Week 3 Local anesthetics

Question 1

Esters

Answer 1

only one I in name (procaine, Tetracaine); lipophilic agents are more potent and longer lasting

Question 2

Amides

Answer 2

2 I’s in name (Lidocaine, bupivacaine); lipophilic agents are more potent and longer lasting

Question 3

If drug has 2 a’s in name

Answer 3

Long lasting (amides & esters) (bupivacaine, tetracaine)

Question 4

MOA

Answer 4

open channel blockers of voltage-gated sodium channels; LOCAL ANESTHETICS-SODIUM CHANNELS!; block from the inside when channel is open; fibers w/ high firing frequency are blocked first (pain fibers); decrease AP propagation- nerve conduction fails

Question 5

MOA cont.- pH

Answer 5

effect dependent on pH; only uncharged base can cross the membrane- but must become charged intracellularly to block the channel on the inside

Question 6

Infected tissue effects MOA

Answer 6

pH will be lower than 7.4- less uncharged form available to cross the membrane- thus less Na2+ channels blocked

Question 7

Actions of local anesthetics on nerves

Answer 7

smaller fibers blocked more easily than larger fibers; myelinated fibers are blocked more easily than unmyelinated; pain sensations selectively blocked by local anesthetics; Adelta fibers most sensitive to blockade

Question 8

Order of blockade by local anesthetics

Answer 8

Pain (fibers have high firing rate & long APs); other sensations; motor