Local Pharmacodynamic Flashcards
LA differential blocking of nerve type most sensitive to least
Degree of myelination
Autonomic (c fiber)>Sensory (alpha d) Motor Fibers (alpha b)
Unique Property of Chloroprocaine, favorable population
Most Rapid Hydrosis of ester classes
Neurotoxicity due to bisulfite preservative
OB can be used due to rapid onset, decreased risk of systemic tox/fetal exposure
Useful in Liver dz and SZ
Transient Neurologic Symptoms
which drug, when sx, tx
Lidocaine in Spinals
Pain in Lower back, buttock, thighs
No motor sx
within 2 to 24hr onset and clears within 10 days
supportive pain meds with NSAIDs and opioid prn
Bupicivaine Unique characteristics
High quality sensory vs motor blockade
Severe refractory cardiovascular collapse with toxic intravascular doses
Liposomal Bupivicaine indication, unique characterstic, Max dose, caution
Used for single dose infiltration block for postsurgical anesthesia
Suspension promotes extended release 72 hr
with dilution can be maxed to 266 mg.
Should not be given directly after given other LA or other vasodilators due to systemic toxicity
LAT CNS
CNS (first):
1) Lightheadedness-
2) CN involvementperioral Numbness, Metallic Taste, Facial TIngling, Tinnitus, Slurred Speech,
Major CNS SZ, Unconsciousness, Hypercarbia/Resp arrest; Cardiovasc arrest
Determination of Potency of LA
Lipid Solubility:
Large alkyl Group;
Adding NaHCO3/Inc pH (more unionized form)t
LA MOA
Membrane stabilizdiing drug; affects sodium specific ion channels binds directly to cytoplasmic side
-ergo cannot conduction action potential
LA Structure and function
Weak base and passes through lipid cell membrane which then binds to sodium channel
Nerve Characteristics to LA sensitivity
Decreases with Thickness of myelin Sheath and Axonal Diameter
Least sensitive to most sensitive nerve fiber type
A-Alpha; Beta; Gamma; Delta
C
B
Action form of LA vs crossing form of LA
Crossing: Nonionized
Active: Ionized.
What determine onset of action of LA
pkA of Drug (lower better)
pH of area of effect (higher better; e.g hco3)
Lipid solubility
Lower distance of diffusion
What determine duration of LA [6]
Protein Binding (more the better)
Vascularization of Site (less is better)
Degee of Vasodilation (note all but crack are dilators)
Lipid solubility (higher the better)
Pseudocholinesteras deficiency (esp in liver dz) Addition of EPI or decadron
Metabolism and Class of LA
Esters: Procaine; Benzocaine (no i before caine)
Via Pseudocholinesterase into Para aminobenzoic acid (PABA)
Amide: Lidocaine; mepivicaine; ropivicaine; bupivicaine (i before caine)
VIa direct Liver metabolism
