Nagelhout - Pharm 2 Exam 2 |
82 Accurate Q’s and A’s
Ester Local Anesthetics (5) - -- Cocaine
- Procaine
- Chloroprocaine
- Tetracaine
- Benzocaine
(only 1 "i" in the name)
- Amide Local Anesthetics (6) - -- Lidocaine
- Prilocaine
- Ropivicaine
- Bupivacaine
- Articaine
- Mepivicaine
(2 "i's" in the name)
- Miscellaneous drugs associated with Local Anesthetics - -- EMLA Cream
- Hyaluronidase
- Oraverse
- Three required chemical components of the local anesthetic molecule - -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 - -NH (positively charged) and
Carbonyl oxygen (negatively charged) = attracted to each other → difficult to
separate = difficult to metabolize
- Ester Intermediate bond characteristics - -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 - -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 - -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 - -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? - -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? - -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? - -1. No
2. No
- Local anesthetic mechanism of action (except Benzocaine) - -1. Inject local
anesthetic into tissue
2. Non-ionized form crosses the 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 - -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 - -1. Nerve blockade (non-
ionized)
2. Blood stream uptake & removal (absorption → drug wears off)
3. Non-specific tissue binding
82 Accurate Q’s and A’s
Ester Local Anesthetics (5) - -- Cocaine
- Procaine
- Chloroprocaine
- Tetracaine
- Benzocaine
(only 1 "i" in the name)
- Amide Local Anesthetics (6) - -- Lidocaine
- Prilocaine
- Ropivicaine
- Bupivacaine
- Articaine
- Mepivicaine
(2 "i's" in the name)
- Miscellaneous drugs associated with Local Anesthetics - -- EMLA Cream
- Hyaluronidase
- Oraverse
- Three required chemical components of the local anesthetic molecule - -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 - -NH (positively charged) and
Carbonyl oxygen (negatively charged) = attracted to each other → difficult to
separate = difficult to metabolize
- Ester Intermediate bond characteristics - -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 - -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 - -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 - -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? - -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? - -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? - -1. No
2. No
- Local anesthetic mechanism of action (except Benzocaine) - -1. Inject local
anesthetic into tissue
2. Non-ionized form crosses the 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 - -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 - -1. Nerve blockade (non-
ionized)
2. Blood stream uptake & removal (absorption → drug wears off)
3. Non-specific tissue binding
