Pharmacology Pharmacokinetic Principles 3

Question 1

Which process describes passive movement of a drug from an area of high concentration to low concentration across a membrane without energy expenditure?

Accepted Answer

Passive diffusion

Answer

Passive diffusion is the most common mechanism of drug absorption and requires no energy, driven solely by concentration gradients.

Question 2

A drug is 90% plasma protein-bound. If a second drug displaces it, which fraction of the drug becomes pharmacologically active?

Accepted Answer

The free (unbound) fraction

Answer

Only the free (unbound) fraction of a drug is pharmacologically active and able to exert effects at target sites.

Question 3

What does zero-order kinetics mean in drug elimination?

Accepted Answer

A constant amount of drug is eliminated per unit time

Answer

Zero-order kinetics means a fixed amount (not fraction) of drug is eliminated per unit time, regardless of plasma concentration.

Question 4

Which of the following drugs is most likely to have unpredictable toxicity if renal function declines?

Accepted Answer

Digoxin (renally cleared)

Answer

Digoxin is predominantly renally eliminated, so reduced GFR leads to drug accumulation and potential toxicity.

Question 5

The area under the plasma concentration-time curve (AUC) is a measure of:

Accepted Answer

Total drug exposure over time

Answer

AUC represents total systemic drug exposure integrated over time and is used to assess bioavailability and calculate clearance.

Pharmacology Practice Test

Pharmacology Practice Test

Pharmacology Pharmacokinetic Principles 3