Local Anesthetics Flashcards
Local anesthetics produce ___ (reversible/irreversible) conduction blockade of impulses along the ___ and ___ nerve pathways
Local anesthetics produce reversible conduction blockade of impulses along the central and peripheral nerve pathways
What was the first local anesthetic?
Cocaine–1884
What was the first synthetic ester local?
Procaine–1905
What was the first amide local?
Lidocaine–1943
Chemical structure of local anesthetics–___philic and ___philic portion separated by ___
Chemical structure of local anesthetics–lipophilic and hydrophilic portion separated by hydrocarbon
Lipophilic portion of LA is the ___ ring
Lipophilic portion of LA is the benzene ring–necessary for activity!
What part of LA structure is necessary for its activity?
Lipophilic benzene ring
___ (ester/amide) intermediate chain = -CO
Ester local intermediate chain = -CO
___ (ester/amide) intermediate chain = -NHC-
Amide local intermediate chain = -NHC-
Core structure for local anesthetics = a ___ ring and a ___ amine separated by an intermediate ___ group
Core structure for local anesthetics = a benzene ring and a quaternary amine separated by an intermediate carbon group
The bond between the benzene ring and the carbon group determines whether the drug is an amide or an ester–T/F?
True
There are ___ (few/many) lipid layers for local anesthetics to cross
There are many lipid layers for local anesthetics to cross
What are (2) types of enantiomers?
S and R enantiomers
Racemic mixtures contain ___ (one/both) type(s) of enantiomers
Racemic mixtures contain BOTH (S and R) types of enantiomers
Pure isomers contain ___ (one/both) type(s) of enantiomers
Pure isomers contain ONE type of enantiomer
What are the only (2) pure isomer local anesthetics? What enantiomer type are they?
-Ropivacaine
-Levobupivicaine
Both are pure isomers, S enantiomers
Each enantiomer binds to different receptors or enzymes, which changes pharmacokinetics, pharmacodynamics, and toxicity–T/F?
True
Which enantiomer is more beneficial? (R or S?) Why?
S enantiomers are more beneficial because they are less neuro- and cardiotoxic
How do local anesthetics work?–inhibit ___ ions passage through ion-selective ___ channels; this ___ (slows/speeds up) the rate of depolarization; threshold potential ___ (is/is not) reached; action potential ___ (is/is not) propagated
LAs inhibit sodium ions passage through ion-selective sodium channels; this slows the rate of depolarization; threshold potential is NOT reached; action potential is NOT propagated
LAs alter resting membrane potential and threshold potential–T/F?
FALSE–LAs do NOT alter resting membrane potential or threshold potential
What are (2) sodium channel subunits? Which subunit allows ion conduction and binds local?
- Alpha
- Beta
Alpha subunit allows ion conduction and binds local
Local anesthetic binds to receptors in ___ (activated/inactivated/both) state(s)
Local anesthetic binds to receptors in BOTH activated/inactivated states
When local anesthetics bind to receptors, the cells become ___ (permeable/impermeable) to sodium
When local anesthetics bind to receptors, the cells become IMPERMEABLE to sodium
Threshold potential not reached, action potential not propagated as a result
LA binding on ___ (internal/external) part of channel is thought to be most important
LA binding on INTERNAL part of channel is thought to be most important