Local Anesthetics Flashcards
Chloroprocaine (Nesacaine)
Chemical Classification
&
MOA
Ester
Short acting
Intracellular Voltage-Gated Na+ Channel Blocker; Blocks initiation & conduction of
nerve impulses
Chloroprocaine (Nesacaine)
Acid/Base
pKa
Lipid Solubility
Protein Binding
Acid/Base
Weak base
pKa
8.7
Lipid Solubility
Low
Protein Binding
Low
Chloroprocaine (Nesacaine)
Dosing
Max Infiltration Dose:
600 mg
6 mg/kg w/o EPI
14 mg/kg w/ EPI
Chloroprocaine (Nesacaine)
Onset
Duration
Onset
Rapid
Duration
30-45 min
Chloroprocaine (Nesacaine)
Metabolism
&
Elimination
Plasma:
Hydrolysis by plasma cholinesterase enzymes
Metabolite:
Para aminobenzoic acid (PABA)
Allergy Concern
Renal Excretion
Fastest metabolism rate by 3.5x
Chloroprocaine (Nesacaine)
Side Effects
&
Considerations
Prolonged effects d/t ↓ hydrolysis occur in hepatic disease & ↑BUN
↑ sensitivity d/t
↓ PChE levels;
↓protein levels
Procaine (Novocaine)
Chemical Classification
&
MOA
Ester
Short acting
Intracellular Voltage-Gated Na+ Channel Blocker; Blocks initiation & conduction of
nerve impulses
Procaine (Novocaine)
Acid/Base
pKa
Lipid Solubility
Protein Binding
Acid/Base
Weak Base
pKa
8.9
Lipid Solubility
0.6
Protein Binding
6%
Procaine (Novocaine)
Dosing
Max Infiltration Dose:
500 mg
7 mg/kg w/o EPI
8.5 mg/kg w/ EPI
Procaine (Novocaine)
Onset
Duration
Onset
Slow
Duration
45-60 min
Procaine (Novocaine)
Metabolism
&
Elimination
Plasma:
Hydrolysis by plasma cholinesterase enzymes
**Metabolite: **
Para aminobenzoic acid (PABA)
Allergy Concern
Renal Excretion
Metabolism Rate - Intermediate
Procaine (Novocaine)
Side Effects
&
Considerations
Prolonged effects d/t
↓ hydrolysis occurs in hepatic disease & ↑BUN
↑ sensitivity d/t
↓ PChE levels;
↓protein levels
Tetracaine (Dicaine)
Chemical Classification
&
MOA
Ester
Long acting
Intracellular Voltage-Gated Na+ Channel Blocker; Blocks initiation & conduction of
nerve impulses
Tetracaine (Dicaine)
Acid/Base
pKa
Lipid Solubility
Protein Binding
Acid/Base
Weak Base
pKa
8.5
Lipid Solubility
80
Protein Binding
76%
Tetracaine (Dicaine)
Dosing
Local Total Max Dose:
100 mg (topical)
3 mg/kg w/o EPI
3 mg/kg w/ EPI
Tetracaine (Dicaine)
Onset
Duration
Onset
Slow
Duration
60-180 min
Tetracaine (Dicaine)
Metabolism
&
Elimination
Plasma:
Hydrolysis by plasma cholinesterase enzymes
Metabolite:
Para aminobenzoic acid (PABA)
Allergy Concern
Renal Excretion
Metabolism Rate - Slowest
Tetracaine (Dicaine)
Side Effects
&
Considerations
No vasodilatory activity
Prolonged effects d/t
↓ hydrolysis occurs in hepatic disease & ↑BUN
↑ sensitivity d/t
↓ PChE levels;
↓protein levels
Liposome; used to upload ↑ amount of LA into molecule & have consistent release of
LA in
Other formulation:
Tetracaine Gel 4%
Lidocaine (Xylocaine)
Chemical Classification
&
MOA
Amide - Intermediate Acting
Intracellular Voltage-Gated Na+ Channel Blocker; Blocks initiation & conduction of
nerve impulses
Lidocaine (Xylocaine)
Acid/Base
pKa
Lipid Solubility
Protein Binding
Acid/Base
Weak Base
pKa
7.9
Lipid Solubility
2.9
Protein Binding
70%
pKa closest to physiologic pH = faster OOA
Lidocaine (Xylocaine)
Dosing
Max Infiltration Dose:
300 mg;
500 mg w/ EPI
5 mg/kg w/o EPI
7 mg/kg w/ EPI
Max Spinal Dose:
100 mg
Lidocaine (Xylocaine)
Onset
Duration
Onset
Rapid
Duration
60-120 min
Lidocaine (Xylocaine)
Metabolism
&
Elimination
Hepatic:
Oxidative dealkylation by microsomal enzymes
Metabolites:
Xylidide
Monoethylglycine-xylidide
Lungs:
1st Pass
Renal Excretion:
5%
Metabolism Rate - Intermediate
Lidocaine (Xylocaine)
Side Effects
&
Considerations
Vasodilatory activity = ↑potency & DOA
Metabolite monoethylglycine-xylidide accounts for 75% of antidysrhythmic effects
Highest risk for TNS when given intrathecally
Prolonged clearance in hepatic disease
Can cross
placental barrier
↑ sensitivity d/t
↓ PChE levels;
↓protein levels
Prolonged clearance w/ PIH
Liposome; used to upload ↑ amount of LA into molecule & have consistent release of
LA in tissues
Lidocaine (Xylocaine)
Other Indications
Eutectic Mixture of LA (EMLA)
Lidocaine 2.5% + Prilocaine 2.5% = 5% LA
Dose: 1-2 g/10 cm2 area
Readiness: 45 min OOA
