Term
| What is the molecular mechanism of action of Local anesthetics |
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Definition
Block Na Conduction into cell
Do not block K conduction |
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Term
| What nerves are typically affected first by local anesthetics |
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Definition
| B and C fibers (small unmyelinated: Autonomic/Sensory) |
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Term
| What factors determine Onset Time, Potency, and Duration of Action |
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Definition
Onset: Lower Pka or higher blood pH is faster
Potency: More lipid soluble is stronger
Duration: Higher affinity blocks wash out(longer) |
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Term
| How are the local anesthetics metabolized |
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Definition
Esters: Plasma Pseudocholinesterase produced by liver
Amides: Liver p450's |
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Term
| What is the prodrome to local anesthesia toxicity? |
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Definition
Lightheaded
Disturbances of Visual/Auditory
Dizziness
Disorientation
Drowsiness |
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Term
| What are the adverse effects of Local anesthetics and which anesthetics are particularly toxic? |
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Definition
CNS: Excitation followed by depression
Twitching, Convulsions-> CV/Respiratory depression, Coma
Cardiac: (-)Inotrope, Dysrythmias
Bipivacaine is most Cardiotoxic
Vessels: Vasoconstriction(Low dose), Vasodialation(High dose)
Methemoglobinemia: Benzocaine, Prilocaine
Muscle Necrosis
Allergies: Esters
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Term
| What is used to reverse cardiotoxicity of bipivacaine and how do you reverse methimoglobulinemia |
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Definition
Cardio: Intralipid infusion
Methimo: Methylene Blue reduces to ferrous state |
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Term
| What are drawbacks and advantages of Cocaine use as a local anesthetic |
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Definition
Dis: Local Nerve Toxicity
Adv:Vasoconstriction by blocking catecholamine reuptake |
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Term
| What are the kinetics of tetracaine and how is it used |
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Definition
Slow onset, Long Duration
Topical Anesthetic |
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Term
| Which ester anesthetic has the least toxicity, what toxicity is particular to this drug? |
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Definition
2-chloroprocaine
Never give IV->Thrombophlebitis |
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Term
| What are some drawbacks to benzocaine use and when is it typically used |
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Definition
Requires high concentration
Causes Methimoglobulinemia
Used in Mucous membrane procedures(Trachea) |
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Term
| what are the advantages/disadvantages of Dibucaine and when is it used |
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Definition
Adv: High Potency
Dis: High Toxicity and blocks Plasma Cholinesterase
Used Topically usually for hemorroids |
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Term
| When is Mepivacaine used and what are the drawbacks to its use |
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Definition
Epidural, Spinal, and Peripheral Nerve block
Potential for accumulation |
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Term
| What is Bupivacaine used for and what are the drawbacks |
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Definition
Spinal anesthesis
Lower doses used in Obstetrics to prevent motor block
Hyperbaric solutions prevent Cardiac block
Dis:Cardiac toxicity |
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Term
| What are the advantages and disadvantages of Ropivacaine |
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Definition
Adv: Less Cardiotoxic bc pure S isomer, better frequency dependent Block
Dis: Less potent, shorter duration
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Term
| What is typically the only anesthetic that epinephrine is used with |
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Definition
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Term
| What is the most rapidly metabolized Amide and what are its adverse effects |
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Definition
Prilocaine
Methimoglobulinemia |
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Term
| What are the local anesthetics used in Topical, ENT, Mucosal, Spinal(Labor) procedures |
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Definition
Topical: Tetracaine, Dibucaine(Cream-Hemorrhoids)
ENT: Cocaine
Mucosal: Benzocaine
Spinal: Bipivucaine |
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Term
| Why do esters cause allergies |
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Definition
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