Module 3 - Pharmacokinetics and Pharmacodynamics

Question 1

What is pharmacodynamics?

Answer 1

What a drug does to the body

Question 2

What is involved in pharmacodynamics?

Answer 2

The effect of the drug, mechanism and their action

Question 3

What is drug selectivity?

Answer 3

The number of molecular targets the drug interacts with

Question 4

What is drug specificity?

Answer 4

The number of effects the drug produces

Question 5

What is drug affinity

Answer 5

Affinity = affection
Tendency of a drug to combine with receptor site

Question 6

What is an adverse reaction?

Answer 6

A biological effect that is not intended

Question 7

What are the four main types of molecular drug targets?

Answer 7

Transporter
Enzyme
Ion channel
Receptor

Question 8

What is meant by receptor agonist?

Answer 8

A drug/substance that binds to a receptor and causes the SAME effect

Question 9

What is a partial agonist?

Answer 9

Unable to produce an active response even when all receptors are occupied?

Question 10

What is an orthosteric site?

Answer 10

An active site

Question 11

What is an allosteric site?

Answer 11

Binds to a different site and causes a reaction

Question 12

What is a receptor antagonist?

Answer 12

Binds to a receptor target but DOES NOT elicit a response

Question 13

What effect does a receptor agonist produce?

Answer 13

Prevents binding of agonist to receptor thus preventing activation of receptor

Question 14

What are the three (3) types of receptor antagonists?

Answer 14

Reversible, irreversible and non-competitive

Question 15

What does a reversible receptor antagonist do?

Answer 15

Interferes with binding of endogenous agonist to orthosteric (active) site

Question 16

What does a irreversible receptor antagonist do?

Answer 16

Causes target receptor to become permanently unavailable for binding of agonist

Question 17

What does a non-competitive receptor antagonist do?

Answer 17

Blocks response to agonist

Question 18

What do allosteric modulators do?

Answer 18

Indirectly alters function of a receptor in positive or negative way

Question 19

How do allosteric modulators produce a pharmacological response?

Answer 19

Activating receptor to cause different biological response
Alter binding affinity
Changing the efficacy of receptor

Question 20

What is potency?

Answer 20

How much drug is required to produce an effect

Question 21

What is EC50?

Answer 21

The drug concentration as which a drug produces 50% of the maximal response

Question 22

What is efficacy?

Answer 22

Measure of how big an effect the drug will have when all targets are occupied

Question 23

What are the two types of transporters?

Answer 23

Facilitated and active

Question 24

When must transporters be utilised?

Answer 24

When a drug is not soluble and cannot passively diffuse across a membrane

Question 25

What are ion channels?

Answer 25

Transmembrane proteins that control ion flow across a cell membrane

Question 26

What are the main ion channels?

Answer 26

Voltage gated ion channels and intracellular ligand gated ion channels

Question 27

What are enzymes?

Answer 27

Catalysts that speed up rate of all chemical reactions that take place with cells

Question 28

What are receptors?

Answer 28

Signalling proteins that recognise and response to chemical messengers to change a function within a cell

Question 29

What are the four (4) families of receptors?

Answer 29

1. Ligand gated ion channels 2. G-coupled protein receptors 3. Kinase receptors 4. Nuclear receptors

Question 30

How do ligand gated channels work?

Answer 30

A drug binds to a particular site on the transmembrane protein to open up the gate and allow ions to flow through

Question 31

How do G-coupled protein receptors work?

Answer 31

A ligand will bind to outside of a G-coupled protein receptor. Receptor undergoes conformational change that allows it to interact with G-protein that will pass signal on to other intermediates in signalling pathway

Question 32

What is pharmacokinetics?

Answer 32

What the BODY does to the drug

Question 33

What is involved in pharmacokinetics

Answer 33

1. Concentration of a drug increases as it is absorbed in the body 2. Hits peak concentration 3. Process of elimination occurs (drug concentration in the plasma reduces)

Question 34

What is the importance of understanding a drugs pharmacokinetic profile?

Answer 34

Allows use to decide appropriate dosages, determine dosing regimes, interpret drug reactions and adjust doses according to response

Question 35

What are the two main categories of drug administration?

Answer 35

Systemic administration and target administration

Question 36

What occurs during systemic administration?

Answer 36

Drug enters circulation and is carried to site of action (needs to be able to cross biological membranes)

Question 37

What occurs during target administration?

Answer 37

Drug is delivered to the site of action (proximity delivered to tissue/organ where desired effect is intended)

Question 38

What is the difference between lipid soluble drugs and ionised/charged drugs?

Answer 38

Lipid soluble drugs readily pass through lipid membrane, ionised/charged drugs have difficulty crossing cell membranes

Question 39

What are the four (4) main ways a drug can cross cell membranes?

Answer 39

Passive diffusion Facilitated transport Active transport Aquaporin

Question 40

What is lipophilicity?

Answer 40

Passes through cell membrane more easily (easier absorption)

Question 41

What is hydrophilicity?

Answer 41

Difficulty crossing lipid bilayer

Question 42

What is the impact of ionisation on drug absorption?

Answer 42

Un-ionised drugs (lipid soluble) easily diffuse across lipid membrane compared to ionised drugs

Question 43

What are the main physiological barriers of drug absorption?

Answer 43

Nature of the tissue Channel and transporter Surface area (large surface area increases absorption) Blood flow (increased blood supply results in increased absorption)

Question 44

What factors mainly impact distribution?

Answer 44

Physiochemical properties of a drug (e.g. size/molecular weight, lipophilicity/hydrophilicity, ionisation and tissue binding) Physiology of the person (e.g. circulation, permeability of membranes, tissue mass and channel/transporter)

Question 45

What is the impact of a hydrophilic drug on distribution?

Answer 45

A large portion will remain in the extracellular fluid compartment as it cannot cross cell membranes

Question 46

What is the impact of a Lipophilic drug on distribution?

Answer 46

Can move between intracellular and intravascular compartments