Pharmacology Pharmacodynamics and Mechanism of Action 2

Question 1

A drug with an EC50 of 2 nM is compared to one with an EC50 of 20 nM. Which statement is correct?

Accepted Answer

The 2 nM drug is more potent

Answer

The 20 nM drug is more potent

Answer

Both drugs have equal potency

Answer

EC50 measures efficacy, not potency

Question 2

Which receptor mechanism involves a ligand-gated ion channel that opens within milliseconds of agonist binding?

Accepted Answer

Type I (ionotropic)

Answer

Type II (metabotropic)

Answer

Type IV (nuclear receptor)

Answer

Type III (tyrosine kinase)

Question 3

A drug that binds to an allosteric site and enhances agonist binding without activating the receptor itself is called a:

Accepted Answer

Positive allosteric modulator

Answer

Competitive antagonist

Answer

Inverse agonist

Answer

Partial agonist

Question 4

Which phenomenon describes the decreased response to a drug after repeated dosing due to receptor internalization?

Accepted Answer

Down-regulation

Answer

Sensitization

Answer

Synergism

Answer

Supersensitivity

Question 5

The Schild equation is used to characterize which type of drug interaction?

Accepted Answer

Competitive antagonism

Answer

Non-competitive antagonism

Answer

Pharmacokinetic drug interactions

Answer

Irreversible agonism

Question 6

A drug produces a maximal response of only 60% compared to a full agonist at the same receptor. This drug is best described as:

Accepted Answer

A partial agonist

Answer

A competitive antagonist

Answer

A pharmacological antagonist

Answer

A neutral antagonist

Question 7

Which second messenger is directly produced by adenylyl cyclase activation following Gs protein stimulation?

Accepted Answer

Cyclic AMP (cAMP)

Answer

Inositol trisphosphate (IP3)

Answer

Diacylglycerol (DAG)

Answer

Cyclic GMP (cGMP)