Nagelhout Exam 5- Local Anesthetics and
Autonomic Questions and Well Verified Answers
What are the two classes of local anesthetics? - ANSWER-esters and amides
What is an easy way to tell what class a LA is? - ANSWER-Esters have one "i" in their
name and amides have 2 "i"'s
(Tetracaine vs prilocaine)
Name the 5 ester LAs - ANSWER-Cocaine
Procaine
Chloroprocaine
Tetracaine
Benzocaine
Name the 6 amide LAs - ANSWER-Lidocaine
Prilocaine
Ropivacaine
Bupivacaine
Articaine
Mepivacaine
What is the general structure of a local anesthetic molecule? (3 things) - ANSWER-1) a
lipophilic benzene ring
2) An ester or amide linkage (intermediate chain)
3) A hydrophilic quaternary amine
What is an ester vs amide linkage composed of? - ANSWER-Ester: O==C-----O
Amide: NH----C==O
How are esters metabolized? - ANSWER-catalyzed by plasma and tissue
cholinesterase via hydrolysis
Is ester metabolism fast or slow? - ANSWER-rapid and occurs throughout the body
How are amides metabolized? - ANSWER-in the liver by CYP1A2 and CYP3A4
Is metabolism of amides fast or slow? - ANSWER-slower bc they require transport to
the liver
Which type of LA has a higher allergy potential? - ANSWER-esters
If a patient has an allergy to an ester drug, can they be given a different ester? -
ANSWER-No, if patients exhibit an allergy to any ester drug, all other esters should be
avoided
,Is there cross allergy among the amide class? What about between ester and amide
agents? - ANSWER-No and no
Are esters short or long acting? - ANSWER-shorter acting due to ready metabolism
What is the longest acting ester? - ANSWER-Tetracaine
Are amides short or long acting? - ANSWER-Longer acting; more lipophilic and protein
bound and require transport to the liver for metabolism
Which type of LA is more prone to toxicity? - ANSWER-Amides
Absorption of a LA equals ________ - ANSWER-wearing off
(don't want them to be absorbed, you want them to stay locally as long as possible)
LAs have the ability to _______ or not - ANSWER-ionize
What portion of the LA enters the nerve? - ANSWER-the nonionized portion
Nonionized is the same as? - ANSWER-lipid soluble
Once inside the axoplasm, the drug ________ - ANSWER-reequilibrates
What does the ionized fraction of LA do in the axoplasm? - ANSWER-attaches to the
local anesthetic receptor on the inside of the sodium channel
LAs block ________ - ANSWER-sodium channels
Describe the overall process of how a LA works - ANSWER-Outside of the nerve, there
is equilibrium between the ionized and non-ionized portions of the drug. The nonionized
portion passes through the lipid membrane of the nerve, and once inside the axoplasm,
the drug requilibrates and "re-ionizes". The ionized portion attaches to the LA receptor
on the inside of the sodium channel
LAs block _________ in excitable cells, which decreases the likelihood of _________ -
ANSWER-voltage-dependent Na+ channels;
an action potential
The target site of LAs is on the ___________ - ANSWER-cytoplasmic side of the
neuron membrane
Ionized form = - ANSWER-hydrophilic (water-soluble)
Esters are metabolized by________ - ANSWER-plasma cholinesterases
The pKa of a LA is directly proportional to _______ - ANSWER-onset
, The lower the pKa and the closer it is to 7.4, the ________ its onset - ANSWER-faster
What is the exception to the pKa rule of onset? - ANSWER-Chloroprocaine: it has the
fastest onset, but its pKa is 8.7--due to high concentration usually given
What are two of the fastest onset LAs? - ANSWER-Mepivacaine (7.6) and Etidocaine
(7.7)
The lower the pKa, the faster the _______ - ANSWER-onset
The percent of protein binding of a LA correlates to what? - ANSWER-its duration of
action
The higher protein binding drugs have a ______ duration of action - ANSWER-longer
What are some of the long acting LAs? - ANSWER-Bupivacaine (95)
Etidocaine (94)
Ropivacaine (94)
What does the addition of epinephrine do to the onset time of a LA? - ANSWER-
decreases it (except during spinal anesthesia--> slows the onset time)
What does increasing the dose (concentration or volume) do to the onset time of a LA?
