Local Anesthetics Flashcards
Where do local anesthetics bind to the sodium channel?
the alpha subunit on the inside of the sodium channel when it’s in its active or inactive state
Do local anesthetics affect RMP or TP?
No, neither. They only prevent the nerve from repolarizing.
What characteristic is onset of action of a LA most related to?
pKa
What characteristic is potency of a LA most related to?
Lipid solubility
What is the max dose of levobupivacaine?
2 mg/kg
150 mg
What is the max dose of bupivacaine?
2.5 mg/kg
175 mg
What is the max dose of bupivacaine w/ epi?
3 mg/kg
200 mg
What is the max dose of ropivacaine?
3 mg/kg
200 mg
What is the max dose of lidocaine?
4.5 mg/kg
300 mg
What is the max dose of mepivacaine?
7 mg/kg
400 mg
What is the max dose of lidocaine w/ epi?
7 mg/kg
500 mg
What is the max dose of prilocaine?
8 mg/kg
<70 kg = 500 mg
>70 kg = 600 mg
What is the max dose of procaine?
7 mg/kg
350-600 mg
What is the max dose of chloroprocaine?
11 mg/kg
800 mg
What is the max dose of chloroprocaine w/ epi?
14 mg/kg
1,000 mg
What characteristic is duration of action of a LA most related to?
Protein binding
What SS appear when the plasma concentration of lidocaine is 1-5 mcg/mL?
analgesia
What SS appear when the plasma concentration of lidocaine is 5-10 mcg/mL?
numbness of lips and tongue
tinnitus
restlessness
vertigo
skeletal muscle twitching
blurred vision
hypotension
myocardial depression
What SS appear when the plasma concentration of lidocaine is 10-15 mcg/mL?
seizures
loss of consciousness
What SS appear when the plasma concentration of lidocaine is 15-25 mcg/mL?
coma
respiratory arrest
What SS appear when the plasma concentration of lidocaine is >25 mcg/mL?
cardiovascular collapse
What is the dose of lipid emulsion therapy in LAST in a patient > 70kg?
bolus: 100 mL over 2-3 min
infusion: 250 mL over 15-20 min
if needed, repeat bolus and/or double infusion
What is the dose of lipid emulsion therapy in LAST in a patient < 70kg?
bolus: 1.5 mg/kg LBW over 2-3 min
infusion: 0.25 mL/kg/min
if needed, repeat bolus or double infusion rate
What is the proposed mechanism of action of lipid emulsion therapy in LAST?
Lipid sink: intravascular reservoir for LA and reduces Cp of LA
Membrane effect: impairs LA binding to voltage-gated sodium channels
Metabolic effect: enhanced myocardial fatty acid metabolism
Inotropic effect: increased Ca influx and intracellular Ca concentration