NBDE Pharmacology and Pain Control 3 — Questions and Answers
Question 1: Which local anesthetic has the longest duration of action and is commonly used for procedures requiring prolonged anesthesia?
- Lidocaine
- Mepivacaine
- Bupivacaine (Correct answer)
- Prilocaine
Correct answer: Bupivacaine
Bupivacaine has the highest lipid solubility and protein binding, producing durations of 4–9 hours and making it suitable for lengthy surgical procedures.
Question 2: Nitrous oxide produces analgesia primarily by:
- Blocking sodium channels in peripheral nerves
- Stimulating opioid receptors in the central nervous system (Correct answer)
- Inhibiting GABA reuptake
- Blocking NMDA receptors only
Correct answer: Stimulating opioid receptors in the central nervous system
Nitrous oxide activates endogenous opioid receptors in the brainstem and spinal cord, contributing to its analgesic and anxiolytic effects.
Question 3: A child requires sedation for dental treatment. Which oral sedative is FDA-approved and commonly used in pediatric dentistry?
- Triazolam
- Midazolam (Correct answer)
- Chloral hydrate
- Diazepam
Correct answer: Midazolam
Oral midazolam is widely used for pediatric dental sedation due to its rapid onset, effective sedation, and amnestic properties with a manageable safety profile.
Question 4: COX-2 selective inhibitors like celecoxib are preferred over non-selective NSAIDs primarily because they:
- Provide superior analgesia
- Have lower risk of gastrointestinal ulceration (Correct answer)
- Are more effective anti-inflammatory agents
- Have longer half-lives
Correct answer: Have lower risk of gastrointestinal ulceration
COX-2 inhibitors spare gastric prostaglandin synthesis (COX-1 mediated), reducing the risk of gastrointestinal mucosal damage compared to non-selective NSAIDs.
Question 5: Which opioid is a partial mu-receptor agonist and can precipitate withdrawal in opioid-dependent patients?
- Fentanyl
- Buprenorphine (Correct answer)
- Oxycodone
- Hydromorphone
Correct answer: Buprenorphine
Buprenorphine is a partial agonist with very high mu-receptor affinity; it displaces full agonists and precipitates acute withdrawal in opioid-dependent individuals.
Question 6: The maximum safe dose of lidocaine WITH epinephrine in a healthy adult is approximately:
- 3 mg/kg (not to exceed 200 mg)
- 4.4 mg/kg (not to exceed 300 mg)
- 7 mg/kg (not to exceed 500 mg) (Correct answer)
- 10 mg/kg (not to exceed 700 mg)
Correct answer: 7 mg/kg (not to exceed 500 mg)
Epinephrine's vasoconstrictive effect slows absorption and allows a higher maximum dose of lidocaine—7 mg/kg up to 500 mg—compared to 4.4 mg/kg without epinephrine.
Question 7: Codeine's analgesic effect depends on its hepatic conversion to morphine by which enzyme?
- CYP2C9
- CYP3A4
- CYP2D6 (Correct answer)
- CYP1A2
Correct answer: CYP2D6
CYP2D6 O-demethylates codeine to morphine; poor metabolizers receive minimal analgesia while ultra-rapid metabolizers risk toxic morphine levels.
NBDE Pharmacology and Pain Control 3
Which local anesthetic has the longest duration of action and is commonly used for procedures requiring prolonged anesthesia?