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
A patient is a CYP2D6 poor metabolizer. What is the most likely clinical consequence when prescribed codeine?
Answer: Reduced conversion to morphine and diminished analgesia
Codeine requires CYP2D6 to convert it to active morphine; poor metabolizers produce little morphine and experience inadequate pain relief.
Which of the following conditions would most likely INCREASE the free fraction of a highly protein-bound drug?
Answer: Hypoalbuminemia from liver cirrhosis
Hypoalbuminemia reduces available binding sites, increasing the unbound (free) drug fraction and risk of toxicity.
Tmax in a pharmacokinetic curve refers to:
Answer: The time at which maximum drug concentration occurs
Tmax is the time point at which the peak plasma concentration (Cmax) is reached after drug administration.
Why is intravenous administration considered the gold standard for 100% bioavailability?
Answer: IV drugs are delivered directly into systemic circulation with no absorption barrier
Intravenous administration places drug directly into the bloodstream, completely bypassing absorption and first-pass metabolism.
A drug has nonlinear (saturable) pharmacokinetics. Which of the following is expected at supratherapeutic doses?
Answer: Small dose increases cause disproportionately large increases in plasma levels
When metabolic enzymes become saturated, small increases in dose cause disproportionate plasma level rises, increasing toxicity risk.
Which of the following best describes renal tubular secretion in pharmacokinetics?
Answer: Active transport of drug from peritubular capillaries into the tubule lumen
Tubular secretion actively transports drug from blood into the tubule lumen via OAT/OCT transporters, independent of filtration.
Which pharmacokinetic parameter is most useful for calculating a maintenance dose to achieve a target steady-state concentration?
Answer: Clearance
Maintenance dose rate = Clearance × target Css; clearance determines how fast the drug must be replaced to maintain steady state.