Flashcards in Midterm Deck (74)
What are the 3 parts of local anesthetic?
1. Aromatic Group
2. Intermediate Chain
3. Secondary or Tertiary Amine
Confers lipophilic properties:
Supplies spatial separation between lipophilic and hydrophilic ends and connects them with an ester or amide linkage:
Affects pKa (& lips vs. water solubility) and influences speed of onset:
Secondary or tertiary amine
T/F: secondary/tertiary amines are bases:
How strongly the organic base portion of the L.A. molecule holds onto its proton (AKA acid dissociation constant):
High or low pKa:
weaker acid (stronger bases)
Hold proton more tightly
Remain positively charges and cross cell membranes poorly.
High or low pKa:
Shed proton more easily.
Become non-ionized "free bases".
Cross membranes more easily.
Which locals has a high pKa and slower onset?
1. Bupivacaine (Marcaine)
LAs stabilize cell membranes.
LAs act mainly be promoting rapid Na+ influx.
F: LAs act mainly by inhibiting rapid Na+ influx.
T/F: LAs are unusual in that they lose their effect when absorbed into the blood stream.
How does an LA stop working (numbness goes away)?
Duration of action is based on _____ ______ not metabolic transformation (half-life).
Half- life has a bearing on _____, not duration of action.
Local are all vasodilators except for ____.
Vasoconstrictors are needed to slow _____.
Which area for anesthesia takes the longest to develop and leaves first?
Which lasts longer, nerve blocks or infiltration?
Which amides are metabolized in the blood?
Only Articaine (septocaine).
All others are metabolized in the liver.
Where are esters metabolized?
Cocaine = liver
Procaine (Novocaine) and Benzocaine = blood
Which LAs are excreted only in the kidneys, not as metabolites?
Which LAs are excreted through the kidneys and as metabolites?
Which 2 LA's have a rapid onset?
Rate at which local is removed from the plasma:
List duration of action of locals, shortest to longest:
1. Mepivicaine (Carbocaine)
2. Lidocaine (Xylocaine)
3. Articaine (Septocaine)
4. Marcaine (Bupivicaine)
Which LA is not recommended in pedo or cognitively impaired adults?
Accumulation of orthotoludine in the blood can produce this:
Which two LAs can produce methemoglobin?
Prilocaine and Articaine (Septocaine)
T/F: Methemoglobin is methylated hemoglobin:
F: it is hemoglobin where the iron has been oxidized to the ferric (Fe3+) instead of ferrous (Fe2+) state.