PEBC Pharmacology Basics 4

Question 1

Tachyphylaxis refers to:

Accepted Answer

Rapid decrease in drug response following repeated administration

Answer

Tachyphylaxis is a rapid, short-term decrease in response to a drug after repeated doses, often due to receptor desensitization or depletion of mediators.

Question 2

A drug with high plasma protein binding would be expected to have:

Accepted Answer

Reduced volume of distribution

Answer

Highly protein-bound drugs have less free drug in plasma to distribute into tissues, resulting in a lower apparent volume of distribution.

Question 3

Which of the following best describes a prodrug?

Accepted Answer

An inactive compound converted to an active metabolite in the body

Answer

A prodrug is pharmacologically inactive and must be metabolized (typically by the liver) to an active form to exert its therapeutic effect.

Question 4

The Henderson-Hasselbalch equation is used in pharmacology primarily to:

Accepted Answer

Predict the degree of drug ionization at a given pH

Answer

The Henderson-Hasselbalch equation relates pH, pKa, and ionization, allowing prediction of the proportion of ionized vs. non-ionized drug at a given pH.

Question 5

Enteric coating on a tablet is designed primarily to:

Accepted Answer

Prevent dissolution until the tablet reaches the small intestine

Answer

Enteric coating resists gastric acid and dissolves only at the higher pH of the intestine, protecting acid-labile drugs or the gastric mucosa from irritating compounds.

PEBC - Pharmacy Examining Board of Canada Practice Test

PEBC - Pharmacy Examining Board of Canada Practice Test

PEBC Pharmacology Basics 4