Pharmacodynamics/Pharmacogenetics Practice MCQs- DPAP Fall 2026

Pharmacodynamics is best defined as:

A. What the body does to the drug

B. What the drug does to the body

C. Drug metabolism

D. Drug elimination

B. What the drug does to the body

Which statement best describes a full agonist?

A. Has affinity but no efficacy

B. Produces a submaximal response

C. Produces a maximal response

D. Irreversibly blocks receptors

C. Produces a maximal response

Which characteristic is shared by both full agonists and partial agonists?

A. No efficacy

B. Affinity for receptors

C. Irreversible binding

D. Complete receptor blockade

B. Affinity for receptors

Compared with a full agonist, a partial agonist:

A. Has no receptor affinity

B. Produces less than a maximal response

C. Always acts as a competitive antagonist

D. Has greater efficacy

B. Produces less than a maximal response

Which of the following is an example of a full agonist from the lecture?

A. Naloxone

B. Buprenorphine

C. Methadone

D. Aspirin

C. Methadone

Which of the following is an example of a partial agonist?

A. Methadone

B. Naloxone

C. Buprenorphine

D. Acetaminophen

C. Buprenorphine

An antagonist has:

A. Affinity and efficacy

B. Efficacy but no affinity

C. Affinity but no efficacy

D. Neither affinity nor efficacy

C. Affinity but no efficacy

Which drug is an example of a competitive antagonist?

A. Methadone

B. Buprenorphine

C. Naloxone

D. Morphine

C. Naloxone

The effect of a competitive antagonist can usually be overcome by:

A. Increasing the agonist concentration

B. Stopping all medications

C. Blocking the receptor irreversibly

D. Increasing protein binding

A. Increasing the agonist concentration

A noncompetitive antagonist:

A. Binds reversibly

B. Produces maximal efficacy

C. Cannot be overcome with additional agonist

D. Has no receptor affinity

C. Cannot be overcome with additional agonist

An inverse agonist:

A. Stimulates the receptor fully

B. Reduces receptor activity below basal levels

C. Produces partial receptor stimulation

D. Has no receptor activity

B. Reduces receptor activity below basal levels

Repeated exposure to an agonist may result in:

A. Up-regulation

B. Down-regulation

C. Increased receptor sensitivity only

D. Increased efficacy

B. Down-regulation

Which phenomenon occurs when receptor numbers decrease after repeated agonist exposure?

A. Potentiation

B. Synergism

C. Down-regulation

D. Up-regulation

C. Down-regulation

Tolerance refers to:

A. Immediate allergic reaction

B. Increased effect with repeated use

C. Reduced response to the same dose over time

D. A type of pharmacokinetic interaction

C. Reduced response to the same dose over time

Tachyphylaxis is best described as:

A. Rapid loss of responsiveness

B. Delayed hypersensitivity

C. Increased metabolism

D. Increased receptor synthesis

A. Rapid loss of responsiveness

Repeated exposure to an antagonist may produce:

A. Down-regulation

B. Tachyphylaxis

C. Up-regulation

D. Desensitization only

C. Up-regulation

Abrupt discontinuation of a beta blocker may lead to tachycardia because of:

A. First-pass metabolism

B. Up-regulation

C. Zero-order kinetics

D. Reduced affinity

B. Up-regulation

The dose-response relationship describes:

A. Drug metabolism only

B. Drug elimination only

C. Relationship between dose and magnitude of response

D. Drug distribution only

C. Relationship between dose and magnitude of response

Potency refers to:

A. Maximum response achievable

B. Amount of drug needed to produce a given effect

C. Duration of drug effect

D. Therapeutic index

B. Amount of drug needed to produce a given effect

A more potent drug generally:

A. Requires a larger dose

B. Requires a smaller dose for the same effect

C. Has greater efficacy

D. Has more toxicity

B. Requires a smaller dose for the same effect

Efficacy refers to:

A. Maximum response a drug can produce

B. Affinity for a receptor

C. Drug half-life

D. Drug elimination

A. Maximum response a drug can produce

Which statement is true regarding potency and efficacy?

A. More potent drugs are always more efficacious

B. Potency predicts efficacy

C. Potency and efficacy are not the same concept

D. Efficacy determines receptor affinity

C. Potency and efficacy are not the same concept

Which drug type has the highest efficacy?

