DMD Pharmacology and Pain Control 2

Question 1

Which amide local anesthetic contains a thiophene ring and an ester side chain that allows partial hydrolysis by plasma esterases?

Accepted Answer

Articaine

Answer

Articaine is classified as an amide but its ester group lets plasma esterases inactivate it rapidly, giving a short half-life.

Question 2

Per the US product labeling, what is the maximum recommended dose of 4% articaine with 1:100,000 epinephrine for an adult?

Accepted Answer

7.0 mg/kg

Answer

US labeling lists 7 mg/kg as the maximum dose of articaine for adults.

Question 3

A patient develops cyanosis and chocolate-colored blood after receiving a large dose of local anesthetic. Which agent is most likely responsible?

Accepted Answer

Prilocaine

Answer

Prilocaine is metabolized to o-toluidine, which oxidizes hemoglobin to methemoglobin.

Question 4

Which property of bupivacaine is most responsible for its long duration of pulpal and soft-tissue anesthesia?

Accepted Answer

High protein binding

Answer

High protein binding keeps bupivacaine attached to sodium-channel proteins longer, which extends its duration of action.

Question 5

Why is local anesthesia often less effective when injected into acutely inflamed or infected tissue?

Accepted Answer

Decreased tissue pH increases the ionized cationic fraction

Answer

Acidic inflamed tissue shifts the drug toward its charged form, so less uncharged base can cross the nerve membrane.

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