fibers: pain, temp, itch
Which fibers are more sensitized by anesthetics?
In order of most sensitized to least:
Type B-preganglionic autonomic fibers -light myelination
Type C: post ganglionic or pain-no myelination
Type A delta most sensitive in A group-heavy myleination
