Pharmacodynamics MCQs

MCQs & Solution

Q1. Pharmacodynamics involves the following?

a) Information about main mechanisms of drug absorption

b) Information about unwanted effects

c) Information about biological barriers

d) Information about excretion of a drug from the organism

Ans: b) Information about unwanted effects

Q2. What does “affinity” mean?

a) A measure of how tightly a drug binds to plasma proteins

b) A measure of how tightly a drug binds to a receptor

c) A measure of inhibiting potency of a drug

d) A measure of bioavailability of a drug

Ans: b) A measure of how tightly a drug binds to a receptor

 Q3. Target proteins which a drug molecule binds are:

a) Only receptors

b) Only ion channels

c) Only carriers

d) All of the above

ANS: d) All of the above

 Q4. Which has no intrinsic activity ?

a) Agonist

b) Antagonist

c) Partial Agonist

d) Inverse agonist

Ans: b) Antagonist

Q5. The characteristic feature of compititive antagonist is a substance Except:

a) Interacts with the receptor without producing any effect

b) Decrease the potency of agonist

c) Decrease the efficacy of agonist

d) Increase the loading dose of an exogenous agonist to produce therapeutic effect.

 Ans: c) Decrease the efficacy of agonist

Q6. A non competitive inhibitor:

a) Decrease the efficacy of agonist/substrate

b) Decrease the potency of agonist

c) Increase the efficacy of agonist/substrate

b) Increase the potency of agonist/substrate

 Ans: a) Decrease the  efficacy of agonist/substrate

Q7. Pick out the example of non-competitive inhibition:

a) ChE —– Physostigmine

b) Xanthine oxidase——–Allopurinol

c) COX——Aspirin

d) Folate Synthatase—-Sulfonamide

 Ans: c) COX——Aspirin

Q8. Presynaptic nerve ending contains:

a) L type Ca2+ channel

b) N type Ca2+ channel

c) Both

d) None

 Ans: b) N type Ca2+ channel

9 Which is NOT a second messenger of the G-protein-coupled (metabotropic) receptor:

a) PIP2

b) IP3

c) DAG

d) cAMP

 Ans: a) PIP2

Ligands/Drugs- 1st messenger

G-Proteins- Signal Transducer

IP3/DAG & cAMP- 2nd messenger

Ca2+- 3rd messenger

Q10. Tick the substance which changes the activity of an effector element but doesn’t belong to messengers:

a) cAMP

b) cGMP

c) G–protein

d) Calcium ions

Ans: c) G–protein

Q11. Which is NOT a ligand gated ion channel.

a) 5HT-3 R

b) NMDA R

c) GABAB R

d) Glycene R

 Ans: c) GABAB R

Q12. All of the following statements about efficacy and potency are true EXCEPT:

a) Efficacy is usually a more important clinical consideration than potency

b) Efficacy is the maximum effect of a drug

c) Potency is a comparative measure, refers to the different doses of two drugs that are needed to produce the same effect

d) The ED50 is a measure of drug’s efficacy

 Ans: d) The ED50 is a measure of drug’s efficacy

Q13. Which effect may lead to toxic reactions when a drug is taken continuously or repeatedly?

a) Refractoriness

b) Cumulative effect

c) Tolerance

d) Tachyphylaxis

 Ans: b) Cumulative effect

Q14. What phenomenon can occur in case of using a combination of drugs?

a) Tolerance

b) Tachyphylaxis

c) Accumulation

d) Synergism

 Ans: d) Synergism

Q15. If two drugs with the same effect, taken together, produce an effect that is equal in magnitude to the sum of the effects of the drugs given individually, it is called as:

a) Antagonism

b) Potentiation

c) Additive effect

d) None of the above

 Ans: c) Additive effect

Q16. Therapeutic index (TI) is:

a) A ratio used to evaluate the safety and usefulness of a drug for indication

b) A ratio used to evaluate the effectiveness of a drug

c) A ratio used to evaluate the bioavailability of a drug

d) A ratio used to evaluate the elimination of a drug

 Ans: a) A ratio used to evaluate the safety and usefulness of a drug for indication

