NAGELHOUT - PHARM EXAM 2
QUESTIONS AND ANSWERS 100%
CORRECT
Ester Local Anesthetics (5) - ANSWER-- Cocaine
- Procaine
- Chloroprocaine
- Tetracaine
- Benzocaine
(only 1 "i" in the name)
Amide Local Anesthetics (6) - ANSWER-- Lidocaine
- Prilocaine
- Ropivicaine
- Bupivacaine
- Articaine
- Mepivicaine
(2 "i's" in the name)
Miscellaneous drugs associated with Local Anesthetics - ANSWER-- EMLA Cream
- Hyaluronidase
- Oraverse
Oraverse - ANSWER-Rigatine: causes vasodilation that results faster recovery from LA
in dental procedures (reversal of the epi effects)
Three required chemical components of the local anesthetic molecule - ANSWER-1.
Lipophilic portion (Benzene ring)
2. Hydrophilic portion (Quarternary amine)
3. Separated by an Intermediate Chain (either an Ester or Amide chain)
Amide Intermediate bond characteristics - ANSWER-NH (positively charged) and
Carbonyl oxygen (negatively charged) = attracted to each other → difficult to separate =
difficult to metabolize
Ester Intermediate bond characteristics - ANSWER-Oxygen (negatively charged) and
Carbonyl oxygen (negatively charged) = repel each other → open bond = easy to
metabolize
All local anesthetics take on these 2 forms to be non-ionized or ionized depending on
the pH - ANSWER-1. Quarternary amine (charged nitrogen group) → water soluble
2. Tertiary Amine (non-charged nitrogen group) → lipid soluble
,Ester metabolism
1. Metabolized by
2. Metabolized in
3. Fast or slow metabolism
4. Duration of action
5. Longest acting Ester - ANSWER-1. (Location specific) Esterases
2. Everywhere
3. Fast
4. Short
5. Tetracaine
Amide metabolism
1. Metabolized by
2. Metabolized in
3. Fast or slow metabolism
4. Duration of action
5. Risk with Amide local anesthetic metabolism - ANSWER-1. Liver enzymes (CYP1A2
and CYP3A4)
2. Liver
3. Slow
4. Long: highly protein bound and liver metabolism
5. Rapid absorption can lead to significant blood level → toxicity
Which local anesthetic type has a higher allergy probability? - ANSWER-Esters
1. If a patient is allergic to an ester local anesthetic, are they allergic to all other ester
anesthetics?
2. Are they allergic to the amides? - ANSWER-1. Yes
2. No
1. If a patient is allergic to an amide local anesthetic, are they allergic to all other amide
anesthetics?
2. Are they allergic to the esters? - ANSWER-1. No
2. No
Local anesthetic mechanism of action (except Benzocaine) - ANSWER-1. Inject local
anesthetic into tissue
2. Non-ionized form crosses the cell membrane
3. In new pH of the cytoplasm, some of the non-ionized LA becomes ionized
4. Ionized LA enters the sodium channel and blocks sodium influx
Benzocaine mechanism of action - ANSWER-1. Inject local anesthetic into tissue
2. Ionized form of the drug enters the sodium channel of the neuron and blocks sodium
influx
, Injected Local Anesthetic goes to these 3 places - ANSWER-1. Nerve blockade (non-
ionized)
2. Blood stream uptake & removal (absorption → drug wears off)
3. Non-specific tissue binding
Local anesthetic in blood stream goes to these 2 places - ANSWER-1. Systemic tissue
distribution
2. Liver (Amide) or Plasma Hydrolysis (Ester)
Amide local anesthetics excreted by - ANSWER-Kidney
The lower the pKa (closer to 7.4), the ____ the onset of the local anesthetic (except
____) - ANSWER-Faster
Chloroprocaine (higher pH but fastest onset)
The higher the protein binding, the ___ the duration - ANSWER-Longer
Local anesthetics greater than 90% protein bound (5) - ANSWER-- Etidocaine (94%)
- Ropivicaine (94%)
- Tetracaine (94%)
- Bupivicaine (95%)
- Cocaine (98%)
Ion trapping with Local Anesthetics - ANSWER-A basic drug in the brain → patient has
seizure → becomes more acidic due to hypoxia → basic drug in a more acidic
environment = more ionized drug = unable to cross membrane and stays in the brain →
prolonged toxicity
Fetal circulation and Local Anesthetics - ANSWER-Fetal circulation is more acidotic that
maternal → non-ionized local anesthetic able to cross placental barrier → acidotic fetal
circulation = LA more ionized and unable to cross out of placental barrier → stays in
fetal circulation (ion trapping)
Can local anesthetics be used in infected tissues? - ANSWER-No:
Acidotic environment of infected tissue = 100% ionized LA (unable to cross neuron
membrane)
Adding sodium bicarb to local anesthetic solution does what? - ANSWER-Increases pH
of solution → increases concentration of non-ionized form of LA → crosses neuron
membrane more readily
Carbonation of local anesthetic solution does what? (How) - ANSWER-- Speeds onset
and intensity of blockade
- CO2 diffuses into the nerve → LA (basic drug) enters the nerve and is more ionized
(more acidic environment due to CO2) → more ionized form of drug available to block
sodium channel
QUESTIONS AND ANSWERS 100%
CORRECT
Ester Local Anesthetics (5) - ANSWER-- Cocaine
- Procaine
- Chloroprocaine
- Tetracaine
- Benzocaine
(only 1 "i" in the name)
Amide Local Anesthetics (6) - ANSWER-- Lidocaine
- Prilocaine
- Ropivicaine
- Bupivacaine
- Articaine
- Mepivicaine
(2 "i's" in the name)
Miscellaneous drugs associated with Local Anesthetics - ANSWER-- EMLA Cream
- Hyaluronidase
- Oraverse
Oraverse - ANSWER-Rigatine: causes vasodilation that results faster recovery from LA
in dental procedures (reversal of the epi effects)
Three required chemical components of the local anesthetic molecule - ANSWER-1.
