DMD - Doctor of Medicine in Dentistry Pharmacology and Therapeutics Questions and Answers — Questions and Answers
Question 1: A 45-year-old male patient with a history of hypertension and taking lisinopril presents for a tooth extraction. He reports significant dental anxiety. Which of the following anxiolytic agents would be most appropriate to administer, considering his medical history?
- Diazepam
- Triazolam
- Hydroxyzine
- Lorazepam (Correct answer)
Correct answer: Lorazepam
Lorazepam is an intermediate-acting benzodiazepine that is metabolized primarily through glucuronidation, which is less affected by liver function and has fewer drug interactions compared to diazepam and triazolam, which undergo oxidative metabolism. This makes it a safer choice for patients with potential systemic health issues or those on multiple medications. Hydroxyzine, an antihistamine, is less effective for moderate to severe dental anxiety.
Question 2: A patient undergoing a routine dental cleaning suddenly complains of chest pain, shortness of breath, and pain radiating to their left arm. You suspect a myocardial infarction. After activating emergency medical services, what is the most appropriate initial pharmacological intervention?
- Administer a sublingual dose of nitroglycerin.
- Provide a chewable 325 mg aspirin. (Correct answer)
- Administer supplemental oxygen.
- Inject 0.3 mg of epinephrine intramuscularly.
Correct answer: Provide a chewable 325 mg aspirin.
For a suspected myocardial infarction, administering a chewable 162-325 mg aspirin is a critical first step to inhibit platelet aggregation. While supplemental oxygen and nitroglycerin are also important components of management, the antiplatelet effect of aspirin is paramount in the initial phase. Epinephrine is indicated for anaphylaxis, not a myocardial infarction.
Question 3: Which of the following local anesthetics is classified as an ester and is more likely to cause an allergic reaction due to its metabolism to para-aminobenzoic acid (PABA)?
- Lidocaine
- Mepivacaine
- Articaine
- Procaine (Correct answer)
Correct answer: Procaine
Procaine is an ester-type local anesthetic. Ester anesthetics are metabolized in the plasma by pseudocholinesterase to para-aminobenzoic acid (PABA), which is a known allergen for some individuals. Lidocaine, mepivacaine, and articaine are all amide-type local anesthetics, which are metabolized in the liver and are much less likely to cause allergic reactions.
Question 4: A patient presents with a severe, localized odontogenic infection with swelling and purulence. They have a known allergy to penicillin, which resulted in anaphylaxis. Which of the following antibiotics would be the most appropriate alternative?
- Amoxicillin
- Cephalexin
- Clindamycin (Correct answer)
- Tetracycline
Correct answer: Clindamycin
Clindamycin is an effective antibiotic for many odontogenic infections and is a standard alternative for patients with a severe penicillin allergy. Amoxicillin is a penicillin-class antibiotic and is contraindicated. Cephalexin, a cephalosporin, has a potential for cross-reactivity in patients with a history of anaphylaxis to penicillin and should be avoided. Tetracycline is generally not the first-choice antibiotic for acute odontogenic infections.
Question 5: A patient taking warfarin for atrial fibrillation requires a surgical extraction. The dentist receives a recent INR reading of 4.5. What is the most appropriate course of action?
- Proceed with the extraction using local hemostatic measures.
- Administer vitamin K to reverse the effects of warfarin before the procedure.
- Postpone the procedure and consult with the patient's physician to adjust the warfarin dose. (Correct answer)
- Advise the patient to stop taking warfarin for two days prior to the extraction.
Correct answer: Postpone the procedure and consult with the patient's physician to adjust the warfarin dose.
An INR of 4.5 is significantly elevated above the therapeutic range for most indications and indicates a high risk of bleeding. The safest course of action is to postpone the elective surgical procedure and consult with the prescribing physician to manage the patient's anticoagulation therapy. Proceeding with the extraction, administering vitamin K without physician consultation, or advising the patient to alter their medication regimen independently are all inappropriate and potentially dangerous.
Question 6: Which of the following best describes the mechanism of action for nonsteroidal anti-inflammatory drugs (NSAIDs) like ibuprofen in managing dental pain?
- Agonism of mu-opioid receptors in the central nervous system.
- Inhibition of cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis. (Correct answer)
- Blockade of sodium channels in peripheral nerves.
- Increasing the reuptake of serotonin and norepinephrine.
Correct answer: Inhibition of cyclooxygenase (COX) enzymes, reducing prostaglandin synthesis.
NSAIDs exert their analgesic, anti-inflammatory, and antipyretic effects by inhibiting the cyclooxygenase (COX-1 and COX-2) enzymes. This action blocks the conversion of arachidonic acid to prostaglandins, which are key mediators of pain and inflammation at the site of injury. Opioid agonists act on mu-opioid receptors, local anesthetics block sodium channels, and increasing serotonin/norepinephrine reuptake is the mechanism of certain antidepressants.
DMD - Doctor of Medicine in Dentistry Pharmacology and Therapeutics Questions and Answers
A 45-year-old male patient with a history of hypertension and taking lisinopril presents for a tooth extraction.
He reports significant dental anxiety.
Which of the following anxiolytic agents would be most appropriate to administer, considering his medical history?