BCA Pharmacology of Anesthetic Agents 3 — Questions and Answers
Question 1: Which local anesthetic has the longest duration of action due to its high protein binding?
- Lidocaine
- Mepivacaine
- Chloroprocaine
- Bupivacaine (Correct answer)
Correct answer: Bupivacaine
Bupivacaine's approximately 95% protein binding prolongs its duration of action to 4-12 hours depending on block type.
Question 2: Propofol infusion syndrome is most associated with which metabolic derangement?
- Hypernatremia
- Metabolic alkalosis
- Severe metabolic acidosis with cardiac failure (Correct answer)
- Hypoglycemia
Correct answer: Severe metabolic acidosis with cardiac failure
Propofol infusion syndrome causes mitochondrial dysfunction leading to severe metabolic acidosis, rhabdomyolysis, and cardiac failure.
Question 3: Which volatile anesthetic is most associated with triggering malignant hyperthermia?
- Nitrous oxide
- Desflurane (Correct answer)
- Ketamine
- Propofol
Correct answer: Desflurane
All halogenated volatile anesthetics including desflurane can trigger malignant hyperthermia via uncontrolled RYR1 calcium release.
Question 4: The Hofmann elimination pathway of cisatracurium degradation means its duration is:
- Prolonged in renal failure
- Prolonged in hepatic failure
- Independent of organ function (Correct answer)
- Shortened by acidosis
Correct answer: Independent of organ function
Hofmann elimination is a spontaneous, temperature- and pH-dependent chemical degradation that does not rely on renal or hepatic function.
Question 5: Neostigmine reverses non-depolarizing neuromuscular blockade by:
- Competitively blocking nicotinic receptors
- Inhibiting acetylcholinesterase to increase ACh at the NMJ (Correct answer)
- Directly stimulating muscle nicotinic receptors
- Chelating the neuromuscular blocking agent
Correct answer: Inhibiting acetylcholinesterase to increase ACh at the NMJ
Neostigmine inhibits acetylcholinesterase, increasing ACh concentration at the neuromuscular junction to compete with the blocking agent.
Question 6: Which property of methohexital makes it preferred over thiopental for electroconvulsive therapy (ECT)?
- Longer duration of action
- Anticonvulsant properties
- Pro-convulsant properties that prolong seizure duration (Correct answer)
- Lower incidence of pain on injection
Correct answer: Pro-convulsant properties that prolong seizure duration
Methohexital lowers the seizure threshold and prolongs seizure duration, which is therapeutically beneficial in ECT.
Question 7: The primary advantage of sugammadex over neostigmine for neuromuscular blockade reversal is:
- Lower cost and wider availability
- Reversal of depolarizing blockade
- Rapid reversal even at deep levels of aminosteroidal blockade (Correct answer)
- Reversal without cardiovascular side effects requiring glycopyrrolate
Correct answer: Rapid reversal even at deep levels of aminosteroidal blockade
Sugammadex encapsulates rocuronium and vecuronium, enabling rapid reversal even at profound (PTC 1-2) levels of blockade where neostigmine is ineffective.
BCA Pharmacology of Anesthetic Agents 3
Which local anesthetic has the longest duration of action due to its high protein binding?