Question | Answer |
2 afferent fibers that carry nocioceptor information | Aδ-fibers and C-fiber |
Pain from Heat about 45*C is carried by what type of fiber | C-fiber |
Pain from cold below 5*C is carried by what type of fiber? | Aδ-fibers |
High threshold mechanical nocioceptors transmit pain via what type of fiber? | Aδ-fibers and some Aβ-fibers |
Polymodal chemical, temperature, and mechanical nocioceptor transmits pain via what fibers? | C-fibers |
LA’s affect nerves in which order? | small non-myelinated>small myelinated>large non-myelinated>large myelinated |
Which type of feeling dulls first from LA’s? 2nd? 3rd? 4th? | pain>temp>touch>pressure |
Do you need more or less anesthetic in infected tissue? | more; infected=acidic, LA’s are alkali and become neutralized and unable to bind |
Speed and fiber of 1st pain? | 5-25 m/s and Aδ-fibers |
Speed and fiber of 2nd pain? | 1 m/s and C-fibers |
Mnemonic for amide-linked LA’s | amIdes have 2 I’s in the name; Lidocaine, Prilocaine, Bupivicaine, Articaine |
Site of action for LA’s? and conformation affinity? | cytoplasmic side of Na+ channel, prefers intermediate, open, and inactive conformations |
Higher or lower hydrophobicity increases LA’s partition through membranes? | Higher (but not too high or they are stuck in the membrane) |
High, moderate, or low hydrophobicity is wanted in a good LA? | moderate |
What functional group confers the hydrophobicity of an LA? | aromatic group |
Protonated amine group + , = or – charge? | + |
Deprotonated amine group: +, =, or – charge? | = |
Protonated or deprotonated forms of amine cross membranes? | deprotonated |
Protonated or deprotonated forms of amine binds to target site? | protonated |
Most difficult nerve bundle layer for LA’s to penetrate? | perineurium |
Where are ester-linked LA’s metabolized? By what? | tissue and plasma; esterases |
Where are amide-linked LA’s metabolized? By what? | liver; P450 enzymes |
Topical anesthetic mixture with concern of “toxicity or addiction” | TAC: tetracaine/Adrenaline/Cocaine |
Used instead of TAC | EMLA |
Local anesthetics cause a dose-dependent effect on the heart. What is it? | inotropic effect |
LA that is also Class I antiarrhythmic | lidocaine |
Allergic reactions to LA’s usually happen with this class | ester-linked |
Ester-linked LA that has a know allergenic metabolite. What is the LA? What is the metabolite? | Procaine; PABA |
4 ester-linked LA’s | procaine, 2-chloroprocaine, tetracaine, cocaine |
Don’t use this LA if being treated for acute bacterial Infx and Tx with sulfonamides | procaine |
Short-acting LA, with slow onset, metabolized in the blood stream and excreted by the kidneys | procaine |
Long acting, high potency, slowly degradation in blood stream. Usually used topically and spinally | tetracaine |
Most cardiotoxic LA | cocaine |
Used primarily in ophthalmic and topical anesthesia | cocaine |
Rapid onset, medium duration, mildly potent, little vasoconstrictive activity, eliminated in the liver | lidocaine |
For rapid onset of anesthesia do you want an LA with a low or high pKa? | low; further below 7.8 the more deprotonated molecules there will be and the faster they diffuse through membranes |
Used when a Pt needs medium/long local anesthesia but has a Hx of arrhythmias, and can’t handle Epi; hepatically metabolized | prilocaine |
Less cardiotoxic enantiomer of bupivacaine and 2 names | S-enantiomer; levobupivicaine/ropivicaine |
Long duration, highly potent, hepatically metabolized LA; has cardiotoxic SA | bupivacaine |
Used mainly in dentistry, partially metabolized peripherally and hepatically | articaine |
Mixture of these 2 LA’s used topically is named this | lidocaine and prilocaine; EMLA |
Used especially in OB epidurals | 2-chloroprocaine |