Pharmacodynamics — General Pharmacology

Pharmacodynamics MCQs: practice questions

Sample Pharmacodynamics multiple-choice questions from General Pharmacology.

1. Two drugs act at the same receptor. Drug X produces the same maximal effect as drug Y but at a lower concentration. Drug X is more:

   • A. Selective for renal elimination
   • B. Potent
   • C. Toxic
   • D. Bioavailable
   • E. Efficacious

2. A patient develops a progressively smaller response to repeated doses of a drug over a short period. This phenomenon is called:

   • A. Hypersensitivity
   • B. Idiosyncrasy
   • C. First-pass metabolism
   • D. Bioavailability
   • E. Tachyphylaxis

3. Which receptor mechanism generally produces the most rapid cellular response?

   • A. Cytosolic enzyme induction
   • B. Intracellular steroid receptor
   • C. Nuclear thyroid receptor
   • D. DNA-binding transcription factor
   • E. Ligand-gated ion channel

4. A drug that produces a maximal response when occupying receptors has what property?

   • A. Low efficacy
   • B. No intrinsic activity
   • C. High efficacy
   • D. Low bioavailability
   • E. High clearance

5. A drug produces a biologic response by binding to a receptor at a site distinct from the agonist-binding site and preventing receptor activation. This is:

   • A. Pharmacokinetic enhancement
   • B. Competitive agonism
   • C. Partial agonism
   • D. Chemical antagonism
   • E. Noncompetitive antagonism

6. A drug's dose-response curve has the same maximum effect as another drug but is shifted to the right. The right-shifted drug is:

7. A reversible competitive antagonist is added to a full agonist. What is the expected change in the agonist dose-response curve?

8. A drug produces a response even though it has lower intrinsic activity than the endogenous ligand. It is best classified as:

9. Which parameter is most closely related to receptor affinity?

10. Which statement about an agonist is correct?

11. A drug has an ED50 of 2 mg and another has an ED50 of 20 mg, with equal maximal efficacy at the same receptor. Which is more potent?

12. The therapeutic index is classically expressed as:

13. A receptor activates phospholipase C through Gq. Which intracellular signaling pair is generated from PIP2?

14. A drug has high receptor affinity but low intrinsic activity. It is most likely a:

15. A patient receives a drug with an unusually small therapeutic index. Which approach is most appropriate?

16. A receptor activates adenylyl cyclase through a stimulatory G protein. Which second messenger increases?

17. A drug has a very narrow therapeutic index. What does this imply?

18. An antagonist binds reversibly to the same receptor site as an agonist. Which term best describes this interaction?

19. A drug binds a receptor but has zero intrinsic activity. It is best described as:

20. Which statement best explains why a reversible competitive antagonist does not reduce maximal agonist response?

21. Which change would most likely make a drug appear more potent without changing its efficacy?

22. Which receptor class typically alters gene transcription and therefore has a relatively slow onset of action?

23. A receptor is activated by binding of a drug and then directly opens an ion channel. This receptor is best classified as:

24. A drug activates a receptor but produces only 40% of the maximal response even when all receptors are occupied. What property does this demonstrate?

25. A dose-response curve reaches a plateau despite further increases in drug concentration. The plateau primarily represents:

26. A noncompetitive antagonist is added to an agonist. Which change is expected?

27. Cortisol produces many of its effects by binding to:

28. A reversible competitive antagonist increases the agonist ED50 but does not change its maximum response. What happens to potency?

29. Which feature distinguishes efficacy from potency?

30. A partial agonist is administered in the presence of a full agonist acting at the same receptor. What may occur?