pharm- local anesthetics

Question 1

medication that causes reversible absence of pain sensation but must be delivered to target organ

Answer 1

local anesthetics

Question 2

how do local anesthetics work

Answer 2

block voltage gated sodium channels

interrupting initiation and propagation of nerve impulses in axons

Question 3

two classes of local anesthetics

Answer 3

aminoesters and aminoamides

Question 4

intrinsic potency and duration of action are clearly dependent on certain features of the ______

Answer 4

molecule

Question 5

local anesthetic medication molecule usually contains either an _____ or ____

Which is shorter action?

Answer 5

ester or an amide

ester shorter action because more prone to hydrolysis

Question 6

How do you differentiate amino ester linkage of amino amide linkage drugs?

Answer 6

amino ester= One I EX: procaine, tetrocaine, cocaine

amino amide = two I E
EX: lidocaine, mepivacaine

Question 7

local anesthetics are less effective in _______ due to low pH favors the charged form : so less diffusion across the membrane

Answer 7

infected tissue

Question 8

absorption of local anesthetics is determined by?

Answer 8

dosage, site of injection, drug-tissue binding, local tissue blood flow use of vasoconstictor and drug itself

Question 9

___________ decrease rate of system pic absorption and decrease systematic toxicity, increase local drug concentration and increase neuronal uptake, and increase local duration of action

Answer 9

vasoconstrictors

Question 10

with the exception of cocaine, all local anesthetics are ?

Answer 10

vasodilators

Question 11

metabolism of amino ester?

Answer 11

hydrolysis by plasma esterases

Question 12

metabolism of amino amides?

Answer 12

hepatic microsomal enzymes (p450)

liver disease or decreased hepatic blood flow can decrease the rate of metabolism of lidocaine

Question 13

what is a common additive to local anesthetics?

Answer 13

epinephrine usually 5 microgram/ml

Others: alpha 2 agonist clonidine and dexamthasone

Question 14

what are the disadvantages of using additives with local anesthetics?

Answer 14

may contribute to cardiac dysrythmias

may accentuate systemic hypertension

Question 15

excessive plasma concentrations of local anesthetics causes systemic toxicity this could be due to ?

Answer 15

accidental intravascular injection –> peripheral nerve blocks

absorption –> tissue injection sites

Question 16

systemic absorption of local anesthetics is greatest when?

Answer 16

after intercostal nerve blocks and caudal anesthesia

med after epidural anesthesia

low brachial plexus blocks

Question 17

signs and symptoms of CNS toxicity

Answer 17

numbness around mouth, face tingling, restlessness, vertigo, tinnitus, slurred speech, seizures

seizures are followed by coma or death

Question 18

what is treatment for CNS toxicity?

Answer 18

O2, ventilation, benzodiazepines (to stop seizures) , propofol

Question 19

what drug is most likely to cause cardiac toxicity?

Answer 19

bupivacaine

Question 20

what is the standard treatment for Local anesthetic systemic toxicity (LAST)

Answer 20

lipid resuscitation

Question 21

what class of local anesthetic is most prone to allergic reactions

Answer 21

amino ester> amino amides

Question 22

earliest injectable local anesthetic, primarily as spinal anesthetic

Answer 22

procaine

Amino ester

Question 23

non stable and potential for hypersensitivity reactions –> limited use after the introduction of lidocaine

Answer 23

procaine

Question 24

commonly used spinal anesthesia/ long action if used with vasoconstrictor (but high risk of transient neurological symptoms)

Answer 24

tetracaine

Question 25

rarely used for epidural or peripheral nerve blocks because slow onset and profound motor blockade and potential toxicity at high dosing

Answer 25

tetracaine

Question 26

was popular as epidural because of rapid hydrolysis caused no concern about systemic toxicity and fetal exposure no toxicity found in studies

Answer 26

chloroprocaine

Question 27

neurotoxic injury tempered enthusiasm: accidental intrathecal injection of large doses intended for the epidural space

Answer 27

chloroprocaine

Question 28

off label use for spinal anesthesia - no more than 60 mg

Answer 28

chloroprocaine

Question 29

most widely used local anesthetic effective by all routes,

Answer 29

lidocaine (xylocaine)

Question 30

faster onset, longer lasting, good alternative for those allergic to ester type, more potent than procaine but equal toxicity more sedative than others

Answer 30

lidocaine (xylocaine)

Question 31

1/3 patients have transient neurological symptoms within the first 12 - 24 hours after surgery: severe pain and dysesthesia self limited 3 days to week treat with NSAIDS

Answer 31

lidocaine (xylocaine)

Question 32

most commonly used local anesthetic for epidural

Answer 32

bupivacaine (marcaine)

Question 33

high quality sensory anesthesia relative to motor blockade/ peripheral nerve block/ unblemished record as spinal anesthetic/ more cardiotoxic thank other LA

Answer 33

bupivacaine (marcaine)

Question 34

bupivacaine accidentally injected intravenously during attempted epidural anesthesia causes

Answer 34

refractory cardiac arrest

Question 35

fast in slow out local anesthetic

Answer 35

bupivacaine (marcaine)

Question 36

enantiomer of bupivacaine less potent

Answer 36

ropivacaine

Question 37

more favorable interaction with cardiac sodium ion channels --> reduced cardiotoxicity/ motor blockade is less pronounced

Answer 37

ropivacaine