MPharm Master of Pharmacy Master of Pharmacy: Pharmacokinetics and Pharmacodynamics 5

Question 1

The Emax model in pharmacodynamics relates drug effect to concentration. At concentrations much lower than EC50, the relationship approximates:

Accepted Answer

A linear relationship between concentration and effect

Answer

When C << EC50, the Emax equation simplifies to E ≈ Emax × C/EC50, which is a linear approximation.

Question 2

Population pharmacokinetics differs from classical PK analysis primarily in that it:

Accepted Answer

Quantifies between-subject variability and identifies covariates explaining it

Answer

Population PK uses nonlinear mixed-effects modeling (e.g., NONMEM) to characterize PK parameters and their variability across a patient population with sparse sampling.

Question 3

Which statement about drug protein binding is correct regarding pharmacokinetic implications?

Accepted Answer

Only the unbound fraction is available for distribution, metabolism, and receptor interaction

Answer

Only free (unbound) drug crosses membranes, interacts with receptors, and is available for metabolism and elimination.

Question 4

A patient with chronic kidney disease (CKD) stage 4 is prescribed a drug that is 80% renally eliminated unchanged. The expected outcome without dose adjustment is:

Accepted Answer

Drug accumulation and potential toxicity due to reduced elimination

Answer

CKD severely reduces renal clearance of drugs eliminated unchanged, causing accumulation and elevated plasma concentrations that may lead to toxicity.

Question 5

Mechanism-based (irreversible) enzyme inhibition differs from reversible inhibition because it:

Accepted Answer

Requires new enzyme synthesis for recovery of metabolic capacity

Answer

Mechanism-based inhibitors covalently inactivate the enzyme, so metabolic function is only restored when new enzyme protein is synthesized.

MPharm Master of Pharmacy Practice Test

MPharm Master of Pharmacy Practice Test

MPharm Master of Pharmacy Master of Pharmacy: Pharmacokinetics and Pharmacodynamics 5