Lecture 2: Drug/ Target Interactions

Question 1

What are the drug characteristics that affect absorption? (4)

Answer 1

Molecular weight, ionisation, solubility and formulation

Question 2

What patient factors affect absorption?

Answer 2

• Route of administration
• Contents of GI tract

Question 3

Do drugs bound to plasma proteins cross the membrane?

Answer 3

No

Question 4

How does malnutrition lead to an increase in free drug?

Answer 4

Malnutrition means a decrease in albumin so an increase in free drug.

Question 5

Where do lipophilic drugs accumulate?

Answer 5

Adipose tissue

Question 6

How much of digoxin is absorbed?

Answer 6

70-80%

Question 7

What is the half life of digoxin?

Answer 7

26-45 hours

Question 8

What is the primary route of metabolism?

Answer 8

Liver

Question 9

What can statins interact with? (4)

Answer 9

• Grapefruit
• Warfarin
• Courmarins
• Certain antimycotics

Question 10

How do you calculate the therapeutic index?

Answer 10

minimum toxic dose/ minimum effective dose

Question 11

What drugs are renally cleared? (8)

Answer 11

• Aminoglycosides
• Glycopeptides
• Amikacin
• Gentaminic
• Vancomycin
• Digoxin
• Lithium
• morphine 6-glucuronide

Question 12

What is steady state?

Answer 12

Drug administered is equal to the amount of drug eliminated within one dosing interval resulting in a plateau or contant serum drug level

Question 13

How many half lifes does it take to reach 100% steady state?

Answer 13

5

Question 14

What is efficacy?

Answer 14

The degree to which a drug is able to produce the desires response

Question 15

What is the effective concentration 50% ?

Answer 15

Concentration of the drug which induces a specified clinical effect in 50% of subjects

Question 16

What is the lethal dose 50%

Answer 16

Concentration of the drug which induces death in 50% of subjects

Question 17

What is the theraputic index?

Answer 17

Measure of the safety of the drug

Question 18

What is the margin of safety?

Answer 18

Margin between the theraputic and lethal doses

Question 19

What is an agonist?

Answer 19

A ligand that binds and actiavtes a receptor

Question 20

Give examples of endogenous ligands?

Answer 20

• Neaurotransmitters
• Hormones

Question 21

How long do ion channel linked receptors take to exert an effect?

Answer 21

Milliseconds

Question 22

How long do G-protien linked receptors take to exert an effect?

Answer 22

Seconds

Question 23

How long do tyrosine kinase linked linked receptors take to exert an effect?

Answer 23

Minutes

Question 24

How long do DNA linked receptors take to exert an effect?

Answer 24

Hours to days

Question 25

Give an example of an ion channel linked receptor?

Answer 25

Nicotinic acetylecholine receptor

Question 26

Give an example of a G-protien linked receptor?

Answer 26

B-adrenergic receptor

Question 27

Give an example of a tyrosine kinase linked receptor?

Answer 27

Insulin receptor

Question 28

Give an example of an DNA linked linked receptor?

Answer 28

Steroid receptor

Question 29

Where are cell surface receptors found?

Answer 29

- Cell surface - On an organelle within the cell - In the cytoplasm

Question 30

What can cell surface receptors be?

Answer 30

Proteins or glucoprotiens

Question 31

What actions can occur when a drug binds to its receptor?

Answer 31

- Ions channel opens and closes - Second messenger is activated: cAMP, Calcium, inositol phosphates etc. This initiates a series of chemical reactions - Cellular function can be turned on/ off

Question 32

What is the treatment for cardiovascular disease?

Answer 32

Manipulation of cardiac output, peripheral vascular resistance and blood volume

Question 33

What is the prevention for cardiovascular disease?

Answer 33

- Reduce platelet adhesion - Reduce cholesterol

Question 34

How do you reduce atherogenesis?

Answer 34

Reduce platelet adhesion

Question 35

What is used to reduce platelet adhesion?

Answer 35

- Irreversible cyclooxygenase inhibitors: aspirin - Adenosine diphosphate receptor inhibitor: clopidogrel

Question 36

What drugs cause contraction?

Answer 36

- calcium channel blocker - Agonst - Noradraline - Histamine - angiotensin

Question 37

What drugs cause relaxation?

Answer 37

- Potassium channel activators - Adenosine - B agonist - Prostaglandins

Question 38

What causes cell relaxation?

Answer 38

- Noradrenaline - Histamine - Angiotensin

Question 39

What agonists cause cell relaxation and hyperpolarisation?

Answer 39

- Adenosine - B agonists - Prostaglandins - PDE Inhibitor