Quantitative Pharmacodynamics

Question 1

What is Pharmacodynamics ?

Answer 1

A study of what the drug does to the body

Question 2

What is meany by Potency ?

Answer 2

The concentration of a drug needed to have a certain percentage effect

Question 3

What is meant by Efficacy ?

Answer 3

The maximum response achievable (this can differ)

Question 4

What is meant by Fractional Occupancy (f) ?

Answer 4

The fraction of total receptor that is bind w/Ligand

Question 5

What is meant by the Kd of a drug ?

Answer 5

The concentration of ligand that results in half of receptors being occupied

Question 6

What does a small Kd value tell you ?

Answer 6

• That the dug has a high affinity = easier for ligand to occupy receptor

Question 7

What does a large Kd value tell you ?

Answer 7

• Drug has a low affinity = not easy for ligand to bind to receptor

Question 8

Free energy is released upon ligand binding to receptor. TRUE or FALSE ?

Answer 8

TRUE

Question 9

High affinity binding occurs when large amount of free energy is released upon ligand binding. TRUE or FALSE ?

Answer 9

TRUE

Question 10

Total binding = specific binding + non-specific binding. TRUE or FALSE ?

Answer 10

TRUE

Question 11

How is Kd measured ?

Answer 11

1) The ligand is labelled using a Radionuclide e.g: 3H.

2) Binding is then measured

Question 12

What is meant biological effect ?

Answer 12

The response of a tissue to a drug

Question 13

What is meant by EC50 ?

Answer 13

The concentration of a drug required to cause half the maximum effect

Question 14

What is the role of a Partial Agonist ?

Answer 14

Fully occupies the receptor without activating the maximum response

Question 15

What is meant by a Spare receptor ?

Answer 15

When an Agonist produces a max response without all the receptors being occupied

Spare receptor is also known as ‘Receptor reserve’

Question 16

Beta blockers are often Beta adrenoceptor antagonists; e.g: Propanolol. TRUE or FALSE ?

Answer 16

TRUE

Question 17

Pindolol and Rimonabant are exceptions beta blockers that act as Beta adrenoceptor antagonists. TRUE or FALSE ?

Answer 17

TRUE.
Pindolol act as a partial agonist
Rimonabant acts as an Inverse agonist

Question 18

Isoprenaline is a full agonist that activates beta adrenergic receptors. TRUE or FALSE ?

Answer 18

TRUE

Question 19

Prenalterol is a partial agonist that activates beta adrenergic receptors. TRUE or FALSE ?

Answer 19

TRUE

Question 20

Properties of Agonists and Antagonists ?

Answer 20

• Reversible
• Non -covalent
• Competitive
• Specific and selective

Question 21

What is an Irreversible Antagonist ?

Answer 21

An Antagonist binds to the same site as the agonist.

It does not dissociate – it binds covalently. e.g; Omeprazole

Question 22

The effect of the competitive antagonist can be overcome with a higher concentration of agonist. TRUE or FALSE ?

Answer 22

TRUE

Question 23

What is an Allosteric/Non-competitive Antagonist ?

Answer 23

Antagonist binds to a different site on the receptor, induces a conformational change therefore receptor cannot be activated by agonist

Question 24

What is an Inverse agonist ?

Answer 24

Agonist that reduces the amount of receptor available to spontaneously activate itself.

It also reduces the resting response of a tissue.