Test 1 SG: Chapters 1-5 Flashcards
what does specific receptor theory propose?
local anesthetics act by binding to specific receptors on the sodium channel
most favored theory of where local anesthetics work
specific receptor theory
local anesthetics are classified by their ability to react with specific receptor sites where?
sodium channel
mV of the nerve at resting potential
-70mV
mV of nerve at rapid depolarization
+40mV
At resting state the nerve membrane is slightly permeable to what?
sodium ions
repolarization is caused by the inactivation of increased permeability to what?
sodium ions
what is the magnitude of the decrease in negative transmembrane potential that is required to initiate an action potential?
firing threshold
According to your local anesthesia book, axolemma is another name for what?
nerve membrane
methods or substances that produce a ____ and ____ state are used in clinical practice to produce local anesthesia.
transient
completely reversible
example of a potent injectable local anesthetics that is relatively ineffective when applied topically to mucous membrane
procaine
mepivicaine
why is dyclonine not administered by injection?
because of its tissue irritating properties
the rate of conduction is (higher, lower) in unmyelinated nerve fibers compared to myelinated nerve fibers. why?
lower
because myelinated nerve conduct impulses at much faster rate than an unmyelinated nerve of equal size
the potency of a local anesthetic is controlled by the ___ of the molecule
lipid solubility
the duration of action of the local anesthetic is controlled by the ___ of the molecule
protein binding
what is a fasciculi?
nerve bundles of 500-1000 nerve fibers
what is the initial action of cocaine
vasodilation
what is a potent vasodilator that can be used when peripheral blood flow has been compromised due to accidental intraaterial injection of a drug?
procaine
T/F: most local anesthetic drugs are easily absorbed from the GI tract following oral administration
false
what is a major metabolic by product of an ester local anesthetic?
PABA
what condition is a person possibly suffering from if they have an inability to hydrolyze ester local anesthetics and other chemically related drugs? what kind of trait is this condition?
atypical form of pseudocholinesterase
hereditary
what is a chemically related drug to esters?
succinylcholine
what is a short-acting muscle relaxant employed frequently during the induction phase of general anesthesia
succinylcholine
what does the plasma pseudocholinesterase do the short-acting muscle relaxant employed frequently during the induction phase of general anesthesia?
hydrolyzes of succinylcholine blood levels fall and spontaneous respiration resumes
example of a relative contraindication to the administration of amide local anesthetic drugs?
liver dysfunction
a patient who has received large doses of prilocaine could possibly develop what?
methemoglobinemia
what is the primary excretory organ for both the local anesthetic and its metabolites
kidneys
what is the concern for patient with significant renal impairment?
maybe unable to eliminate parent local anesthetic compound or its major metabolites from the blood
what is the pharmacological action of local anesthetics on the CNS
depression
what LA are used to terminate or decrease the duration of both grand mal and petit mal seizures?
procaine
mepivicaine
lidocaine
what is the area called where the convulsive episode originates on the brain?
epileptic focus
what is the therapeutic doses of some local anesthetics for interrupting status epilepticus? give amount and rate.
2-3mg/kg given at rate of 40-50mg/min
primary effect of local anesthetics on BP is
hypotension
what is pharmacologic disorder in which genetic variant in individual alters that person’s response to certain drugs? what is another name for condition?
malignant hyperthermia
hyperpyrexia
cyanosis, tachycardia, tachypnea, unstable BP, respiratory and metabolic acidosis, fever (108F or more), muscle rigidity and death are clinical manifestations of what condition?
malignant hyperthermia
what is the chemical name of catechol?
orthodihydroxybenzene
vasoconstrictors resemble the response of what type nerve stimulation
adrenergic
reasons why vasoconstrictors are important additions to a local anesthetic solution
- constrict blood vessels
- slows absorption
- blood levels lowered to decrease toxicity
- keep local anesthetic in area longer
- controls bleeding at site
how are vasoconstrictors classified?
sympathomimetic or adrenergic drugs
list 5 catecholamines found in body
epinephrine norepinephrine levonordefedrin isoproterenol dopamine
what are the 4 adrenergic receptors?
alpha 1
alpha 2
beta 1
beta 2
which receptor is found in lungs
beta 2
which receptor is found in excitatory-postsynaptic
alpha 1
what are the disadvantages of sodium bisulfite?
more acidic
delayed onset of anesthesia
does levonordefrin produce more or less cardiac stimulation than epinephrine?
less
what local anesthetic is a concern for patients on acetaminophen?
prilocaine
bupivacaine is not recommended for what type of patients?
younger patients
physically and mentally disabled
T/F: Cocaine is highly soluble in water
true
what is the uncharged molecules in LA called?
free base form RN
what is the charged molecule called?
cations
why are local anesthetics acidified by manufacturers
to inhibit oxidation of vasopressor
pH of normal tissue
7.4
basic LA injected into acidic infected area
base + acid= salt
neural cytoplasm known as
axoplasm
pH of inflamed tissue
5-6
pH of solutions with vasoconstrictor
3.5
pH of solutions without vasoconstrictor
5.5-7
what does acidification of tissue do to local anesthetics
decrease effectiveness
what is concern of “off-centered perforation” of anesthetic carpules
leakage of anesthetic solution flow into patients mouth
what does it mean if blood is visible in a cartridge
needle tip rests within lumen of blood vessel
