pharmacology- claire

Question 1

Which of the following statements about first-order kinetics is TRUE?
A. The rate of elimination is constant regardless of drug concentration
B. The drug is eliminated in a linear fashion
C. Half-life increases as drug concentration increases
D. Elimination rate is proportional to plasma drug concentration
E. Drug clearance is saturated at therapeutic levels

Answer 1

D. Elimination rate is proportional to plasma drug concentration

Question 2

How many half-lives does it typically take to reach steady-state drug concentration?
A. 2
B. 3
C. 4–5
D. 6–7
E. 10

Answer 2

C. 4–5

Question 3

What is the correct formula for bioavailability (F)?
A. F = (Rate of elimination) / (Plasma concentration)
B. F = (Total drug absorbed) / (Drug clearance)
C. F = (Vd × Plasma concentration) / Dose
D. F = (Amount of drug in plasma) / (Total amount administered)
E. F = (Clearance × half-life) / Volume of distribution

Answer 3

D. F = (Amount of drug in plasma) / (Total amount administered)

Question 4

A high volume of distribution (Vd) suggests that the drug:
A. Remains mostly in the plasma
B. Is hydrophilic
C. Is extensively distributed into tissues
D. Has low lipid solubility
E. Has poor membrane permeability

Answer 4

C. Is extensively distributed into tissues

Question 5

Which of the following routes of administration avoids first-pass metabolism?
A. Oral
B. Sublingual
C. Rectal (upper)
D. Nasogastric
E. Enteral

Answer 5

B. Sublingual

Question 6

Which of the following is NOT a parenteral route of administration?
A. Intramuscular
B. Subcutaneous
C. Oral
D. Intravenous
E. Intradermal

Answer 6

C. Oral

Question 7

Which of the following mechanisms is energy-independent?
A. Active transport
B. Secondary active transport
C. Facilitated diffusion
D. Pinocytosis
E. Passive diffusion

Answer 7

E. Passive diffusion

Question 8

What process is NOT involved in the absorption of oral drugs?
A. Disintegration
B. Dissolution
C. Diffusion
D. Filtration
E. Passive diffusion

Answer 8

D. Filtration

Question 9

What law governs passive diffusion across membranes?
A. Boyle’s law
B. Fick’s law
C. Dalton’s law
D. Michaelis-Menten kinetics
E. Henderson-Hasselbalch equation

Answer 9

B. Fick’s law

Question 10

Which factor has the GREATEST effect on the distribution rate of a drug?
A. Food in the stomach
B. Organ perfusion rates
C. GI motility
D. Stomach pH
E. Formulation of the drug

Answer 10

B. Organ perfusion rates

Question 11

Which of the following is true of tissue binding of drugs?
A. Increases clearance
B. Has no effect on elimination
C. Shortens half-life
D. Increases apparent volume of distribution
E. Prevents the drug from acting

Answer 11

D. Increases apparent volume of distribution

Question 12

What does selectivity in drug-receptor interaction refer to?
A. Strength of drug binding
B. Drug’s ability to bind all receptors equally
C. Degree to which a drug acts on a specific receptor over others
D. Number of second messengers activated
E. Ability to cross membranes

Answer 12

C. Degree to which a drug acts on a specific receptor over others

Question 13

What is the definition of a ligand?
A. A molecule that blocks a receptor
B. A drug that enhances an enzyme’s function
C. A substance that binds specifically to a receptor site
D. A molecule that activates only ion channels
E. A protein embedded in a membrane

Answer 13

C. A substance that binds specifically to a receptor site

Question 14

What is the primary second messenger system activated by some GPCRs?
A. Tyrosine kinase
B. Voltage-gated calcium channels
C. JAK/STAT pathway
D. Adenylyl cyclase/cAMP
E. Guanyl cyclase

