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Flashcards in Topic 2 Deck (17):
1

What is the relationship between the rate at which a drug moves from stomach to intestine/absorption rate/extent

the faster a drug moves from the stomach to the small intestine, the faster it will be absorbed and the more it will be absorbed.

2

Delays in the passage of drugs from the stomach (gastric emptying) are usually due to

the presence of large amounts of food, especially fatty foods that take longer to be broken down.

3

Example of food delaying the passage of drugs

alcohol, when taken on an empty stomach is absorbed more quickly and to a greater extent than when taken with food, particularly fatty foods that delay gastric emptying.

4

What is a food/drink that speeds up gastric emptying and increases the rate of alcohol absorption

carbonated drinks (like champagne or sparkling wines)

5

Some of the alcohol is metabolised in the stomach meaning

the longer it takes it to move to the intestines, the less is absorbed.

6

In some situations, passage through the digestive tract may be too rapid due to

an increase in intestinal motility (movement of substances through intestinal tract), e.g. during diarrhoea

7

When the passage in the digestive tract is too rapid, what is the effect on the absorption

absorption is likely to be decreased as the drug passes to rapidly through the small intestine.

8

Bioavailability

the amount of drug that is absorbed into the general or systematic circulation following oral administration. [what percentage of a drug ends up in the bloodstream]

9

What is the bioavailability considered to be for intravenous injections

100%

10

What factors are important determinants of the rate and extent of absorption of drugs (4)

1) thickness of cell layers through which the drug must pass
2) lipid solubility of the drug
3) concentration of the drug
4) area of the absorbing surface

11

For drugs taken orally, what factors are important determinants of the rate and extent of absorption of drugs

1) thickness of cell layers through which the drug must pass
2) lipid solubility of the drug
3) concentration of the drug
4) area of the absorbing surface
5) susceptibility to the contents of the digestive tract
6) the time taken to move from the stomach to the intestines (which may influence the rate and extent of absorption i.e. the the rate of gastric emptying)
7) intestinal motility
8) susceptibility to liver enzymes (first pass metabolism)

12

Side effects occur during which stage (ADME)

distribution

13

What is distribution

where in the body the drug goes

14

When do side effects occur

when a drug has an effect in an organ other than the target organ

15

Example of side effects

for pain reliever, the target organ may be a sore muscle in the leg but irritation of the stomach could be a side effect.

16

Drugs act free when ..., meaning ....

in bloodstream and potential for off-target effects as drug is in systematic circulation

17

What is distribution dependent on (2)

drug properties (e.g. fat solubility, water solubility, protein affinity); and dependent on the body (e.g. blood brain barrier, fat composition, plasma proteins)