Exam 2 Local Anesthetics Flashcards
Order of Nerve blockade
Generally, smaller diameter fibers and those with less myelination are blocked first
1st= sympathetic, 2nd= pain
Exception: Brachial plexus block
Which fibers are associted with pain?
A-δ(delta) and C fibers
Structure activity of local anesthetics
All are weak bases –pK~7.7 –9
Potency, onset, and duration are affected by 3 things
1) pK -> low pK = faster onset
2) Protein binding -> high protein binding -> longer DOA
3) Lipid solubility -> high lipid solubility -> higher potency
Which amide drug has a fast onset and ONLY local anesthetic that may be given IV or used for intravenous regional anesthesia?
Lidocaine
Which amide drug has analgesic effect?
Lidocaine
Which amide drug has the HIGHEST cardiovascular toxicity?
Bupivacaine
Which amide drug is used for nerve block, intra-articular (common in large animal)?
Mepivacaine
Where is the fastest absorption site?
Fastest absorption with intercostal blocks
-Highest peak plasma concentration
Which ester drug has the fastest onset?
Procaine
____ should be used for epidurals and spinal anesthesia
Preservative-free versions
With ____, first sign is cardiovascular collapse -> death
Bupivacaine
Spinal ______ seems to be the worst neurotoxicity
Spinal Lidocaine
_____ used for equine lameness diagnosis IA
Mepivacaine
What to avoid when treatment of arrest secondary to LA?
Avoid lidocaine, Ca-channel blockers, Beta blockers, vasopressin
