Local Anesthetics: Question Set #1

Racemates (50:50 mixture of enantiomers):
1. ropivacaine (Naropin)
2. mepivacaine (Carbocaine)
3. bupivacaine (Marcaine)
4. B & C
5. A, B & C
Local anesthetics types: shorter duration of action
1. Ester-type agents
2. Amide-type agents
3. no difference in duration of action
Local anesthetics: acid/base properties
1. Local anesthetics are weak acids
2. Local anesthetics are weak bases
3. Local anesthetics have no ionizable groups
pKa range for most local anesthetics
1. 6.0-7.0
2. 7.0-8.0
3. 8.0-9.0
4. > 9.0
Influence on tissue infection on pH, compared to normal physiological pH.
1. Extracellular pH in infected tissue is higher
2. Extracellular pH in infected tissue is lower
3. about the same
Effectiveness of local anesthetics when injected into infected tissue:
1. greater effect (greater anesthesia)
2. reduced effect (reduced anesthesia)
3. no difference
Localization of local anesthetic receptor relative to the cell membrane:
1. the receptor is localized on the external cell membrane surface
2. the receptor is localized on the internal membrane surface
3. the receptor is a nuclear receptor (located near the nucleolus)
Pharmacokinetic characteristic of local anesthetics which favor more rapid onset of action:
1. pK farther away from physiological pH
2. pK close to physiological pH
Greatest vasodilation:
1. lidocaine (Xylocaine)
2. mepivacaine (Carbocaine)
3. equal
Effect of local anesthetic-mediated vasodilation on pharmacokinetic characteristics:
1. Greater vasodilation -- longer duration of action; reduced systemic absorption
2. Greater vasodilation -- increased systemic absorption; reduced duration of action
Factors influencing local anesthetic absorption and distribution:
1. presence of vasoconstrictors
2. injection site
3. dosage
4. A & C
5. A, B & C
Results of local vasoconstriction on local anesthetics
1. increased local anesthetic neuronal uptake
2. reduced local anesthetic blood levels -- reduced by as much as 1/3
3. both
4. neither
Inclusion of a vasoconstrictor in the local anesthetic solution is least likely to prolong the action of:
1. procaine (Novocain)
2. mepivacaine (Carbocaine)
3. lidocaine (Xylocaine)
4. bupivacaine (Marcaine)
Example local anesthetic with intrinsic sympathomimetic, vasoconstrictive properties
1. mepivacaine (Carbocaine)
2. cocaine
3. procaine (Novocain)
4. lidocaine (Xylocaine)
5. all the above
Addition to vasoconstrictors may prolong/enhance spinal anesthesia by:
1. activating alpha2 adrenergic receptors
2. increase local neuronal local anesthetic uptake
3. both
4. neither
Effect of clonidine (Catapres) addition to local anesthetic solutions:
1. enhanced local anesthetic effectiveness
2. reduced local anesthetic effectiveness
3. no clonidine (Catapres) influence on local anesthetic efficacy
Anatomical side where rapid local anesthetic absorption would be expected:
1. tendon
2. tracheal mucosa
3. both
4. neither
Based on comparative vascularity, maximum local anesthetic blood levels as a function of injection sites for regional anesthesia:
1. intercostal
2. brachial plexus
3. sciatic nerve
Type of local anesthetic with wider distribution:
1. Amide agents
2. Ester agents
3. no difference
Following IV infusion of lidocaine (Xylocaine): initial high uptake into this organ:
1. Heart
2. Brain
3. Lung
4. Kidney
5. Fat