Pharmacokinetics and Pharmacodynamics Flashcards
6 cards from real Pharm.D. Doctor 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 6 Pharmacokinetics and Pharmacodynamics flashcards as text
Which equation is used to calculate drug clearance from area under the curve (AUC)?
Answer: CL = Dose / AUC
Clearance is calculated as CL = Dose / AUC (after IV dosing), relating the administered dose to total drug exposure.
Which type of drug interaction involves competition for the same plasma protein binding site?
Answer: Pharmacokinetic displacement
Pharmacokinetic displacement occurs when two drugs compete for the same plasma protein binding sites, potentially increasing free drug concentration of one.
The therapeutic index (TI) is calculated as:
Answer: TD50 / ED50
The therapeutic index is TD50 / ED50, representing the ratio of the toxic dose to the effective dose — a higher TI indicates a safer drug.
Renal clearance of a drug is primarily affected by which three processes?
Answer: Filtration, secretion, reabsorption
Renal drug clearance depends on glomerular filtration, active tubular secretion, and tubular reabsorption of the drug.
Which cytochrome P450 enzyme is most responsible for the metabolism of the majority of clinically used drugs?
Answer: CYP3A4
CYP3A4 is the most abundant hepatic CYP enzyme and is responsible for metabolizing approximately 50% of all clinically used drugs.
In a two-compartment pharmacokinetic model, the 'alpha' phase represents:
Answer: Distribution of drug into peripheral tissues
In a two-compartment model, the alpha (distribution) phase reflects rapid decline in plasma drug concentration due to drug distribution into peripheral tissues.