Pharmacology and Pain Control Flashcards

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

Answer: Articaine

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

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

Answer: 7.0 mg/kg

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

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

Answer: Prilocaine

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

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

Answer: High protein binding

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

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

Answer: Decreased tissue pH increases the ionized cationic fraction

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

Which local anesthetic, used as a plain 3% solution, gives adequate pulpal anesthesia without a vasoconstrictor because it causes little vasodilation?

Answer: Mepivacaine 3%

Mepivacaine causes only mild vasodilation, so the 3% plain solution still gives a short period of pulpal anesthesia.

For a patient with significant cardiovascular disease, what is the commonly cited maximum epinephrine dose per dental appointment?

Answer: 0.04 mg

The cardiac dose limit of 0.04 mg is about two cartridges of 1:100,000 epinephrine.