A. Antagonist

B. Partial agonist

C. Full agonist

D. Inverse agonist

C. Full agonist

An antagonist has what level of efficacy?

A. Maximal

B. Partial

C. Variable

D. None

D. None

ED50 refers to:

A. Toxic dose in 50% of patients

B. Effective dose in 50% of patients

C. Dose producing 50% of maximum effect

D. Dose that blocks 50% of receptors

C. Dose producing 50% of maximum effect

An adverse drug reaction (ADR) is:

A. Any medication error

B. A noxious unintended response at normal doses

C. A drug overdose

D. Drug abuse

B. A noxious unintended response at normal doses

Which type of ADR is usually predictable and dose-related?

A. Type A

B. Type B

C. Allergic

D. Idiosyncratic

A. Type A

Which type of ADR is generally unpredictable?

A. Type A

B. Type B

C. Dose-related

D. Expected

B. Type B

An IgE-mediated drug allergy is classified as:

A. Type I hypersensitivity

B. Type II hypersensitivity

C. Type III hypersensitivity

D. Type IV hypersensitivity

A. Type I hypersensitivity

Which reaction is most consistent with Type I hypersensitivity?

A. Contact dermatitis

B. Serum sickness

C. Anaphylaxis

D. Hemolytic anemia

C. Anaphylaxis

Drug-induced hemolytic anemia is associated with:

A. Type I

B. Type II

C. Type III

D. Type IV

B. Type II

Serum sickness is classified as:

A. Type I

B. Type II

C. Type III

D. Type IV

C. Type III

Contact dermatitis is most consistent with:

A. Type I

B. Type II

C. Type III

D. Type IV

D. Type IV

Type IV hypersensitivity reactions are primarily mediated by:

A. IgE

B. IgG

C. Immune complexes

D. T cells

D. T cells

A tetracycline interacting with iron supplements is an example of:

A. Pharmacodynamic interaction

B. Allergic reaction

C. Pharmacokinetic interaction affecting absorption

D. Synergism

C. Pharmacokinetic interaction affecting absorption

Competition between drugs for albumin binding is a pharmacokinetic interaction affecting:

A. Absorption

B. Distribution

C. Metabolism

D. Excretion

B. Distribution

CYP enzyme inhibition is a pharmacokinetic interaction affecting:

A. Absorption

B. Distribution

C. Metabolism

D. Receptor activity

C. Metabolism

An additive pharmacodynamic interaction means:

A. 1 + 1 = 0

B. 1 + 1 = 3

C. 0 + 1 = 2

D. 1 + 1 = 2

D. 1 + 1 = 2

A synergistic interaction means:

A. 1 + 1 = 0

B. 1 + 1 = 2

C. 1 + 1 = 3

D. No effect occurs

C. 1 + 1 = 3

Potentiation is best represented by:

A. 1 + 1 = 2

B. 1 + 1 = 3

C. 0 + 1 = 2

D. 1 + 1 = 0

C. 0 + 1 = 2

Drug antagonism is best represented by:

A. 1 + 1 = 2

B. 1 + 1 = 3

C. 0 + 1 = 2

D. 1 + 1 = 0

D. 1 + 1 = 0

Which patient factor may alter drug response because of changes in renal function, liver function, and body composition?

A. Hair color

B. Age

C. Eye color

D. Hand dominance

B. Age

Malnutrition may increase free drug concentrations because it can cause:

A. Increased albumin

B. Increased metabolism

C. Decreased albumin

D. Increased excretion

C. Decreased albumin

In pharmacogenetics, a poor CYP2D6 metabolizer taking codeine is most likely to experience:

A. Increased efficacy

B. Reduced efficacy

C. Increased receptor affinity

D. Increased bioavailability

B. Reduced efficacy

A patient who is an ultra-rapid CYP2D6 metabolizer taking nortriptyline would most likely experience:

A. Elevated drug levels

B. Increased side effects

C. Lower drug levels and reduced response

D. Complete drug resistance

C. Lower drug levels and reduced response

Which is a major advantage of pharmacogenetic testing?

A. Eliminates all adverse effects

B. Guarantees drug efficacy

C. Helps optimize drug selection and dosing

D. Replaces clinical judgment

C. Helps optimize drug selection and dosing

Which factor is a significant barrier to widespread pharmacogenetic testing?

A. Excessive efficacy

B. Cost and limited provider knowledge

C. Improved outcomes

D. Better drug selection

B. Cost and limited provider knowledge