Local Anesthetics Flashcards
Why do we use local anesthetics?
Analgesia
Decrease requirement for other drugs/inhalants/opioids
What are the advantages of local anesthetics?
Readily available
Effective
Affordable
Relatively safe
Easy to perform
What are the disadvantages of local anesthetics?
Dont always work
Can be time consuming
Toxicity/overdose
Motor block may complicate pt care
May not last long enough
Vasodilation
Possible CV effects w/ IV injection
What is the mechanism of action for local anesthetics?
Inhibit transmission of nerve impulses by blocking Na channels
What effect does inflammation have an lidocaine?
Decrease efficacy
Inflamed tissue has lower pH (more H+) which prevents lidocaine from dissociating
How does epinephrine affect lidocaine?
Addition of epi will prolong duration of action
What type of nerve fiber is likely to be affected first with local anesthetic?
Small, unmyelinated fibers: C fibers etc
How do local anesthetics exert an analgesic effect
Primarily block depolarization of A -delta and C fibers
How are amide local anesthetics metabolized?
liver
Is bupivacaine or lidocaine a more toxic drug?
Bupivicaine
What are the CS of lidocaine toxicity?
CNS: seizures, depression, coma, unconsciousness, resp arrest
CV: hypotension, decr CO, arrhythmias, CV collapse
How do you treat lidocaine tox?
Symptomatic
Iv fluids, intubation, O2, diazepam for seizures, monitor
How does systemic admin of lidocaine produce analgesia?
Inhibition of Na/K channels, NMDA receptors + glycine reuptake
What is nocita?
Slow release bupivicaine
What are advantages of Nocita?
3 days of analgesia
avoid need for post op opioids
