Pharmacology Pharmacodynamic Mechanisms 2

Question 1

Which term describes a drug that binds to a receptor and produces a submaximal response regardless of dose?

Accepted Answer

Partial agonist

Answer

Full agonist

Answer

Inverse agonist

Answer

Competitive antagonist

Question 2

An inverse agonist differs from a neutral antagonist in that an inverse agonist:

Accepted Answer

Reduces receptor activity below constitutive baseline

Answer

Blocks agonist binding without any effect of its own

Answer

Increases receptor affinity for endogenous ligands

Answer

Competes reversibly with agonists at the active site

Question 3

The Emax in a dose-response curve represents:

Accepted Answer

The maximum possible effect of a drug

Answer

The dose producing 50% of maximum effect

Answer

The slope of the linear portion of the curve

Answer

The drug concentration at receptor equilibrium

Question 4

Two drugs are said to be equieffective when they:

Accepted Answer

Require the same dose to achieve any response

Answer

Have the same molecular weight

Answer

Produce the same maximum effect

Answer

Bind to identical receptor subtypes

Question 5

Receptor reserve (spare receptors) means that:

Accepted Answer

Maximum effect is achieved before all receptors are occupied

Answer

Extra receptors are stored intracellularly until needed

Answer

Agonist affinity exceeds its intrinsic efficacy

Answer

Spare receptors have lower affinity than occupied ones

Question 6

Which pharmacodynamic parameter is most affected when a competitive antagonist is present?

Accepted Answer

EC50 of the agonist

Answer

Emax of the agonist

Answer

Hill coefficient of the agonist

Answer

Intrinsic efficacy of the agonist

Question 7

The phenomenon where prolonged receptor activation leads to decreased receptor number on the cell surface is called:

Accepted Answer

Receptor downregulation

Answer

Sensitization

Answer

Tachyphylaxis

Answer

Supersensitivity