PEBC Pharmacology Basics 3

Question 1

Which route of drug administration completely bypasses first-pass hepatic metabolism?

Accepted Answer

Sublingual

Answer

Sublingual administration allows drug absorption directly into systemic circulation via the sublingual veins, completely bypassing first-pass hepatic metabolism.

Question 2

The volume of distribution (Vd) of a highly lipophilic drug is expected to be:

Accepted Answer

Very large, distributed into fat tissues

Answer

Highly lipophilic drugs partition extensively into fatty tissues, resulting in a very large apparent volume of distribution.

Question 3

An irreversible antagonist differs from a competitive antagonist in that it:

Accepted Answer

Decreases the maximum response (Emax) that can be achieved

Answer

An irreversible antagonist covalently or very tightly binds to the receptor, permanently reducing available receptors and lowering the achievable Emax.

Question 4

CYP3A4 induction by rifampin would most likely result in:

Accepted Answer

Reduced efficacy of drugs metabolized by CYP3A4

Answer

Rifampin induces CYP3A4, accelerating the metabolism of co-administered CYP3A4 substrates and reducing their plasma concentrations and efficacy.

Question 5

Which pharmacodynamic concept describes the concentration at which a drug produces 50% of its maximum effect?

Accepted Answer

EC50

Answer

EC50 (half-maximal effective concentration) is the drug concentration that produces 50% of the maximum pharmacological effect and reflects receptor potency.

PEBC - Pharmacy Examining Board of Canada Practice Test

PEBC - Pharmacy Examining Board of Canada Practice Test

PEBC Pharmacology Basics 3