FFICM Pharmacology Fundamentals 3

Question 1

Which mechanism best explains the tachyphylaxis seen with repeated doses of ephedrine?

Accepted Answer

Depletion of noradrenaline from presynaptic vesicles

Answer

Ephedrine acts indirectly by displacing noradrenaline from presynaptic terminals; repeated dosing depletes these stores, reducing each subsequent response.

Question 2

Rocuronium's neuromuscular blockade is antagonised by sugammadex via which mechanism?

Accepted Answer

Encapsulation of rocuronium molecules reducing free plasma concentration

Answer

Sugammadex is a modified gamma-cyclodextrin that encapsulates rocuronium (and vecuronium) in a tight complex, removing it from plasma and reversing blockade.

Question 3

A therapeutic drug monitoring level is taken 6 hours after an IV dose of vancomycin. The result is best described as:

Accepted Answer

An area-under-the-curve surrogate correlating with bactericidal activity

Answer

Modern vancomycin monitoring uses AUC/MIC ratio as the pharmacodynamic target; a mid-interval level can be used to estimate AUC when combined with another sample.

Question 4

Which pharmacodynamic parameter is most predictive of beta-lactam antibiotic efficacy?

Accepted Answer

Time above MIC (%T>MIC)

Answer

Beta-lactams exhibit time-dependent bactericidal activity; efficacy correlates with the proportion of the dosing interval during which free drug concentration exceeds the MIC.

Question 5

A critically ill patient develops prolonged paralysis after a single intubating dose of suxamethonium. The most likely cause is:

Accepted Answer

Pseudocholinesterase deficiency reducing hydrolysis of suxamethonium

Answer

Suxamethonium is hydrolysed by plasma pseudocholinesterase (butyrylcholinesterase); deficiency — genetic or acquired — prolongs the duration of blockade from minutes to hours.

(FFICM) Final Faculty of Intensive Care Medicine Practice Test

(FFICM) Final Faculty of Intensive Care Medicine Practice Test

FFICM Pharmacology Fundamentals 3