Answer 14

D. Adenylyl cyclase/cAMP

Question 15

Which receptor type directly influences gene transcription?
A. GPCR
B. Voltage-gated ion channel
C. Enzyme-linked receptor
D. Intracellular receptor
E. Ligand-gated ion channel

Answer 15

D. Intracellular receptor

Question 16

What does the Kd of a drug represent?
A. The maximum effect produced by a drug
B. The plasma concentration at which 50% of receptors are occupied
C. The dose that kills 50% of the population
D. The bioavailability of the drug
E. The time taken to reach steady state

Answer 16

B. The plasma concentration at which 50% of receptors are occupied

Question 17

Which of the following statements best describes potency?
A. It reflects how long a drug stays in the body
B. It refers to the drug’s selectivity
C. It is the maximum effect achievable
D. It is the amount of drug required to produce a specific effect
E. It is the rate of elimination

Answer 17

D. It is the amount of drug required to produce a specific effect

Question 18

What is a characteristic of a competitive antagonist?
A. Produces maximal response without binding
B. Binds irreversibly to the receptor
C. Competes with the agonist at the same binding site
D. Activates the receptor partially
E. Enhances the agonist’s response

Answer 18

C. Competes with the agonist at the same binding site

Question 19

What does drug efficacy refer to?
A. How tightly the drug binds to its receptor
B. Dose needed to produce a minimal effect
C. Maximum pharmacological response achievable
D. Number of receptor subtypes affected
E. Area under the curve (AUC) of plasma concentration

Answer 19

C. Maximum pharmacological response achievable

Question 20

Which of the following best defines drug clearance (CL)?
A. The amount of drug excreted in urine
B. Volume of plasma from which the drug is removed per unit time
C. The half-life of the drug
D. The total drug eliminated from the body
E. The speed of drug metabolism in the liver only

Answer 20

B. Volume of plasma from which the drug is removed per unit time

Question 21

What does a high plasma protein binding of a drug suggest?
A. Faster renal clearance
B. Less drug available for distribution
C. Increased drug absorption
D. Enhanced drug metabolism
E. Shorter half-life

Answer 21

B. Less drug available for distribution

Question 22

Which of the following best describes the JAK-STAT pathway?
A. Ion channel opening causing depolarization
B. GPCR activating adenylyl cyclase
C. Cytokine receptor activating transcription via kinase binding
D. Ligand-gated ion channel causing calcium influx
E. Steroid binding to nuclear DNA

Answer 22

C. Cytokine receptor activating transcription via kinase binding

Question 23

Which statement about zero-order kinetics is TRUE?
A. A constant fraction is eliminated per unit time
B. Elimination is dose-independent
C. Drug is eliminated in proportion to its concentration
D. Elimination rate is constant regardless of concentration
E. Half-life remains constant

Answer 23

D. Elimination rate is constant regardless of concentration

Question 24

Which type of diffusion requires carrier proteins but no energy input?
A. Active transport
B. Passive diffusion
C. Facilitated diffusion
D. Pinocytosis
E. Endocytosis

Answer 24

C. Facilitated diffusion

Question 25

A drug is 80% protein-bound. What is true about the unbound fraction? A. It cannot enter tissues B. It has no pharmacological effect C. It is responsible for drug action D. It is more likely to be stored in fat E. It cannot be filtered by the kidney

Answer 25

C. It is responsible for drug action

Question 26

Which of the following is an example of an enteral route of administration? A. Intramuscular injection B. Inhalation C. Sublingual tablet D. Oral capsule E. Intravenous infusion

Answer 26

D. Oral capsule

Question 27

What is meant by the ‘threshold’ in a dose-response curve? A. Maximum tolerated dose B. Dose at which drug toxicity begins C. Dose below which no effect is seen D. Dose at which all receptors are saturated E. Dose at which drug elimination starts

Answer 27

C. Dose below which no effect is seen

Question 28

What is the typical outcome of tissue binding of a drug? A. Faster elimination B. Decreased bioavailability C. Prolonged duration of action D. Increased first-pass metabolism E. Increased protein binding in plasma

