Pharmacology - Test 2 Local Anesth (Spring 11)

Front 1

What is the mechanism of action of all local anesthetics?

Back 1

Block voltage-gated sodium channels

Front 2

Most local anesthetics are weak (acids/bases)

Back 2

weak bases

Front 3

Which form, charged or uncharged, is most active in terms of channel binding?

Back 3

charged

Front 4

Which form, charged or uncharged, is able to penetrate biologic membranes

Back 4

uncharged

Front 5

At what location about the channel must the local anesthetic bind?

Back 5

drug must bind within channel

Front 6

pH is (lower/higher) at sites of infection

Back 6

lower (more H+ = more charged drugs)

Front 7

Local anesthetics can be administered with CO2 to rapidly (acidify/basicify) the (inside/outside) of the cell

Back 7

CO2 rapidly acidifies (more H+) the inside of cells (increase amount of drug ionized on inside)

Front 8

As H+ concentration WITHIN a cell rises, local anesthetics become (more/less) effective

Back 8

more

Front 9

True or False - For direct injection, absorption and distribution are not relevant issues for determining rate of onset

Back 9

True

Front 10

True or False - For direct injection, absorption does not matter for duration and specificity of the effect

Back 10

False

Front 11

What can be co-administered with local anesthetics to prevent distribution away from the site

Back 11

Epinephrine

Front 12

Co-administering epinephrine with local anesthetics facilitates uptake of the anesthetic into what types of cells?

Back 12

Neuronal

Front 13

True or False - Cocaine is its own vasoconstrictor

Back 13

True

Front 14

What functional groups can local anesthetics be classified by?

Back 14

esters, amides

Front 15

Which functional group of anesthetics is hydrolyzed rapidly in the blood?

Back 15

esters

Front 16

Which functional group of anesthetics is hydrolyzed by the liver P450s? (amides/esters)

Back 16

amides

Front 17

What are the three (3) states of voltage-gated sodium channels?

Back 17

resting, open, inactive

Front 18

What is the resting membrane potential for sodium channels?

Back 18

-70 mV

Front 19

Sodium channels begin to inactivate as __________ channels begin to open

Back 19

potassium

Front 20

Which state (resting, open, closed) has the highest affinity for anesthetics?

Back 20

open

Front 21

Anesthetic binding is most effective on (rapidly/slowly) firing neurons

Back 21

rapidly

Front 22

Which subunit of the sodium channel is the target for local anesthetics?

Back 22

alpha subunit

Front 23

True or False - Local anesthetics can block motor nerves

Back 23

True

Front 24

What size nerve fibers are affected first by local anesthetics?
(small/large)

Back 24

small diameter fibers are the first to be inhibited

Front 25

What effect does myelination have on local anesthetics?

Back 25

myelinated fibers are inhibited more easily than unmyelinated fibers of the same diameter

Front 26

Which are more sensitive to local anesthetics?
(pain/motor)

Back 26

pain fibers are more sensitive than motor fibers

Front 27

In general, what class of local anesthetics are short-acting?

Back 27

esters - procaine, chloroprocaine

Front 28

In general, what class of local anesthetics are intermediate- to long-acting?

Back 28

amides

Front 29

What are the intermediate-acting local anesthetics? (3)

Back 29

LiMP
lidocaine, mepivacaine, prilocaine

Front 30

What are the long-acting local anesthetics? (5)

Back 30

TREBL
tetracaine, ropivacaine, etidocaine, bupivocaine, levobupivocaine

Front 31

What is the relationship between lipid-solubility and potency of local anesthetics?

Back 31

lipid-solubility correlates with higher potency

Front 32

Epidural administration of which local anesthetic is associated with cardiac arrest and death?
(removed from epidurals)

Back 32

Bupivacaine

Front 33

What local anesthetics can be used for neuropathic pain? (3)

Back 33

mexiletine, tocainide, lidocaine

Front 34

Local anesthetics used for neuropathic pain are often an adjuvant to what combination of drug classes?

Back 34

antidepressant/anticonvulsant

Front 35

What is the preferred local anesthetic for nose/throat surgery?

Back 35

cocaine
lidocaine/epinephrine combination
(also tetracaine, benzocaine)

Front 36

What types of tissues should be avoided when giving local anesthetics in the CNS?

Back 36

highly perfused tissues

Front 37

What are early warning signs of toxicity from local anesthetics in the CNS? (2)

Back 37

tongue numbness, metallic taste

Front 38

What drug class is given prior to large doses of local anesthetics in the CNS in order to prevent seizures?

Back 38

benzodiazepines

Front 39

What can you use to treat seizures caused by local anesthetics in the CNS?

Back 39

IV thiopental (barbiturate), midazolam or diazepam (benzos)

Front 40

True or False - All local anesthetics are neurotoxic in spinal applications

Back 40

True

Front 41

Which drugs are especially neurotoxic in spinal applications? (2)

Back 41

chloroprocaine, lidocaine

Front 42

True or False - Neurotoxicity from local anesthetics is directly related to their actions on sodium channels

Back 42

False - may have to do with axonal transport

Front 43

Which drug has a metabolite that converts hemoglobin to methemoglobin?

Back 43

Prilocaine

Front 44

What class of local anesthetics causes allergic reactions? (esters/amides)

Back 44

ester-type anesthetics
(no real reactions to amides)

Front 45

True or False - Local anesthetics block cardiac sodium channels

Back 45

True

Front 46

What effect do local anesthetics have on the heart?

Back 46

abnormal pacemaker activity

Front 47

All local anesthetics (except cocaine) cause arteriolar (dilation/constriction) and (stimulate/depress) cardiac contraction leading to (hypotension/hypertension)

Back 47

arteriolar dilation
depress cardiac contraction
hypotension

Front 48

Which local anesthetic is most highly cardiotoxic?

Back 48

bupivacaine

Front 49

True or False - Cocaine may cause arrhythmias

Back 49

True