Master of Pharmacy: Pharmacokinetics and Pharmacodynamics Flashcards
7 cards from real MPharm Master of Pharmacy practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Master of Pharmacy: Pharmacokinetics and Pharmacodynamics flashcards as text
For a drug following two-compartment pharmacokinetics, the terminal elimination phase primarily reflects:
Answer: Redistribution from peripheral back to central compartment followed by elimination
In two-compartment models, the terminal beta phase represents slow redistribution of drug from peripheral tissues back to the central compartment, then elimination.
Which enzyme system is primarily responsible for Phase I oxidative metabolism of most drugs in the liver?
Answer: Cytochrome P450 (CYP) enzymes
Cytochrome P450 enzymes are the major Phase I metabolizing enzymes responsible for oxidation, reduction, and hydrolysis of most drugs.
Apparent clearance (CL/F) differs from true systemic clearance because it accounts for:
Answer: Incomplete bioavailability (F) after oral dosing
CL/F is apparent clearance calculated from oral dose data; dividing by F corrects for the fraction of dose that actually reaches systemic circulation.
A drug that acts as a partial agonist at a receptor will:
Answer: Activate the receptor but with lower intrinsic efficacy than a full agonist
Partial agonists bind and activate receptors but have lower intrinsic efficacy, producing a submaximal response even at receptor saturation.
Renal clearance of a drug exceeding glomerular filtration rate (GFR) suggests:
Answer: Active tubular secretion in addition to filtration
If CLrenal > GFR × fu, active tubular secretion must be occurring to add drug to the filtrate beyond what was filtered.
The Michaelis-Menten constant (Km) in drug metabolism represents:
Answer: The drug concentration at which metabolism rate is half of Vmax
Km is the substrate concentration at which the enzymatic reaction proceeds at half its maximum velocity (Vmax), reflecting enzyme-substrate affinity.
Tachyphylaxis is best described as:
Answer: Rapid decrease in response following repeated doses in a short time period
Tachyphylaxis is a rapid, short-term decrease in response to a drug after repeated administration, often due to receptor desensitization or depletion of mediators.