Anesthesia Pharmacology: Local Anesthetics Practice
Questions
Local anesthetic pulmonary extraction:
- from the arterial circulation
- from the venous circulation
Propranolol (Inderal) effects on local anesthetic pulmonary extraction and clearance:
- inhibits bupivacaine (Marcaine) extraction
- reduces lidocaine (Xylocaine) plasma clearance
- increases bupivacaine (Marcaine) plasma clearance
- A & B
- A, B & C
Local anesthetic type (ester or amide) more likely available for placental transfer:
- Ester-type
- Amide-type
Effect of fetal acidosis on local anesthetic accumulation in the fetus
- enhanced accumulation
- reduced accumulation
- no effect on local anesthetic accumulation
Clearance: amide local anesthetic
- rapid hydrolysis
- hepatic mediation
- significant renal excretion
Amide-type local anesthetics:
- lidocaine (Xylocaine)
- ropivacaine (Naropin)
- dibucaine (Nupercainal, generic)
- mepivacaine (Carbocaine)
- all the above
Slows metabolism among the amide-type local anesthetics
- prilocaine (Citanest)
- ropivacaine (Naropin)
- lidocaine (Xylocaine)
- mepivacaine (Carbocaine)
Mechanism(s) for Ester-type local anesthetic metabolism:
- hydrolysis by plasma cholinesterase
- hydrolysis by hepatic cholinesterase
- both
- neither
Local anesthetic most rapidly metabolized by cholinesterase
- tetracaine (pontocaine)
- procaine (Novocain)
- chloroprocaine (Nesacaine)
Systemic toxicity of ester-type local anesthetics:
- directly proportional to hydrolytic rate
- inversely proportional to hydrolytic rate
- independent of hydrolytic rate
Factors that influence ester-type local anesthetic duration of action:
- hepatic disease
- injection site
- elevated BUN
- A & C
- A, B & C
Effects on ester-type local anesthetic duration of action in patients with atypical plasma cholinesterase:
- reduced duration
- increased duration
- no effect on duration of action
Example(s) of ester-type local anesthetics:
- procaine (Novocain)
- tetracaine (pontocaine)
- cocaine
- A & C
- A, B & C
Factors which influence lidocaine (Xylocaine) metabolism:
- hepatic disease
- volatile anesthetics
- reduced hepatic blood flow
- A & C
- A, B & C
Local anesthetic which may cause cyanosis secondary to reduced oxygen transport
- lidocaine (Xylocaine)
- bupivacaine (Marcaine)
- mepivacaine (Carbocaine)
- prilocaine (Citanest)
- procaine (Novocain)
Most slowly eliminated among amide derivative local anesthetics:
- mepivacaine (Carbocaine)
- bupivacaine (Marcaine)
- dibucaine (Nupercainal, generic)
- procaine (Novocain)
Rationale for adding epinephrine to local anesthetic solutions:
- reduced systemic absorption
- prolongation of conduction blockade
- higher anesthetic concentration near nerve fibers
- all of the above
Factors influencing effectiveness of epinephrine or local anesthesia:
- choice of local anesthesia
- level of sensory blockade required or spinal anesthesia
- both
- neither
Inclusion of epinephrine in local anesthetic solutions decreases time to onset:
- true
- false
Toxicities associate with systemic epinephrine absorption following use of local anesthetic solutions containing epinephrine
- arrhythmias
- hypotensive responses
- both
- neither