Local Anesthesia

Question 1

3 parts of local anesthesia

Answer 1

aromatic group
intermediate linkage
amine group

Question 2

aromatic group

Answer 2

lipophilic properties

Question 3

intermediate linkage

Answer 3

spacial separation between lipophilic and hydrophilic ends

connects them with ester or amide

Question 4

amine group

Answer 4

affects pKa and speed of onset

Question 5

difference between amide and ester

Answer 5

amide - union of carboxylic acid and amine (peptide bond is amide)

ester -union of carboxylic acid and alcohol

Question 6

except for procaine, all injectable dental locals are (amines or esters)

Answer 6

amines

Question 7

topicals are mostly (amines or esters)

Answer 7

esters

Question 8

the amine portion is the ____

Answer 8

base

Question 9

what is special about free bases?

Answer 9

the amine portion is a free base

only free bases can cross the cell membranes, so onset of action is faster for lower pKa’s (stronger acids) because they give up their protons more easily and become uncharged “free bases”

Question 10

onset is faster for ____

Answer 10

low pKa’s (strong acids)

Question 11

acidic environments like inflamed tissue…

Answer 11

have slow onset, since the base remains protonated in the low pH environment (impedes local anesthesia development)

Question 12

locals stabilize ________

Answer 12

membranes

decrease rate of depolarization and repolarization

Question 13

locals prevent _____

Answer 13

rapid sodium influx

needed to make an AP

Question 14

why are the pharmacokinetics of locals unique?

Answer 14

they become ineffective when absorbed into the system / blood stream

Question 15

local anesthetics wear off when…

Answer 15

redistributed throughout the body to all tissues (when the numbness goes away)

Question 16

metabolic half life is not related to _________ but is related to ______

Answer 16

duration of anesthesia
toxicity

Question 17

why does metabolism affect overall toxicity?

Answer 17

because it’s balance between rates of absorption at injection site and rate of removal from the blood

Question 18

duration of action is related to _____ (not _______)

Answer 18

protein bonding of local

metabolic transformation

Question 19

locals are all (vasoconstrictors or vasodilators)

Answer 19

vasodilators

Question 20

which local anesthetic is not a vasodilator? (exception!)

Answer 20

cocaine!

Question 21

what is needed in locals to slow the distribution?

Answer 21

vasoconstrictors

Question 22

_____ anesthesia takes the longest to develop (and leaves first)

Answer 22

pulpal

Question 23

which type of anesthesia lasts longest? Nerve blocks or infiltration?

Answer 23

nerve blocks

Question 24

primary site of metabolism for amides

Answer 24

liver

Question 25

excretion of LA

Answer 25

kidney for LA agents and metabolites

Question 26

when do local anesthetics lose their effect?

Answer 26

when they are absorbed into the bloodstream

Question 27

rate at which local is removed from the plasma is expressed as its

Answer 27

metabolic half life

Question 28

duration of action of local anesthetics (shortest to longest) in terms of type of tissue

Answer 28

shortest = pulpal anesthesia longest = soft tissue anesthesia

Question 29

duration of action of local anesthetics (shortest to longest) in terms of type of LA

Answer 29

carbocaine (mepivacaine) xylocaine (lidocaine) septocaine (articaine) marcaine (bupivacaine)

Question 30

which anesthetic is not recommended in pedo or in cognitiviely impaired adults?

Answer 30

marcaine (bupivacaine)

Question 31

methamoglobin

Answer 31

hemoglobin in which the iron ion has been oxidized to the ferric instead of the ferrous state does not bind O2

Question 32

methamoglobin is produced by which local

Answer 32

articaine / prilocaine

Question 33

max does for lidocaine with epi

Answer 33

4.4 mg / kg per malamed

Question 34

max dose for mepivacaine

Answer 34

4.4 mg / kg

Question 35

max dose for bupivicaine

Answer 35

1.3 mg / kg

Question 36

max dose for septocaine

Answer 36

7mg / kg

Question 37

epinephrine max recommended dose for non-cardiac patient

Answer 37

0.2 mg

Question 38

epinephrine max recommended dose for cardiac patient

Answer 38

0.04 mg

Question 39

lidocaine 2% has 34 mg of local in carpule. what is do