Locals Flashcards
which of the following properties of epidurally administered local anesthetics determines the extent to which epinephrine will prolong the duration of blockade?
A. molecular weight
B. Lipid Solubility
C. pKa
D. Concentration
B. Lipid Solubility
The action of epidural narcotics is antagonized by the prior or concomitant administration of which of the following epidurally administered local anesthetics?
A. Lidocaine
B. Bupivacaine
C. Ropivacaine
D. Chloroprocaine
D. Chloroprocaine
Refractory cardiac arrest is MOST likely after the rapid unintentional IV injection of which of the following local anesthetics?
A. Lidocaine
B. Bupivacaine
C. Ropivacaine
D. Chloroprocaine
B. Bupivacaine
Transient neurologic syndrome (TNS) is MOST commonly seen after the spinal anesthetic injection of which local anesthetic?
A. Lidocaine
B. Bupivacaine
C. Prilocaine
D. Tetracaine
A. Lidocaine
Which local anesthetic has the MOST rapid metabolism in the maternal and fetal blood?
A. Lidocaine
B. Bupivacaine
C. Ropivacaine
D. Chloroprocaine
D. Chloroprocaine
Produces reversible conduction blockade of impulses along the _____ and _____ nerve pathways
central and peripheral nerve pathways
1st local anesthetic
Cocaine 1884
1st synthetic local (ester)
Procaine 1905
1st amide local
Lidocaine 1943
lipophilic and hydrophilic portions separated by _____
hydrocarbon
The lipophilic portion is the
Benzene ring (necessary for activity)
Ester
- CO-
Amide
- NHC-
Quaternary amine
Hydrophilic
What’s the benefit of S enantiomers?
less neuro and cardio-toxic
Mechanism of action:
Inhibit Na+ ions through the selective Na+ channels
-slows rate of depolarization
Threshold potential not reached= no action potential propogated
DOES NOT ALTER:
-resting membrane potential
-Threshold potential
Alpha subunit:
allows ion conduction and binds LA
LAs bind to Na+ channels only in the ____ and ___ states
Active and inactivated
Nerves with more activity =
faster blockade
Other sites of action
Voltage-dependent potassium channels
Calcium ion currents (L-type)
G protein-coupled receptors
Cm=
Minimum concentration to produce conduction blockade
Factors that increase Cm:
Larger diameter
Factors that decrease Cm:
Higher frequency
Higher pH
Inhibit Na+ ions passage through ion-selective Na+ channels
-Slows rate of depolarization
-Threshold potential not reached
-No action potential propagated
Locals don’t alter the ____ and ____ of the membrane potential
Resting membrane potential
Threshold potential
Locals don’t alter the ____ and ____ of the membrane potential
Resting membrane potential
Threshold potential