Lipophilic portion (Benzene ring)
2. Hydrophilic portion (Quarternary amine)
3. Separated by an Intermediate Chain (either an Ester or Amide chain)
Amide Intermediate bond characteristics - ANSWER-NH (positively charged) and
Carbonyl oxygen (negatively charged) = attracted to each other → difficult to separate =
difficult to metabolize
Ester Intermediate bond characteristics - ANSWER-Oxygen (negatively charged) and
Carbonyl oxygen (negatively charged) = repel each other → open bond = easy to
metabolize
All local anesthetics take on these 2 forms to be non-ionized or ionized depending on
the pH - ANSWER-1. Quarternary amine (charged nitrogen group) → water soluble
2. Tertiary Amine (non-charged nitrogen group) → lipid soluble
,Ester metabolism
1. Metabolized by
2. Metabolized in
3. Fast or slow metabolism
4. Duration of action
5. Longest acting Ester - ANSWER-1. (Location specific) Esterases
2. Everywhere
3. Fast
4. Short
5. Tetracaine
Amide metabolism
1. Metabolized by
2. Metabolized in
3. Fast or slow metabolism
4. Duration of action
5. Risk with Amide local anesthetic metabolism - ANSWER-1. Liver enzymes (CYP1A2
and CYP3A4)
2. Liver
3. Slow
4. Long: highly protein bound and liver metabolism
5. Rapid absorption can lead to significant blood level → toxicity
Which local anesthetic type has a higher allergy probability? - ANSWER-Esters
1. If a patient is allergic to an ester local anesthetic, are they allergic to all other ester
anesthetics?
2. Are they allergic to the amides? - ANSWER-1. Yes
2. No
1. If a patient is allergic to an amide local anesthetic, are they allergic to all other amide
anesthetics?
2. Are they allergic to the esters? - ANSWER-1. No
2. No
Local anesthetic mechanism of action (except Benzocaine) - ANSWER-1. Inject local
anesthetic into tissue
2. Non-ionized form crosses the cell membrane
3. In new pH of the cytoplasm, some of the non-ionized LA becomes ionized
4. Ionized LA enters the sodium channel and blocks sodium influx
Benzocaine mechanism of action - ANSWER-1. Inject local anesthetic into tissue
2. Ionized form of the drug enters the sodium channel of the neuron and blocks sodium
influx
, Injected Local Anesthetic goes to these 3 places - ANSWER-1. Nerve blockade (non-
ionized)
2. Blood stream uptake & removal (absorption → drug wears off)
3. Non-specific tissue binding
Local anesthetic in blood stream goes to these 2 places - ANSWER-1. Systemic tissue
distribution
2. Liver (Amide) or Plasma Hydrolysis (Ester)
Amide local anesthetics excreted by - ANSWER-Kidney
The lower the pKa (closer to 7.4), the ____ the onset of the local anesthetic (except
____) - ANSWER-Faster
Chloroprocaine (higher pH but fastest onset)
The higher the protein binding, the ___ the duration - ANSWER-Longer
Local anesthetics greater than 90% protein bound (5) - ANSWER-- Etidocaine (94%)
- Ropivicaine (94%)
- Tetracaine (94%)
- Bupivicaine (95%)
- Cocaine (98%)
Ion trapping with Local Anesthetics - ANSWER-A basic drug in the brain → patient has
seizure → becomes more acidic due to hypoxia → basic drug in a more acidic
environment = more ionized drug = unable to cross membrane and stays in the brain →
prolonged toxicity
Fetal circulation and Local Anesthetics - ANSWER-Fetal circulation is more acidotic that
maternal → non-ionized local anesthetic able to cross placental barrier → acidotic fetal
circulation = LA more ionized and unable to cross out of placental barrier → stays in
fetal circulation (ion trapping)
Can local anesthetics be used in infected tissues? - ANSWER-No:
Acidotic environment of infected tissue = 100% ionized LA (unable to cross neuron
membrane)
Adding sodium bicarb to local anesthetic solution does what? - ANSWER-Increases pH
of solution → increases concentration of non-ionized form of LA → crosses neuron
membrane more readily
Carbonation of local anesthetic solution does what? (How) - ANSWER-- Speeds onset
and intensity of blockade
- CO2 diffuses into the nerve → LA (basic drug) enters the nerve and is more ionized
(more acidic environment due to CO2) → more ionized form of drug available to block
sodium channel
