Local Anesthetics Flashcards
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Main function of local anesthetics
Temporary interruption of all sensations over a specific area of the anatomy without loss of consciousness
Component of local anesthetics that enables penetration of nerve fibers.
Lipophilic component; attracted to clear lipids such as the phospholipid bilayer covering of nerves
Component of local anesthetics that allow for the diffusion of the drug through interstitial tissues
Hydrophilic component
Prototype of ester type of LA
Procaine
Prototype of amide type of LA
Lidocaine
Enzyme responsible for metabolism of ester type of LA and where is it found
Plasma pseudocholinesterase; in plasma
Enzyme responsible for metabolism of amide type of LA and where is it found
Hepatic microsomal enzyme system; liver
Anesthetic drug that produces the greatest vasodilation
Procaine
Highly toxic LA that cannot be used alone.
Propoxycaine
LA that is/are metabolized in both plasma and liver
Propoxycaine and articaine
Concentration of combined procaine + propoxycaine and its maximum recommended dose
2% procaine + 0.4% propoxycaine; 6.6mg/kg
Vasoconstrictors added to combined procaine + propoxycaine
1:20,000 norepinephrine
1:30,000 levonordefrin
Amide type of LA (6)
(LiMePriEtiArB)
Lidocaine
Mepivacaine
Prilocaine
Etidocaine
Articaine
Bupivacaine
Gold standard LA
Lidocaine
Maximum recommended dose for lidocaine
7.00mg/kg
absolute maximum dose for lidocaine
500mg
Vasoconstrictor usually added to lidocaine
1:50,000 epinephrine
1:100,000 epinephrine (ideal)
potency and toxicity of prilocaine
twice as potent with the same toxicity
Concentration of prilocaine
4% with 1:200,000 epinephrine or 4% plain
Maximum recommended dose for prilocaine
8.0mg/kg
absolute maximum dose for prilocaine
600mg
Contraindication of prilocaine
patients that may have decrease oxygen carrying capacity in the blood
Condition described as the increase of methemoglobin in the blood and which LA does this.
Methemoglobinemia; Prilocaine
Potency and toxicity of Mepivacaine
Twice as potent, 1.5-2.0x toxicity
LA with the slightest vasodilation
Mepivacaine
Concentration of mepivacaine
2% with 1:100,000 epinephrine or 3% plain
Maximum recommended dose for mepivacaine
6.6mg/kg
Absolute maximum dose for mepivacaine
400mg
Potency and toxicity of articaine
1.5x more potent, twice as toxic
Concentration of Articaine
4% with 1:100,000 or 1:200,000 epinephrine
Maximum recommended dose for articaine
7.0mg/kg
LA with a myocardial depressant property
articaine
Potency and toxicity of bupivacaine
4x more potent, <4x more toxic
Greatest vasodilating property among amide types of LA
bupivacaine
Concentration of bupivacaine
0.5% with 1:200,000 epinephrine
Contraindication for bupivacaine
Children younger than 12
MRD of bupivacaine
90mg (USA), 2.0mg/kg or 200mg (Canada)
LA withdrawn from the market
Etidocaine
Mrd of etidocaine
8.0mg/kg
Topical anesthetics (4)
Benzocaine
EMLA
Lidocaine
4% tetracaine HCl
Concentration of etidocaine
1.5% with 1:200,000
Content of EMLA
Lidocaine 2.5% + Prilocaine 2.5%
EMLA duration
20 mins
Formulations of topical lidocaine
Lidocaine base 5% (poor water solubility)
Lidocaine Hydrochloride 2% (water soluble)
Contraindication of 4% Tetracaine HCl
lacerated mucosal tissue
What is pKa
Dissociation constant
pH level where compound is half ionized, half un-ionized
Free base : (lipophilic/hydrophilic); Charged cation : (lipophilic/hydrophilic)
lipophilic; hydrophilic
High pH = shifts equilibrium to the (left/right)
right
Low pH = shifts equilibrium to the (left/right)
left
Low pKa = shifts equilibrium to the (left/right)
right
High pKa = shifts equilibrium to the (left/right)
left
First anesthetic approved for epinephrine sensitive patients
Mepivacaine
Incorporated to amides as an antioxidant and as a preservative
Sodium bisulfite
True allergy to anesthetic drug will manifest on the ____ exposure
Second
Added to anesthesia to make it closer to normal pH of tissue (isotope)
Sodium chloride
