APC Pharmacology Fundamentals 2

Question 1

A drug with a narrow therapeutic index requires careful monitoring because:

Accepted Answer

The difference between therapeutic and toxic concentrations is small

Answer

A narrow therapeutic index means the toxic dose is close to the therapeutic dose, requiring careful dosing and monitoring.

Question 2

Which pharmacokinetic process describes the movement of a drug from the systemic circulation into tissues?

Accepted Answer

Distribution

Answer

Distribution refers to the reversible transfer of a drug from the bloodstream into tissues and organs throughout the body.

Question 3

A competitive antagonist differs from a non-competitive antagonist in that it:

Accepted Answer

Can be overcome by increasing the agonist concentration

Answer

A competitive antagonist competes with the agonist for the same binding site, and its effects can be overcome by increasing agonist concentration.

Question 4

The Vd (volume of distribution) of a highly protein-bound drug that remains in the plasma would be expected to be:

Accepted Answer

Very small (close to plasma volume, ~3–5 L)

Answer

Drugs that are highly plasma protein-bound and do not distribute into tissues have a small Vd approximating plasma volume.

Question 5

Which cytochrome P450 enzyme is responsible for metabolising the greatest number of clinically used drugs?

Accepted Answer

CYP3A4

Answer

CYP3A4 is the most abundant hepatic CYP enzyme and metabolises approximately 50% of all clinically used drugs.

(APC) Australian Pharmacy Council Practice Test