DRUG ABSORPTION AND DISTRIBUTION

Question 1

What is pharmacodynamics?

Answer 1

The study of how a medicine acts on a living organism

Question 2

What are some ways in which we can eliminate drugs?

Answer 2

Through the kidneys, faeces, milk and sweat and expired air

Question 3

What does teratogenic mean?

Answer 3

Anything that disturbs the development of the foetus e.g. drugs which can cross the placenta and affect the foetus

Question 4

Which is the Cmax?

Answer 4

The highest concentration of drug in the blood

Question 5

What is the half life of a drug?

Answer 5

The time at which the drug has lost half its maximum concentration

Question 6

What is the Cmin of a drug?

Answer 6

The lowest concentration of drug in the blood

Question 7

What does the area under the curve of a amount of drug and time graph show?

Answer 7

The amount of exposure that our body has to the drug

Question 8

How could you prevent the drug from disintegrating in the stomach?

Answer 8

By coating it in an acid-resistant coating

Question 9

What is therapeutic drug monitoring?

Answer 9

When you give an estimated initial does and then the therapy is assessed. If the required dose needs to be refined then it will be and the therapy will be assessed again

Question 10

Give an example of how drug absorption can be affected by diet?

Answer 10

Grapefruit juice can affect the rate of absorption

Question 11

What is the ‘volume of distribution’?

Answer 11

A theoretical volume that the total administered drug would have to occupy if it were uniformly distributed to provide the same concentration as it currently is in the blood plasma

Question 12

What are some symptoms of peptic ulcers?

Answer 12

Pain, bleeding, loss of appetite, indigestion, heart burn and vomiting

Question 13

How can you determine where abouts in the GI tract the peptic ulcer is?

Answer 13

If the pain is associated with eating then it’s likely to be in the stomach but if the pain is 2-3 hours after eating then the ulcer is more likely to be in the small intestine

Question 14

Describe the histology of peptic ulcers?

Answer 14

The stomach lining is disrupted which allows the acid in the stomach to degrade the submucosa of the stomach to form tissue damage

Question 15

What are some causes of peptic ulcers?

Answer 15

an infection with Helicobacter pylori (H. pylori) bacteria. Or taking NSAIDS

Question 16

How can H.pylori produce peptic ulcers?

Answer 16

It produces urease which catalysts the hydrolysis of urea to yield ammonia and carbonic acid which induces inflammation and can degrade the submucosa

Question 17

What is gastritis?

Answer 17

Inflammation of the stomach lining

Question 18

Why can NSAIDs cause peptic ulcers?

Answer 18

As they inhibit the COX enzyme which leads to a reduction in prostaglandinlevels which reduces mucus level. This makes the stomach lining more susceptible to suffer from degradation
Aspirin in particular can cause a lot of bleeding as it’s also an anti-platelet therapy

Question 19

What do we give pharmacologically to stop peptic ulcers?

Answer 19

Proton pump inhibitors and histamine inhibitors

Question 20

How do PPIs prevent peptic ulcers?

Answer 20

They cause proton pumps to be absorbed and taken up by parietal cells where they undergo metabolism to cause permensnt inhibition. Only the production of new proton pumps can restore the function of the cell

Question 21

How do histamine inhibitors prevent peptic ulcers?

Answer 21

As histamine produces the key secondary messenger cAMP so, if inhibited, protein kinase A can’t be activated so proton pumps can’t be activated