PMC Help Session Questions

Which of the following best describes the pharmacodynamics of a drug?

• A relationship between drug concentration and time

• A relationship between drug concentration and effect

• A relationship between drug concentration and the rate of drug elimination

• A relationship between drug concentration and the rate of drug absorption

A relationship between drug concentration and effect

What term best describes the study of genetic variations among humans that lead to individual differences in drug response?

Pharmacogenetics

Which of the following is considered a “xenobiotic”? There may be more than one correct answer.

• Dopamine

• Estradiol

• Penicillin G

• Atorvastatin

• Insulin

Penicillin G and Atorvastatin

Which of the following drug-receptor bonds are considered irreversible?

• Covalent bonds

• Hydrogen bonds

• Ionic bonds

• Hydrophobic bonds

Covalent bonds

K_D (Equilibrium Dissociation Constant) is the concentration of free drug at which 50% of maximal drug-receptor binding is observed. K_D is a measure of which of the following?

• Intrinsic efficacy

• Drug specificity

• Drug efficacy

• Binding affinity

Binding affinity

True or False: E_max is a measure of efficacy

True

Do antagonists have intrinsic efficacy?

No

A drug that binds to the receptor and stabilizes all receptor molecules in the the R_i-D pool is referred to as an ____

Inverse agonist

Which of the following is most likely true about drugs that form weak bonds with their receptors?

• They are less selective in their binding than drugs that interact covalently with their receptors

• They cause more adverse effects than drugs that interact covalently with their receptors

• They are short-acting

They are short-acting

Which of the following ligands has equal affinity for binding to both the R_a and R_i conformations of the receptor molecule?

• Pharmacologic antagonist

• Inverse agonist

• Full agonist

• Partial agonist

Pharmacologic antagonist

Is noncovalent binding more or less selective than covalent binding?

More selective

EC₅₀ is the concentration of the drug required to produce 50% of its maximal effect at the receptor site. EC₅₀ is a measure of ____

Drug potency

E_max is the maximal pharmacologic effect a drug can produce at the receptor site. E_max is a measure of ____.

Drug efficacy

Which of the following ligands is able to reduce the constitutive activity of the receptor molecule?

• Pharmacologic antagonist

• Full agonist

• Inverse agonist

• Partial agonist

Inverse agonist

Drug A and Drug B are two new chiral drugs on the market that interact noncovalently with their receptors. Drug A has 5 chiral centers in its chemical structure; Drug B has only 1 chiral center. Which of the following is most likely true about these two drugs?

• Drug A is more selective in its binding to receptors in the body than Drug B

• Drug B is more selective in its binding to receptors in the body than Drug A

• Drug A and Drug B are equally selective in their binding to receptors in the body

Drug A is more selective in its binding to receptors in the body than Drug B

Which of the following is not true about an irreversible pharmacologic antagonist?

• It binds irreversibly to the receptor due to either covalent binding or extremely high affinity

• It's antagonistic action is not affected by the concentration of the endogenous agonist

• It's duration of action depends largely on the rate of its own elimination from the body

It's duration of action depends largely on the rate of its own elimination from the body

Which of the following is true about the degree of spareness of the receptor molecule in a particular tissue/cell type?

• The higher the degree of spareness, the more sensitive the tissue is to the drug

• The higher the degree of spareness, the lower the affinity of the drug for binding to the receptor

• The higher the degree of spareness, the lower the selectivity of the drug

• The higher the degree of spareness, the higher the Kd of the drug

The higher the degree of spareness, the more sensitive the tissue is to the drug

Drug X and Y have the same MOA. A dose of 5 mg of Drug X produces the same E_max as 500 mg of Drug Y. This suggests that:

• Drug Y is less efficacious than Drug X

• Drug X is about 100 times more potent than Drug Y

• Drug X is less toxic than Drug Y

• Drug X is more toxic than Drug Y

Drug X is about 100 times more potent than Drug Y

Quantal dose-response plots are used to determine which of the following?

• The therapeutic index of a drug

• The maximal efficacy of a drug

• The maximal binding of a drug

• The degree of spareness of the receptor molecule

The therapeutic index of a drug

Which of the following best describes the maximal efficacy of a drug at a particular receptor site?

• Emax

• ED50

• Bmax

• TD50

Emax

What can be determined from a Quantal dose-response plot?

Therapeutic index

In the absence of spare receptors, an irreversible noncompetitive pharmacologic antagonist is expected to acutely ____ the efficacy of an agonist.

reduce