Flashcards in Local Anesthetics Deck (63)
What was the first local anesthetic and when was it introduced?
What is unique to cocaine as a LA?
It causes profound vasoconstriction
(others will cause vasodilation)
Is cocaine still in use today? If yes, what is it typically used for?
Yes! It is a schedule II drug typically used for nasal surgery in humans (or other highly vascular surgeries)
What are the two classifications of LAs?
What is the general structure of LAs?
Aromatic ring and hydrophilic portion joined by a hydrocarbon chain
They are classified by the hydrocarbon chain
What are the esters?
Cocaine, procaine, chloroprocaine, tetracaine
What are the amides?
Lidocaine, mepivicaine, bupivicaine, etodicaine, prilocaine, ropivacaine
What is the general MOA of LAs?
Bind to sodium channels in nerve membranes slowing rate of depolarization
Threshold potential cannot be reached and action potentials are not propagated
T/F: LAs are weak acids.
False- all LAs are weak bases
What kind of tissues will increase ionization of LAs?
Acidic tissues (ie infection esp) which makes them inactive
What three things affect potency, onset, and duration?
- protein binding
- lipid solubility
Will a higher or lower pK increase onset time?
Lower- closer to tissue pH
Will a greater or lesser affinity to protein binding increase duration of action?
High protein binding affinity
Will a higher or lower lipid solubility increase potency?
Higher the lipid solubility, higher the potency
What is the only LA that can be given IV or for IVRA?
What is lidocaine onset/duration?
Fast onset, short duration
Is lidocaine absorbed transcutaneously?
What are the systemic/IV effects of lidocaine?
2. Decrease MAC
4. Free radical scavenger
5. Improves GI motility
What is the onset/duration of bupivicaine?
Immediate onset, moderate duration (3-8hr)
T/F: Bupivicaine has the lowest cardiovascular toxicity.
FALSE- highest toxicity, do not give IV
What is mepivacaine used for?
Nerve blocks, intra-articular analgesia (large animals)
What is the onset/duration of mepivacaine?
Fast onset, short duration (1.5-3)
What is the onset/duration of ropicacaine?
Intermediate onset, moderate duration (3-8hr)
T/F: Ropivacaine is less cardiotoxic than bupivacaine.
What is procaine commonly used for?
Procaine penicillin G suspensions (PPG)
What are tetracaine and proparacaine commonly used for?
What is benzocaine commonly used for?
Historically used as a laryngeal spray for intubation
What does systemic absorption depend on?
1. Site of injection
3. Drug Characteristics
4. If epinephrine is used
What site of injection has the fastest absorption?