Pharmacology Fundamentals Flashcards

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

Answer: The difference between therapeutic and toxic concentrations is small

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

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

Answer: Distribution

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

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

Answer: Can be overcome by increasing the agonist concentration

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

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

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

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

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

Answer: CYP3A4

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

An inverse agonist at a receptor will:

Answer: Produce an effect opposite to that of the agonist

An inverse agonist binds the receptor and produces an effect opposite in direction to that of the agonist, reducing basal receptor activity.

Phase II drug metabolism reactions primarily involve:

Answer: Conjugation of the drug or its metabolite with an endogenous molecule

Phase II reactions are conjugation reactions (e.g., glucuronidation, sulfation, acetylation) that increase water solubility to facilitate excretion.