M104 T2 L14

Question 1

What are the six rights of prescribing?

Answer 1

Right patient
Right drug
Right route
Right dose
Right time
Right outcome

Question 2

What is Pharmacokinetics about as a medical student?

Answer 2

it’s about relating its principles to clinical applications

Question 3

What does having a knowledge of Pharmacodynamics help with?

Answer 3

the safe and effective use of medicines
working out the optimal dosage regimen
predicting potential drug interactions

Question 4

How is the optimal dosage regimen worked out?

Answer 4

dose, route
dose interval
duration of treatment

Question 5

What are the four subheadings of Pharmacokinetics? (ADME)

Answer 5

Absorption
Distribution
Metabolism
Excretion

Question 6

Where does absorption of a drug take place normally?

Answer 6

a receptor site

Question 7

What are the two types of routes for drug administration?

Answer 7

Enteral and Parenteral

Question 8

What are the two routes of enteral drug administration?

Answer 8

Oral

Rectal

Question 9

What are the two routes of parenteral drug administration?

Answer 9

Sublingual

Buccal

Question 10

What happens to drugs administered buccally?

Answer 10

they are held or applied in the buccal area
they diffuse through the oral mucosa
they then enter directly into the bloodstream

Question 11

What happens to drugs administered sublingually?

Answer 11

the drug is held under the tongue to dissolve

it is absorbed into the blood through the mucal membrane tissue there

Question 12

What factors influence enteral absorption?

Answer 12

GI motility
Absorptive area
GI blood flow
Drug properties
Drug physicochemical properties
Drug binding

Question 13

How does rapid GI motility influence enteral absorption?

Answer 13

rapid GI motility means that there’s not enough time for the drug to maintain contact with the GI system
AAR it is not properly absorbed (fully)

Question 14

How does inflammation influence enteral absorption?

Answer 14

it lowers the absorptive area available for the drug

Question 15

How does GI blood flow influence enteral absorption?

Answer 15

lack of / suboptimal blood flow results in lowered absorption rates

Question 16

What are two properties of drugs being absorbed?

Answer 16

particle size and formulation

Question 17

How does drug binding influence enteral absorption?

Answer 17

the drug needs to be able to bind to cells in the GI system if it is going to be absorbed

Question 18

What are examples of drug physicochemical properties that influence enteral absorption?

Answer 18

solubility

pH

Question 19

How does solubility of drugs influence enteral absorption?

Answer 19

more lipid soluble, increased absorption

less more water soluble, decreased absorption

Question 20

How does drug pH influence enteral absorption?

Answer 20

acidic drugs are better absorbed in acidic media

basic drugs are better absorbed in basic media

Question 21

What types of molecules are not lipid soluble?

Answer 21

hydrophilic, polar or ionized mlcs, e.g. Na+, K+

Question 22

What types of molecules are water soluble?

Answer 22

hydrophilic, polar or ionized mlcs, e.g. Na+, K+

Question 23

Where are acidic drugs better absorbed?

Answer 23

in the stomach, e.g. aspirin

Question 24

Where are basic drugs better absorbed?

Answer 24

in the intestines

Question 25

Where are acidic drugs better absorbed?

Answer 25

in the acidic media

Question 26

Where are acidic drugs better excreted?

Answer 26

in the basic media

Question 27

Where are basic drugs better absorbed?

Answer 27

in the basic media

Question 28

Where are basic drugs better excreted?

Answer 28

in acidic media

Question 29

In what tissue layer are vaccines administered into?

Answer 29

vaccines

Question 30

What are less common routes of drug administration?

Answer 30

Topical Transdermal Inhalational Intrathecal

Question 31

What are the more common tissue layers for drug administration?

Answer 31

subcutaneous | intradermal, intramuscular, intravenous

Question 32

What are the less common tissue layers for drug administration?

Answer 32

Topical Transdermal Inhalational Intrathecal

Question 33

Between what levels is ideal dosing of a drug achieved?

Answer 33

below the MTC but above the MEC

Question 34

Is 250mg of paracetamol four times a day optimal?

Answer 34

no because it is below the MEC so it'll be ineffective

Question 35

Is 3g of paracetamol four times a day optimal?