Answer 28

C. Prolonged duration of action

Question 29

Which of the following is a feature of an intrinsic enzyme-linked receptor? A. Direct G-protein activation B. Ion conductance control C. Built-in catalytic domain D. Ligand-independent activation E. Exclusively found in neurons

Answer 29

C. Built-in catalytic domain

Question 30

Which of the following best defines the Volume of Distribution (Vd)? A. Volume of blood cleared of drug per minute B. Plasma volume only C. Theoretical volume drug would occupy if evenly distributed D. Volume of interstitial fluid in body E. Total amount of plasma proteins in body

Answer 30

C. Theoretical volume drug would occupy if evenly distributed

Question 31

A drug with high lipophilicity, low plasma protein binding, and large tissue binding is likely to have which of the following characteristics? A. Low volume of distribution and short half-life B. High volume of distribution and prolonged half-life C. High plasma concentration and rapid clearance D. Minimal accumulation in tissues E. Fast onset and short duration of action

Answer 31

B. High volume of distribution and prolonged half-life

Question 32

If a drug follows first-order kinetics and has a half-life of 6 hours, what percentage of the drug remains after 18 hours? A. 75% B. 12.5% C. 25% D. 6.25% E. 50%

Answer 32

B. 12.5%

Question 33

A patient receives a loading dose of a drug with a high volume of distribution. What is the primary purpose of this loading dose? A. To reduce adverse effects B. To overcome protein binding C. To rapidly achieve therapeutic plasma concentration D. To bypass hepatic metabolism E. To maintain steady-state levels

Answer 33

C. To rapidly achieve therapeutic plasma concentration

Question 34

Which of the following best explains why repeated dosing of a drug with a short half-life can still lead to accumulation? A. The drug induces its own metabolism B. Elimination is saturable C. Doses are given before complete elimination D. Distribution is confined to plasma E. Renal clearance increases over time

Answer 34

C. Doses are given before complete elimination

Question 35

Which statement is true regarding bioavailability and the first-pass effect? A. Intravenous administration has the lowest bioavailability B. Rectal administration always avoids first-pass metabolism C. Bioavailability is unaffected by gut wall metabolism D. First-pass metabolism reduces the bioavailability of orally administered drugs E. Drugs with low solubility tend to have 100% bioavailability

Answer 35

D. First-pass metabolism reduces the bioavailability of orally administered drugs

Question 36

In a dose-response experiment, a competitive antagonist is added. What would you expect to see on a graded dose-response curve? A. Curve shifts left; reduced efficacy B. Curve shifts right; same efficacy C. Curve shifts down; increased potency D. No change in the curve E. Curve shifts left; increased EC50

Answer 36

B. Curve shifts right; same efficacy

Question 37

Which of the following would most likely increase the steady-state plasma concentration of a drug? A. Increasing clearance B. Decreasing dosing frequency C. Increasing volume of distribution D. Decreasing clearance E. Enhancing first-pass metabolism

Answer 37

D. Decreasing clearance

Question 38

Which receptor type is correctly paired with its second messenger system? A. GPCR – JAK/STAT B. Ligand-gated ion channel – IP3/DAG C. Intracellular receptor – cAMP D. GPCR – Adenylyl cyclase/cAMP E. Enzyme-linked receptor – Voltage-gated ion channel

Answer 38

D. GPCR – Adenylyl cyclase/cAMP

Question 39

A drug has a high affinity but low efficacy. What is the most likely classification of this drug? A. Full agonist B. Non-competitive antagonist C. Inverse agonist D. Partial agonist E. Competitive antagonist

Answer 39

D. Partial agonist

Question 40

In the context of facilitated diffusion across membranes, which of the following is FALSE? A. It is saturable B. It uses a concentration gradient C. It requires a transporter protein D. It consumes ATP E. It shows specificity for substrates

Answer 40

D. It consumes ATP