Pharmacokinetic Principles Flashcards
7 cards from real Pharmacology practice questions. Tap to flip, then mark Knew It or Still Learning — missed cards come back until you master them.
Read the first 7 Pharmacokinetic Principles flashcards as text
Which process describes passive movement of a drug from an area of high concentration to low concentration across a membrane without energy expenditure?
Answer: Passive diffusion
Passive diffusion is the most common mechanism of drug absorption and requires no energy, driven solely by concentration gradients.
A drug is 90% plasma protein-bound. If a second drug displaces it, which fraction of the drug becomes pharmacologically active?
Answer: The free (unbound) fraction
Only the free (unbound) fraction of a drug is pharmacologically active and able to exert effects at target sites.
What does zero-order kinetics mean in drug elimination?
Answer: A constant amount of drug is eliminated per unit time
Zero-order kinetics means a fixed amount (not fraction) of drug is eliminated per unit time, regardless of plasma concentration.
Which of the following drugs is most likely to have unpredictable toxicity if renal function declines?
Answer: Digoxin (renally cleared)
Digoxin is predominantly renally eliminated, so reduced GFR leads to drug accumulation and potential toxicity.
The area under the plasma concentration-time curve (AUC) is a measure of:
Answer: Total drug exposure over time
AUC represents total systemic drug exposure integrated over time and is used to assess bioavailability and calculate clearance.
A loading dose is used clinically to:
Answer: Rapidly achieve therapeutic plasma concentrations
A loading dose achieves therapeutic concentrations quickly without waiting for 4-5 half-lives of accumulation.
Enterohepatic recirculation of a drug leads to:
Answer: Prolonged drug action due to reabsorption from the gut
Enterohepatic recirculation involves biliary excretion and intestinal reabsorption, prolonging the drug's effect and half-life.