Pharmacokinetics

Question 1

Where are most drugs metabolised?

Answer 1

The liver

Question 2

What is the purpose of metabolism?

Answer 2

To increase water solubility and aid excretion

Question 3

What is the name given to the group of drugs that are activated follow metabolism?

Answer 3

Prodrugs

Question 4

Give 2 examples of prodrugs

Answer 4

Codeine

Enalapril

Question 5

What kind of metabolism can involve hydrolysis, oxidation or reduction?

Answer 5

Phase 1

Question 6

How does phase 1 metabolism provide an active site for phase 2?

Answer 6

Increasing the polarity

Question 7

Name the super family of metabolising enzymes?

Answer 7

Cytochrome P-450 enzymes

Question 8

What does the isoform of the cytochrome P-450 determine?

Answer 8

Drug specificity

Question 9

Name the three families of cytochrome P-450 that are important in oxidative drug metabolism

Answer 9

CYP1, CYP2, CYP3

Question 10

Name the major constitutive enzyme in the human liver

Answer 10

CYP3A4

Question 11

What can induce the enzyme CYP1A2?

Answer 11

Smoking

Question 12

What does increased water solubility mean in phase 2 metabolism?

Answer 12

Enhanced excretion of the metabolised compound

Question 13

What conjugation usually result in?

Answer 13

Inactivation

Question 14

What happens to the drug’s effect when the the drug metabolising enzyme is induced?

Answer 14

Decreased drug effect

Question 15

What are the most common enzyme inducers?

Answer 15

Alcohol and smoking

Question 16

What does increased synthesis lead to in terms of enzymes?

Answer 16

Increased activity

Question 17

What can drugs such as clarithromycin do?

Answer 17

Inhibit drug metabolising enzymes

Question 18

Lack/decreased activity of an enzyme often results in what?

Answer 18

Increased drug toxicity

Question 19

What can deficieny in renal function in young children lead to?

Answer 19

Metabolites rapidly building up to toxic levels

Question 20

By what ages can children metabolise many drugs more rapidly than adults?

Answer 20

Two

Question 21

Name the important process involved in eliminating drugs from the body?

Answer 21

Metabolism

Question 22

What is the therapeutic process?

Answer 22

Producing the correct therapeutic effect

Question 23

Name the four basic factors that determine drug pharmacokinetics?

Answer 23

Absorption
Distribution
Metabolism
Elimination

Question 24

What is Tmax?

Answer 24

Time to peak concentration

Question 25

What is Cmax?

Answer 25

The peak concentration

Question 26

What is the range of when the drug is active?

Answer 26

Therapeutic range

Question 27

What is the therapeutic index a measure of?

Answer 27

The range at which a drug is safe and active

Question 28

What bioavailability does a drug given intravenously have?

Answer 28

100%

Question 29

Most drugs are what kinds of acids?

Answer 29

Weak Acids

Question 30

Small changes in pH will do what to the ionisation of a drug?

Answer 30

Will significantly influence it

Question 31

Why should aspirin be absorbed more easily from the stomach?

Answer 31

It is a weak acid

Question 32

What must a drug be to pass across a lipid layer?

Answer 32

Must be in solution and be lipid soluble

Question 33

What is the name given to the ability of a drug to diffuse across a lipid barrier

Answer 33

Lipid-water partition coefficient

Question 34

Where does the bulk flow of liquid occur?

Answer 34

Through inter-cellular pores

Question 35

Why is bulk flow important?

Answer 35

It is the major mechanism which drugs cross through capillary walls

Question 36

What must drugs resemble to undergo active transport?

Answer 36

Naturally occurring compounds

Question 37

What is first pass metabolism?

Answer 37

Metabolism of drug prior to reaching systemic circulation

Question 38

What does subcutaneous route depend on?

Answer 38

Blood flow to site

Question 39

Drugs given via rectum bypass what?

Answer 39

First pass metabolism

Question 40

What do drugs generally need to reach to reach target tissues?

Answer 40

Systemic circulation

Question 41

How are most drugs given?

Answer 41

Orally

Question 42

Once a drug has been absorbed, what must it be ready for?

Answer 42

Biological action and distribution to tissues

Question 43

What, in theory, should volume of distribution be?

Answer 43

40L

Question 44

What does volume of distribution show?

Answer 44

Where drugs go

Question 45

How can side effects of a drug be cleared?

Answer 45

Metabolism or Renal excretion

Question 46

What is the name given to the theoretical volume of fluid from which a drug is completely removed over a period of time?

Answer 46

Clearance

Question 47

What is the name given to the time taken for the drug concentration in the blood to decline to half of the current value?

Answer 47

Half-life

Question 48

What does a long half-life indicate?

Answer 48

Plasma levels will stay long for higher

Question 49

What will the knowledge of the half-life of a drug help us to work out?

Answer 49

How often a drug needs to be administered

Question 50

What will increase the toxicity of a drug in terms of half-life?

Answer 50

Prolongation of the half life

Question 51

Why do most drugs need to be given chronically?

Answer 51

To have a therapeutic effect

Question 52

How many half-lives does it take to reach stable plasma levels?

Answer 52

5-6

Question 53

What are the primary organs for drug excretion?

Answer 53

The kidneys

Question 54

What is the main mechanism used for drug excretion?

Answer 54

Glomerular filtration

Question 55

If a patient is dehydrated, what happens to the clearance of a drug?

Answer 55

It reduces

Question 56

How much bile a day does the liver secrete?

Answer 56

1 litre

Question 57

What determines where a drug will reach?

Answer 57

Chemical properties of the drug

Question 58

What is the definition of drug interaction?

Answer 58

Modification of a drug's effect by prior or administration of a drug at the same time

Question 59

What does a narrow therapeutic index indicate?

Answer 59

A small change in blood levels can induce profound toxicity from a drug

Question 60

What can increase the probability of a drug-drug interaction?

Answer 60

Increase of number of medicaments

Question 61

What spectrum of antibiotics can destory normal gut flora?

Answer 61

Broad Spectrum

Question 62

Where are most oral medicines absorbed?

Answer 62

The small intestine

Question 63

Following absorption, where are drugs distributed to?

Answer 63

The site of action

Question 64

Name the main inducer of cytochrome P450 enzymes?

Answer 64

Smoking

Question 65

Why can drugs that work on the brain not be taken alongside alcohol?

Answer 65

As they can produce a synergistic effect that leads to toxicity

Question 66

Where does elimination of drugs occur?

Answer 66

In the kidney

Question 67

What side effect does isionazid produce?

Answer 67

Peripheral neuropathy

Question 68

What is the definition of first pass metabolism?

Answer 68

When drug is metabolised before reaching systemic circulation

Question 69

What are the examples of sub-acute onset of adverse drug reactions?

Answer 69

Rash | Serum Sickness

Question 70

How long does the onset of a latent adverse drug reaction?

Answer 70

Over 2 days

Question 71

Which type of adverse drug reaction does not require a change of therapy?

Answer 71

Acute

Question 72

What are type A adverse drug reactions linked to>

Answer 72

Too high a dose

Question 73

How are type A adverse drug reactions stopped?

Answer 73

When drug is reduced or stopped

Question 74

Chronic adverse drug reactions are related to what?

Answer 74

Duration of treatment

Question 75

Give an example of an ADR that cannot be avoided

Answer 75

Nausea in chemotherapy treatment