NBDE Pharmacology and Therapeutics 2 — Questions and Answers
Question 1: A patient on warfarin requires dental extractions. Which analgesic is SAFEST to prescribe postoperatively?
- Aspirin 325 mg
- Ibuprofen 400 mg
- Acetaminophen 500 mg (Correct answer)
- Naproxen 500 mg
Correct answer: Acetaminophen 500 mg
Acetaminophen does not inhibit platelet function or significantly affect INR, making it the safest analgesic for patients on warfarin.
Question 2: Which local anesthetic has the LONGEST duration of action for dental nerve blocks?
- Lidocaine 2%
- Mepivacaine 3%
- Bupivacaine 0.5% (Correct answer)
- Prilocaine 4%
Correct 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.
Question 3: Methemoglobinemia is a known adverse effect of which local anesthetic at high doses?
- Lidocaine
- Articaine
- Prilocaine (Correct answer)
- Bupivacaine
Correct answer: Prilocaine
Prilocaine is metabolized to o-toluidine, which oxidizes hemoglobin to methemoglobin, causing methemoglobinemia at high doses.
Question 4: A patient taking a monoamine oxidase inhibitor (MAOI) requires local anesthesia. Which vasoconstrictor is CONTRAINDICATED?
- Epinephrine 1:100,000
- Levonordefrin (Correct answer)
- Felypressin
- Epinephrine 1:200,000
Correct answer: Levonordefrin
Levonordefrin (neo-cobefrin) is a sympathomimetic whose pressor effects are dangerously potentiated by MAOIs, risking hypertensive crisis.
Question 5: Which antibiotic is the FIRST-LINE prophylaxis for infective endocarditis in dental patients who are allergic to penicillin but can take oral medications?
- Clindamycin 600 mg
- Azithromycin 500 mg (Correct answer)
- Cephalexin 2 g
- Doxycycline 100 mg
Correct answer: Azithromycin 500 mg
Current AHA/ADA guidelines recommend azithromycin or clarithromycin 500 mg orally for penicillin-allergic patients requiring IE prophylaxis.
Question 6: Flumazenil is used to reverse the sedative effects of which drug class?
- Opioids
- Barbiturates
- Benzodiazepines (Correct answer)
- Antihistamines
Correct answer: Benzodiazepines
Flumazenil competitively antagonizes benzodiazepine receptors at the GABA-A complex, rapidly reversing sedation and respiratory depression.
Question 7: Which drug interaction makes erythromycin dangerous when combined with certain antihistamines or antifungals?
- Inhibition of CYP2D6 causing opioid toxicity
- Inhibition of CYP3A4 causing prolonged QT interval (Correct answer)
- Induction of CYP1A2 reducing drug efficacy
- Inhibition of P-glycoprotein causing nephrotoxicity
Correct 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.
NBDE Pharmacology and Therapeutics 2
A patient on warfarin requires dental extractions.
Which analgesic is SAFEST to prescribe postoperatively?