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 drug with a large volume of distribution (Vd) is most likely doing which of the following?
Answer: Extensively distributed into peripheral tissues
A large Vd indicates the drug is widely distributed into tissues beyond the plasma compartment.
Which of the following best defines bioavailability?
Answer: The fraction of administered drug that reaches systemic circulation unchanged
Bioavailability (F) is the fraction of an administered dose that reaches systemic circulation in active form.
A drug undergoes significant first-pass metabolism. Which route of administration would BEST avoid this effect?
Answer: Intramuscular
Intramuscular injection delivers drug directly into systemic circulation, bypassing hepatic first-pass metabolism entirely.
What is the clinical significance of a drug with a high extraction ratio?
Answer: Its clearance is highly sensitive to changes in liver blood flow
High extraction ratio drugs (>0.7) have flow-limited clearance, meaning hepatic blood flow changes significantly affect drug elimination.
A patient has chronic kidney disease with a GFR of 20 mL/min. Which pharmacokinetic parameter is most directly affected?
Answer: Renal clearance
Renal clearance is directly reduced in CKD as glomerular filtration rate declines, prolonging drug half-life.
Which of the following is the correct formula for calculating drug half-life (t½)?
Answer: t½ = 0.693 × Vd / CL
Half-life is calculated as 0.693 multiplied by volume of distribution divided by clearance.
After how many half-lives does a drug reach approximately 97% of steady-state concentration?
Answer: 5
After 5 half-lives, a drug reaches approximately 97% of its steady-state concentration during continuous dosing.