Answer 35

no because it is above the MTC so it could be dangerous

Question 36

What are the pharmacokinetic concepts?

Answer 36

``` Absorption First-pass (pre-systemic metabolism) Bioavailability Bioequivalence Volume of distribution Cytochrome P450 enzyme system Half-life Steady state Clearance ```

Question 37

What is the maximum dosage of paracetamol four times a day?

Answer 37

8x 500mg tablets a day

Question 38

Will Crohn’s disease change the effectiveness of a contraceptive oral pill taken on a daily basis?

Answer 38

yes bc crohns can impair absorption

Question 39

What is the equation for calculating Bioavailability?

Answer 39

oral AUC / IV AUC

Question 40

What is the bioavailability of IV AUC?

Answer 40

100% bc all of it is directly entered into the bloodstream so all of it is absorbed

Question 41

Which method has a higher bioavailability, oral or IV?

Answer 41

IV bc not no drug administered orally will make it into the blood 100%, while IV will

Question 42

Which method has a higher bioavailability, oral or IV?

Answer 42

IV bc not no drug administered orally will make it into the blood 100%, while IV will

Question 43

If a drug has an oral bioavailability of 20%, how will the oral dose be adjusted to achieve therapeutic effectiveness?

Answer 43

it will be ~5x higher than the corresponding IV dose

Question 44

What is furosemide used to treat?

Answer 44

high bp, HF and oedema

Question 45

Why does congestive heart failure decrease the bioavailability of an orally administered drug?

Answer 45

bc congestion in the heart also causes the organs to have oedemas, including in the gut this increases the distance the drug has to travel through the gut to get into the bloodstream

Question 46

What is the most suitable route of administration of drugs for stable HF?

Answer 46

orally

Question 47

What is the most suitable route of administration of drugs for decompensated HF?

Answer 47

IV

Question 48

What type of medication is furosemide?

Answer 48

a diuretic

Question 49

What is the most appropriate route of administration of drugs for a patient with severe CAP and why?

Answer 49

IV bc bioavailiability is 100% and quick treatment is needed as they are very ill if it is SEVERE CAP

Question 50

What is the most appropriate route of administration of drugs for a patient with CAP and why?

Answer 50

orally

Question 51

What are examples of bacterial infections Amoxicillin is used to treat?

Answer 51

pneumonia, skin infections, and UTIs

Question 52

How is Amoxicillin administered?

Answer 52

orally, less commonly by injection

Question 53

Which pharmacokinetic parameter(s) is/are affected if a patient for osteoperosis takes alendronic acid at least 30 minutes before breakfast?

Answer 53

bioavailability and absorption | the bioavailability would already have been low (20-30%) but the food would reduce it further

Question 54

What is the first pass metabolism otherwise known as?

Answer 54

pre-systemic metabolism

Question 55

What is the effect of a high first pass effect on bioavailability?

Answer 55

it reduces BAVT

Question 56

What is the effect of a low first pass effect on bioavailability?

Answer 56

it increases BAVT

Question 57

Why is the sublingual route of drug administration suitable for a patient with stable angina?

Answer 57

bc it will bypass the GI tract and be administered directly to the blood stream instead it will be exposed to extensive first pass metabolism

Question 58

What type of medicine is glyceryl trinitrate?

Answer 58

a nitrate

Question 59

What is GTN used to treat?

Answer 59

angina - can help stop chest pain if an angina attack has already started. It can also help to prevent them from starting

Question 60

What can GTN ointment be used to treat?

Answer 60

tears in the skin around the bottom (anal fissures)

Question 61

How can GTN be administered?

Answer 61

tablets, spray under tongue | patches and ointment on skin

Question 62

When might GTN patches be used and for what purpose?

Answer 62

in hospital to make veins easier to see if administering a drip (infusion)

Question 63

Why might it be a concern that a patient on propranolol for hyperthyroidism has deranged liver function?

Answer 63

?

Question 64

What type of substance is propranolol?

Answer 64

a non-selective beta blocker

Question 65

When are two drugs considered bioequivalent?

Answer 65

when there is no significant difference in the rate or extent of bioavailability at the same molar dose and under the same conditions

Question 66

When might the bioequivalence of two drugs be relevant?

Answer 66

Different formulations from different companies | Different batches of drugs from the same company