Pharmacokinetics — General Pharmacology

Pharmacokinetics MCQs: practice questions

Sample Pharmacokinetics multiple-choice questions from General Pharmacology.

1. A drug has a very high hepatic extraction ratio. Which property is most likely to strongly influence its hepatic clearance?

   • A. Urinary pH
   • B. Bone mineral density
   • C. GFR alone
   • D. Plasma sodium concentration
   • E. Hepatic blood flow

2. A patient is given a drug that is 90% plasma protein bound. A second drug displaces it from albumin without changing its metabolism or renal function. What is the immediate effect?

   • A. Renal secretion stops
   • B. The Vd must decrease to zero
   • C. The free fraction increases
   • D. The drug becomes completely inactive
   • E. Bioavailability becomes 100%

3. Which statement best describes hepatic first-pass metabolism?

   • A. Portal entry before systemic circulation
   • B. It always increases oral bioavailability
   • C. It occurs only with intravenous administration
   • D. Drug is metabolized only after renal excretion
   • E. It prevents any drug from entering the systemic circulation

4. Which route provides the most predictable systemic bioavailability?

   • A. Rectal
   • B. Intravenous
   • C. Oral
   • D. Subcutaneous
   • E. Inhaled

5. A drug is eliminated by zero-order kinetics at therapeutic concentrations. Which statement is correct?

   • A. A constant amount is eliminated per unit time
   • B. A constant fraction is eliminated per unit time
   • C. Half-life is independent of concentration
   • D. Clearance increases linearly with concentration
   • E. The drug must be eliminated by filtration only

6. A patient receives a drug with a Vd of 100 L. Which statement is most appropriate?

7. A drug is completely cleared by renal filtration and is 100% free in plasma. Its renal clearance would be expected to approximate which value in a healthy adult?

8. A patient receives 400 mg of a drug intravenously. The initial plasma concentration is 8 mg/L. What is the apparent volume of distribution?

9. Which drug property most facilitates passage across the blood-brain barrier by passive diffusion?

10. A patient receives an oral drug at a constant dosing rate. Bioavailability increases while clearance remains unchanged. What happens to average steady-state plasma concentration?

11. A drug has an oral bioavailability of 0.50. If 200 mg is administered orally, how much reaches the systemic circulation unchanged?

12. A drug's clearance decreases while its Vd remains unchanged. What happens to its elimination half-life?

13. A weak acid is present in the renal tubular fluid. Which intervention increases its urinary excretion by ion trapping?

14. A patient requires an immediate therapeutic plasma concentration of a drug with a very long half-life. Which strategy is most appropriate?

15. Which renal process is directly reduced when a drug becomes extensively bound to plasma proteins?

16. A drug has a Vd of 20 L and a plasma concentration of 5 mg/L after IV administration. What amount of drug is present in the body according to the Vd relationship?

17. A patient with severe renal failure receives a drug with a narrow therapeutic index that is normally eliminated primarily by the kidneys. What change is most likely?

18. A drug has a half-life of 8 hours and follows first-order kinetics. Approximately what fraction remains after 24 hours?

19. A drug is given intravenously as a single bolus. Which pharmacokinetic parameter is bypassed completely by this route?

20. Which tissue receives drug most rapidly immediately after IV administration?

21. A drug is highly bound to plasma albumin. Which fraction is most readily available to diffuse into tissues and undergo filtration?

22. A patient takes an oral drug that undergoes extensive first-pass hepatic metabolism. Which administration route would most directly bypass this effect?

23. A drug has a half-life of 6 hours. After approximately how long will more than 95% of the drug be eliminated if first-order kinetics apply?

24. A drug has a clearance of 5 L/hour and a desired steady-state plasma concentration of 4 mg/L. What maintenance dose rate is required?

25. Which change would increase the apparent volume of distribution of a highly lipid-soluble drug?

26. Which characteristic most strongly favors rapid absorption of a drug from the gastrointestinal tract?

27. A drug follows first-order elimination. What does this mean?

28. A drug is administered continuously at a constant rate. Approximately how long is required to reach 90% of its eventual steady-state concentration?

29. Which parameter is most directly responsible for the duration required to reach steady state during repeated dosing?

30. Which pharmacokinetic equation correctly describes renal clearance?