Duration: 2 hrs
Prilocaine
Chemical Classification
&
MOA
Amide - Intermediate
Intracellular Voltage-Gated Na+ Channel Blocker; Blocks initiation & conduction of
nerve impulses
Prilocaine
Acid/Base
pKa
Lipid Solubility
Protein Binding
Acid/Base
Weak Base
pKa
7.9
Lipid Solubility
0.9
Protein Binding
55%
pKa closest to physiologic pH = faster OOA
Prilocaine
Dosing
Max Infiltration Dose:
400 mg
6 mg/kg w/o EPI
8.5 mg/kg w/ EPI
Prilocaine
Onset
Duration
Onset
Slow
Duration
60-120 min
Prilocaine
Metabolism
&
Elimination
Hepatic:
Microsomal enzymes
Metabolite:
Ortholuidine
Lungs:
1st Pass
Renal Excretion:
5%
Metabolism Rate - Most Rapid
Prilocaine
Side Effects
&
Considerations
Less vasodilatory activity
Methemoglobinemia @ dose >600 mg d/t ortholuidine metabolite oxidizing Hgb
Can cross placental barrier
↑ sensitivity d/t
↓ PChE levels;
↓protein levels
Tx for methemoglobin;
Methylene Blue:
IV: 1-2 mg/kg
over 5 min
Max: 7-8 mg/kg
OOA: 30-60 min
Prilocaine
Other Indications
Eutectic Mixture of LA (EMLA)
Lidocaine 2.5% + Prilocaine 2.5% = 5% LA
Dose: 1-2 g/10 cm2 area
Readiness: 45 min OOA
Duration: 2 hrs
Mepivacaine (Carbocaine)
Chemical Classification
&
MOA
Amide - Intermediate Acting
Intracellular Voltage-Gated Na+ Channel Blocker; Blocks initiation & conduction of
nerve impulses
Mepivacaine (Carbocaine)
Acid/Base
pKa
Lipid Solubility
Protein Binding
Acid/Base
Weak Base
pKa
7.6
Lipid Solubility
1
Protein Binding
77%
pKa closest to physiologic pH = faster OOA
Mepivacaine (Carbocaine)
Dosing
Max Infiltration Dose:
300 mg;
500 mg w/ EPI
5 mg/kg w/o EPI
7 mg/kg w/ EPI
Max Spinal Dose:
100 mg
Mepivacaine (Carbocaine)
Onset
Duration
Onset
Slow
Duration
90-180 min
Mepivacaine (Carbocaine)
Metabolism
&
Elimination
Hepatic:
Microsomal enzymes
Renal Excretion:
5%
Metabolism Rate - Intermediate
Mepivacaine (Carbocaine)
Side Effects
&
Considerations
Dysrhythmias; SB & SA
Subsequent dose (2nd)
↑ risk of dysrhythmias
↑ HR & SBP; ANS response
Lacks vasodilatory activity
Highest risk for TNS when given intrathecally
Can cross placental barrier
Prolonged eliminationin fetus
↑ sensitivity d/t
↓ PChE levels;
↓protein levels
Bupivacaine (Marcaine)
Chemical Classification
&
MOA
Amide - Long Acting
Intracellular Voltage-Gated Na+ Channel Blocker; Blocks initiation & conduction of
nerve impulses
Bupivacaine (Marcaine)
Acid/Base
pKa
Lipid Solubility
Protein Binding
Acid/Base
Weak Base
pKa
8.1
Lipid Solubility
28
Protein Binding
95% to α-1-acid glycoprotein
Bupivacaine (Marcaine)
Dosing
Max Infiltration Dose:
175 mg
225 mg w/ EPI
2.5 mg/kg w/o EPI
2.5 mg/kg w/ EPI
Max Spinal Dose:
20 mg
Bupivacaine (Marcaine)
Onset
Duration
Onset
Slow
Duration
240-480 min
Bupivacaine (Marcaine)
Metabolism
&
Elimination
Hepatic:
Aromatic hydroxylation, N-dealkylation, amide hydrolysis & conjugation by microsomal enzymes
Lungs:
1st Pass
Dose-dependent
Renal Excretion:
5%
Metabolism Rate - Slowest
Bupivacaine (Marcaine)
Side Effects
&
Considerations
Vasodilatory activity
↑ affinity for cardiac toxicity in neuraxial anesthesia
Least risk for TNS when given intrathecally
Continuous or intermittent epidural infusions can cause hepatic toxicity
Can cross placental barrier
↑ sensitivity d/t
↓ PChE levels;
↓protein levels
Liposome; used to upload ↑ amount of LA into molecule & have consistent release of
LA in tissues
FDA released Bupivacaine ER (Exparel); up to 90 hrs
Bupivacaine (Marcaine)
Other Indications
Combination of Chloroprocaine & Bupivacaine has rapid onset w/
8.4% NaHCO3 (1 ml ONLY) in 30 ml of LA
Ropivacaine (Naropin)
Chemical Classification
&
MOA
Amide - Long Acting
Intracellular Voltage-Gated Na+ Channel Blocker; Blocks initiation & conduction of
nerve impulses
Ropivacaine (Naropin)
Acid/Base
pKa
Lipid Solubility
Protein Binding
Acid/Base
Weak Base
pKa
8.1
Lipid Solubility
~2.9-28
Protein Binding
94% to α-1-acid glycoprotein
Ropivacaine (Naropin)
Dosing
Max Infiltration Dose:
200 mg
3 mg/kg w/o EPI
4 mg/kg w/ EPI
Ropivacaine (Naropin)
Onset
Duration
Onset
Slow
Duration
240-280 min
Ropivacaine (Naropin)
Metabolism
&
Elimination
Hepatic:
CYP450 enzymes
Renal Excretion:
5%