- ANSWER-decreases it
What does addition of epinephrine do to the degree of motor blockade of a LA? -
ANSWER-increases it
What does increasing the dose do for the degree of motor blockade of a LA? -
ANSWER-increases it
What does the addition of epinephrine do for the degree of sensory blockade of a LA? -
ANSWER-increases it
What does increasing the dose do for the degree of sensory blockade of a LA? -
ANSWER-increases it
What does addition of epinephrine or increasing the dose do for the duration of a
blockade? - ANSWER-increases it
What does addition of epinephrine or increasing the dose do for the area of blockade? -
ANSWER-increases it
What does increasing the dose do for the peak plasma concentration of a drug? -
ANSWER-increases it
Autonomic Questions and Well Verified Answers
What are the two classes of local anesthetics? - ANSWER-esters and amides
What is an easy way to tell what class a LA is? - ANSWER-Esters have one "i" in their
name and amides have 2 "i"'s
(Tetracaine vs prilocaine)
Name the 5 ester LAs - ANSWER-Cocaine
Procaine
Chloroprocaine
Tetracaine
Benzocaine
Name the 6 amide LAs - ANSWER-Lidocaine
Prilocaine
Ropivacaine
Bupivacaine
Articaine
Mepivacaine
What is the general structure of a local anesthetic molecule? (3 things) - ANSWER-1) a
lipophilic benzene ring
2) An ester or amide linkage (intermediate chain)
3) A hydrophilic quaternary amine
What is an ester vs amide linkage composed of? - ANSWER-Ester: O==C-----O
Amide: NH----C==O
How are esters metabolized? - ANSWER-catalyzed by plasma and tissue
cholinesterase via hydrolysis
Is ester metabolism fast or slow? - ANSWER-rapid and occurs throughout the body
How are amides metabolized? - ANSWER-in the liver by CYP1A2 and CYP3A4
Is metabolism of amides fast or slow? - ANSWER-slower bc they require transport to
the liver
Which type of LA has a higher allergy potential? - ANSWER-esters
If a patient has an allergy to an ester drug, can they be given a different ester? -
ANSWER-No, if patients exhibit an allergy to any ester drug, all other esters should be
avoided
,Is there cross allergy among the amide class? What about between ester and amide
agents? - ANSWER-No and no
Are esters short or long acting? - ANSWER-shorter acting due to ready metabolism
What is the longest acting ester? - ANSWER-Tetracaine
Are amides short or long acting? - ANSWER-Longer acting; more lipophilic and protein
bound and require transport to the liver for metabolism
Which type of LA is more prone to toxicity? - ANSWER-Amides
Absorption of a LA equals ________ - ANSWER-wearing off
(don't want them to be absorbed, you want them to stay locally as long as possible)
LAs have the ability to _______ or not - ANSWER-ionize
What portion of the LA enters the nerve? - ANSWER-the nonionized portion
Nonionized is the same as? - ANSWER-lipid soluble
Once inside the axoplasm, the drug ________ - ANSWER-reequilibrates
What does the ionized fraction of LA do in the axoplasm? - ANSWER-attaches to the
local anesthetic receptor on the inside of the sodium channel
LAs block ________ - ANSWER-sodium channels
Describe the overall process of how a LA works - ANSWER-Outside of the nerve, there
is equilibrium between the ionized and non-ionized portions of the drug. The nonionized
portion passes through the lipid membrane of the nerve, and once inside the axoplasm,
the drug requilibrates and "re-ionizes". The ionized portion attaches to the LA receptor
on the inside of the sodium channel
LAs block _________ in excitable cells, which decreases the likelihood of _________ -
ANSWER-voltage-dependent Na+ channels;
an action potential
The target site of LAs is on the ___________ - ANSWER-cytoplasmic side of the
neuron membrane
Ionized form = - ANSWER-hydrophilic (water-soluble)
Esters are metabolized by________ - ANSWER-plasma cholinesterases
The pKa of a LA is directly proportional to _______ - ANSWER-onset
, The lower the pKa and the closer it is to 7.4, the ________ its onset - ANSWER-faster
What is the exception to the pKa rule of onset? - ANSWER-Chloroprocaine: it has the
fastest onset, but its pKa is 8.7--due to high concentration usually given
What are two of the fastest onset LAs? - ANSWER-Mepivacaine (7.6) and Etidocaine
(7.7)
The lower the pKa, the faster the _______ - ANSWER-onset
The percent of protein binding of a LA correlates to what? - ANSWER-its duration of
action
The higher protein binding drugs have a ______ duration of action - ANSWER-longer
What are some of the long acting LAs? - ANSWER-Bupivacaine (95)
Etidocaine (94)
Ropivacaine (94)
What does the addition of epinephrine do to the onset time of a LA? - ANSWER-
decreases it (except during spinal anesthesia--> slows the onset time)
What does increasing the dose (concentration or volume) do to the onset time of a LA?
- ANSWER-decreases it
What does addition of epinephrine do to the degree of motor blockade of a LA? -
ANSWER-increases it
What does increasing the dose do for the degree of motor blockade of a LA? -
ANSWER-increases it
What does the addition of epinephrine do for the degree of sensory blockade of a LA? -
ANSWER-increases it
What does increasing the dose do for the degree of sensory blockade of a LA? -
ANSWER-increases it
What does addition of epinephrine or increasing the dose do for the duration of a
blockade? - ANSWER-increases it
What does addition of epinephrine or increasing the dose do for the area of blockade? -
ANSWER-increases it
What does increasing the dose do for the peak plasma concentration of a drug? -
ANSWER-increases it
