Pharmokinetics

Question 1

What are the enteral methods of drug administration

Answer 1

Oral
Rectal
Sublingual (under the tongue)

Question 2

What are the parenteral methods of drug administration

Answer 2

Subcutaneous (under the skin)
Intramuscular
Intravenous

Question 3

What is pharmokinetics

Answer 3

The kinetic change of the drug in the body overtime

Question 4

What is first pass metabolism

Answer 4

Enteral drugs would pass through the liver and they would be metabolised before hey pass through to the systematic circulation

Question 5

What is the transcellular and the paracellular drug movement

Answer 5

Transcellular is through the cells
Paracellular is between the cells

Question 6

What is distribution

Answer 6

The movement of the drug in systematic circulation and to the tissues and the organs

Question 7

What is bioavailability

Answer 7

The amount of drug that would pass through to the systematic circulation and into the tissues

Question 8

How do you calculate bioavailability through the graphical information

Answer 8

Fo = AUC (oral) / AUC (intravenous)

Question 9

What conditions are necessary for a drug to pass through the membrane

Answer 9

Small
Unionised
PH
Hydrophobic
Lipid based (lipodicity)

Question 10

What conditions would be needed for a drug to be unionised

Answer 10

Acid PH environment and weak acid drug = unionised
Basic PH environment and weak base drug = unionised

Question 11

What does the Henderson-hasslebalch equation show

Answer 11

The estimated PH

Question 12

What is the Henderson-Hasslebalch equation for acids and bases

Answer 12

PH - PKA = ionised / unionised (acids)
PH-PKA = unionised / ionised (bases)

Question 13

What factors would influence the drug dosage

Answer 13

Body surface area
Mass
Age (older you get the lower the amount of water in the body)

Question 14

How would you calculate the volume distributed

Answer 14

Vd = drug dosage / plasma concentration

Question 15

What is important about plasma proteins

Answer 15

Can bind to the drugs
Albumin can bind to the acidic and neutral drugs
AAG (glycoprotein) binds to the basic drug

Question 16

What is the transmission time and suitable PH for the small intestine

Answer 16

3-5 hours
PH 6-7

Question 17

What is important about the small intestine

Answer 17

The main area for drug absorption

Question 18

What contributes to elimination

Answer 18

Metabolism and excretion

Question 19

What is the main metabolising enzyme that would metabolise 50% of all the top drugs

Answer 19

CYP3A4

Question 20

What is the extraction ratio

Answer 20

That amount of the drug that would be metabolised and removed from the body

Question 21

What does it mean if the extraction ratio is high

Answer 21

Large amount of drug would be metabolised and released from the body

Question 22

What does it mean if the extraction ratio is low

Answer 22

Low amount of drug would be metabolised and removed from the body

Question 23

What is meant by clearance

Answer 23

The volume of fluid or blood from which a drug would complete be removed

Question 24

What would happen to the clearance is there was renal or hepatic failure

Answer 24

The clearance would decrease as would have no functioning liver or kidney to remove the drug from the blood and the fluid

Question 25

What are the inhibitors and the inducers of enzyme action

Answer 25

Inhibitors would reduce the amount of drug that is metabolised (for example grape fruit juice) Inducers would increase the rate of drug metabolism (st johns wort)

Question 26

What causes the half life to increase

Answer 26

Decreased clearance Decreased volume distribution

Question 27

What is half life

Answer 27

The amount of time taken for the concentration of drug to half

Question 28

What is first order kinetics

Answer 28

The rate of break down and the concentration of the drug would be directly proportional

Question 29

What it is the loading dose

Answer 29

The first dose that would be give to patients This would be larger then the normal dose as would want to reach the therapeutic dose level and then allow this level to be maintained

Question 30

What would happen in the body if there was no drug clearance

Answer 30

Drug accumulates, toxicity of the drug, death

Question 31

What is liver perfusion

Answer 31

The amount of drug that would move through the liver within the blood or in the plasma (fluids)

Question 32

When is perfusion important

Answer 32

When would have a high extraction Means large amount would pass through the liver Low amount of active drug within the body

Question 33

When is perfusion not important

Answer 33

When there is a low extraction The amount that passes through the liver would not matter not a lot would be metabolised Large amount of the active drug would be in the body

Question 34

What is drug metabolism by oxidation

Answer 34

Changing the functional group Makes the molecule polar Can be removed by the renal system

Question 35

What is drug metabolism by conjugation

Answer 35

Adding a functional group Allows the molecule to increase in size Less polar Then can have billiary excretion (in stool)

Question 36

How would the use of St. John’s wort (a CYP 3A4) effect the plasma concentration and why

Answer 36

Decreases the plasma concentration Would allow the increased metabolism of the drug,so would have less available in the system

Question 37

What methods are used in transcellular movement of drugs (through the cells)

Answer 37

Diffusion Carrier mediated transport Bulk transport Endocytosis