TI = LD50/ED50

Q17. Which is NOT responsible for Smooth muscle contraction

a) Activation of Ca2+-Calmodulin

b) Activation of Rho Kinase

c) Activation of Adenylyl cyclase

d) Activation of Phospholypase-C

 Ans: c) Activation of Adenylyl cyclase

Q18. Which is not regulate Ca2+ ion within the cell

a) Gs protein

b) Rynodine (RyR) receptor

c) IP3 Receptor

d) Glycene receptor

Ans: d) Glycene receptor

Q19. Which receptor act via GqPCR

a) 5HT2 R

b) H2R

c) M2 R

d) β R

 Ans: a) 5HT2 R

5HT1-GiPCR

5HT2-GqPCR

5HT4-GsPCR

Q20. Auto phosphorylation occurs in which drug bind with its Enz-linked receptor:

a) Growth hormone

b) Cytokines

c) Insulin

d) Interferon

Ans: c) Insulin

Q21. Target proteins which a drug molecule binds are:

a) Only receptors
b) Only ion channels
c) Only carriers
d) All of the above

Ans: d) All of the above

Q22. An antagonist is a substance that:

a) Binds to the receptors and initiates changes in cell function, producing maximal effect
b) Binds to the receptors and initiates changes in cell function, producing submaximal effect
c) Interacts with plasma proteins and doesn’t produce any effect
d) Binds to the receptors without directly altering their functions

Ans: d) Binds to the receptors without directly altering their functions

Q23. The substance binding to one receptor subtype as an agonist and to another as an antagonist is called:

a) Competitive antagonist
b) Irreversible antagonist
c) Agonist-antagonist
d) Partial agonist

Ans: c) Agonist-antagonist

Q24. Irreversible interaction of an antagonist with a receptor is due to:

a) Ionic bonds
b) Hydrogen bonds
c) Covalent bonds
d) All of the above

 Ans: c) Covalent bonds
Q25. The increase of second messengers’ (cAMP, cGMP, Ca2+ etc.) concentration leads to:

a) Inhibition of intracellular protein kinases and protein phosphorylation
b) Proteinkinases activation and protein phosphorylation
c) Blocking of interaction between a receptor and an effector
d) Antagonism with endogenous ligands

 Ans: b) Proteinkinases activation and protein phosphorylation
Q26. All of the following statements about efficacy and potency are true EXCEPT:

a) Efficacy is usually a more important clinical consideration than potency
b) Efficacy is the maximum effect of a drug
c) Potency is a comparative measure, refers to the different doses of two drugs that are needed to produce the same effect
d) The ED50 is a measure of drug’s efficacy

Ans: d) The ED50 is a measure of drug’s efficacy

Q27. Give the definition for a therapeutical dose:

a) The amount of a substance to produce the minimal biological effect
b) The amount of a substance to produce effects hazardous for an organism
c) The amount of a substance to produce the required effect in most patients
d) The amount of a substance to accelerate an increase of concentration of medicine in an organism

Ans: c) The amount of a substance to produce the required effect in most patients

Q28. Therapeutic index (TI) is:

a) A ratio used to evaluate the safety and usefulness of a drug for indication
b) A ratio used to evaluate the effectiveness of a drug
c) A ratio used to evaluate the bioavailability of a drug
d) A ratio used to evaluate the elimination of a drug

 Ans: a) A ratio used to evaluate the safety and usefulness of a drug for indication
 Q29. Tick the substances whose mechanisms are based on interaction with ion channels

a) Sodium channel blockers
b) Calcium channel blockers
c) Potassium channels activators
d) All of the above

Ans: d) All of the above

 Q30. The substance binding to one receptor subtype as an agonist and to another as an antagonist is called:

a) Competitive antagonist
b) Irreversible antagonist
c) Agonist-antagonist
d) Partial agonist

 Ans: c) Agonist-antagonist