LAs Flashcards
max dose: cocaine
3 mg /kg
anomalies with cocaine:
Heavily liver metabolized
Excreted unchanged by kidneys at higher percentage
Overall longer metabolism than most esters
Vasoconstriction! Unique among LAs
Causes SE of euphoria and increased SNS outflow
max dose: procaine
7 mg / kg
Special notes on procaine:
Increased incidence of CNS effects
increased PO-Nausea
Metabolites interfere with sulfa abx
max dose: Tetracaine
3 mg /kg
Special notes Tetracaine:
primarily used in spinal / corneal anesthesia
Very long DOA for ester r/t increased protein binding
Higher risk for TNS
max dose: chloroprocaine
12 mg/kg
onset of chloroprocaine:
pKa
onset: fast
pKa = 8.7
given at higher concentrations 2-3%
Notes on chloroprocaine:
great for OB anesthesia r/t minimal protein binding = rapid metabolism
Max dose: Mepivicane
max dose: 4mg/kg or with epi 7mg/kg
notes on Mepivicaine:
less vasodilatory than Lido but similar drug
more CNS effects than lido
Max dose: etidocaine
4 mg/kg
Max dose: lidocaine
4 mg/kg or with epi 7 mg/kg
Notes on lidocaine:
spinal use associated with CE
2 active metabolites !
Max dose: Prilocaine
600 mg
Notes on prilocaine:
toxic metabolite: ortho-tuolidine -> r/f metheglobinemia
Max dose: Bupivicaine
2.5 mg/kg
spinal dose: Bupivicaine
15 - 20 mg
Notes on bupivicaine:
low incidence of CNS effects
VERY CARDIOTOXIC
great at differential blocks
Long duration (95%) protein bound
Max Dose: Levobupivicaine
Max dose: 2mg/kg
Spinal dose: Levobupivicaine:
15 - 20 mg
Notes levobupivicaine
S enantiomer of bupivicane
less of a half life
less cardiotoxic
Max dose: Ropivicaine
3 mg/kg, 3.5 mg/kg* with epi
spinal dose: ROPIVICAINE
15 - 20 mg
Notes on ropivicaine
s enantiomer of bupivicane homolog.
less cardio toxic.
more vasoconstriction
2 active metabolites
*shortest half life of levo/bu/ro
mepivicaine has a longer DOA than lido because
it has less vasodilatory effects .
mepivicaine is structurally similar to
bupivicane
mepivicaine is clinically similar to
lidocaine
Spinal concentration, dose, volume, duration for lidocaine,
1.5% or 5%
30-100mg
1-2mL
30-90 min
spinal concentration, dose, volume, duration for mepivacaine
4%
40-80 mg
1-2 mL
30-90 min
spinal concentration, dose, volume, duration for tetracaine
0.25 - 1 %
5 - 20 mg
1 - 4 mL
90 - 200 min
spinal concentration, dose, volume, duration, for bupivacaine
0.5%
15-20 mg
3-4 mL
90-200 min
spinal concentration, dose, volume, duration, for ropivacaine
0.75%
15-20 mg
2-3 mL
90-200 min
spinal concentration, dose, volume, duration for levobupivacaine
0.75%
15-20 mg
2-3 mL
90-200 min
LAs: with active metabolites:
ropivicane (2)
lidocaine (2)
prilocaine (1)
higher concentration =
faster onset b/c more molecules
systemic effects are more likely with
amides
seizures in CNS toxicity are followed by
CNS depression
possibly hypotension, apnea
population at increased risk of CV collapse with bupivocaine
pregnancy
hypoxia
pH abnormalties
CV modulating drugs [propofol, volatile agents]
lipid for bupivacaine
intralipid 20% 1.5 mL/lg rapid bolus immediately. follow with infusion 0.25 ml/kg/min x 10 minutes
drugs implicated in CE
lidocaine 5%, tetracaine, chloroprocaine (preservative?)
factors that increase the risk of CNS toxicity
hypercarbia (increases CBF)
hyperkalemia (increases resting membrane potential)
metabolic acidosis (decreases convulsions threshold and favors ion trapping in the brain)
difficulty of CPR with OD
bupivacaine > levobupivacaine > ropivacaine > lidocaine
site of injection and blood flow:
IV > tracheal > intrapleural > intercostal > caudal > epidural > brachial plexus > femoral > sciatic > SubQ
