Pharmacology and Therapeutics Flashcards

A patient on warfarin requires dental extractions. Which analgesic is SAFEST to prescribe postoperatively?

Answer: Acetaminophen 500 mg

Acetaminophen does not inhibit platelet function or significantly affect INR, making it the safest analgesic for patients on warfarin.

Which local anesthetic has the LONGEST duration of action for dental nerve blocks?

Answer: Bupivacaine 0.5%

Bupivacaine has the longest duration of action among dental local anesthetics, providing 4–12 hours of pulpal anesthesia with a vasoconstrictor.

Methemoglobinemia is a known adverse effect of which local anesthetic at high doses?

Answer: Prilocaine

Prilocaine is metabolized to o-toluidine, which oxidizes hemoglobin to methemoglobin, causing methemoglobinemia at high doses.

A patient taking a monoamine oxidase inhibitor (MAOI) requires local anesthesia. Which vasoconstrictor is CONTRAINDICATED?

Answer: Levonordefrin

Levonordefrin (neo-cobefrin) is a sympathomimetic whose pressor effects are dangerously potentiated by MAOIs, risking hypertensive crisis.

Which antibiotic is the FIRST-LINE prophylaxis for infective endocarditis in dental patients who are allergic to penicillin but can take oral medications?

Answer: Azithromycin 500 mg

Current AHA/ADA guidelines recommend azithromycin or clarithromycin 500 mg orally for penicillin-allergic patients requiring IE prophylaxis.

Flumazenil is used to reverse the sedative effects of which drug class?

Answer: Benzodiazepines

Flumazenil competitively antagonizes benzodiazepine receptors at the GABA-A complex, rapidly reversing sedation and respiratory depression.

Which drug interaction makes erythromycin dangerous when combined with certain antihistamines or antifungals?

Answer: Inhibition of CYP3A4 causing prolonged QT interval

Erythromycin inhibits CYP3A4, raising plasma levels of terfenadine or astemizole and risking fatal torsades de pointes via QT prolongation.