FANZCA FANZCA Clinical Pharmacology and Anesthesia 1 — Questions and Answers
Question 1: Which volatile anesthetic agent has the lowest blood-gas partition coefficient, resulting in the fastest induction and emergence?
- Desflurane (Correct answer)
- Sevoflurane
- Isoflurane
- Halothane
Correct answer: Desflurane
Desflurane has a blood-gas partition coefficient of approximately 0.45, the lowest among commonly used volatile agents, enabling the fastest induction and emergence.
Question 2: What is the mechanism of action of succinylcholine as a neuromuscular blocking agent?
- Competitive antagonism at nicotinic acetylcholine receptors
- Depolarizing agonism at nicotinic acetylcholine receptors (Correct answer)
- Inhibition of acetylcholinesterase at the neuromuscular junction
- Blockade of voltage-gated sodium channels in motor neurons
Correct answer: Depolarizing agonism at nicotinic acetylcholine receptors
Succinylcholine acts as a depolarizing agent by mimicking acetylcholine and persistently binding to nicotinic receptors, causing initial fasciculations followed by flaccid paralysis.
Question 3: Which opioid is most commonly associated with chest wall rigidity ('wooden chest syndrome') when administered rapidly in high doses?
- Morphine
- Fentanyl (Correct answer)
- Hydromorphone
- Codeine
Correct answer: Fentanyl
Fentanyl, particularly when given in large doses rapidly, is the opioid most classically associated with truncal rigidity that can impair ventilation.
Question 4: What is the primary reason propofol produces pain on injection when administered through a peripheral IV?
- Its highly alkaline pH irritates the vein
- Its lipid emulsion vehicle activates bradykinin and free nerve endings (Correct answer)
- It causes direct endothelial histamine release
- Its high osmolality damages vessel walls
Correct answer: Its lipid emulsion vehicle activates bradykinin and free nerve endings
Propofol's lipid emulsion can activate the kinin cascade and stimulate free nerve endings in the vessel wall, causing the characteristic injection pain.
Question 5: Which reversal agent is used to antagonize non-depolarizing neuromuscular blockers by forming a tight inclusion complex, specifically targeting rocuronium and vecuronium?
- Neostigmine
- Sugammadex (Correct answer)
- Pyridostigmine
- Edrophonium
Correct answer: Sugammadex
Sugammadex is a modified gamma-cyclodextrin that encapsulates rocuronium and vecuronium molecules, providing rapid and complete reversal of neuromuscular blockade.
Question 6: Which local anesthetic is most associated with cardiotoxicity and has a narrow therapeutic window compared to newer long-acting agents?
- Ropivacaine
- Levobupivacaine
- Bupivacaine (Correct answer)
- Lidocaine
Correct answer: Bupivacaine
Bupivacaine's racemic mixture has high cardiotoxicity due to its prolonged binding to cardiac sodium channels, leading to the development of single-enantiomer alternatives.
FANZCA FANZCA Clinical Pharmacology and Anesthesia 1
Which volatile anesthetic agent has the lowest blood-gas partition coefficient, resulting in the fastest induction and emergence?