mechanism of LA action
block peripheral nerve conduction by decreasing the sodium ion permeability of the nerve membrane. Inhibit the influx of sodium ions by blocking sodium channels in the neuron membrane
which fibers are affected first
small unmyelinated fibers are affected first then large myelinated fibers are affected last
what kind of base is local anesthetic
they are weak bases that work poorly in inflamed tissues
what is the best way to reduce the risk of systemic toxicity
aspiration
what are the two major families of local anesthetics
amides and esters
where are amides metabolized
liver
what is the endings for amides
i-caines
drug examples for amides
lidocaine, mepivacaine, prilocaine, bupivicaine, articaine
where are esters metabolized at
in the blood plasma
How are esters administered
topical only
drug examples for esters
benzocaine and novocaine
the shortest duration local anesthetic
mepivacaine aka carbocaine
what is the longest duration local anesthetic
bupivicaine aka marcaine
what local anesthetic should be avoided in patients with anemia and patients taking acetaminophen
prilocaine aka citanest
what local anesthetic inceases the risk of paresthesia especially mandibular block
articaine aka septocaine
the purpose of vasconstrictors in local anesthetic
prolong and increase the depth of anesthesia, delay absorption, decreasing toxicity, decrease bleeding
what are the names of the two vasconstrictors used
epinerphrine and levonordefrin
is epinephrine contraindicated in patient with controlled hypertension
no