Pharmokinetics

Question 1

What are the positives of oral administration?

Answer 1

Convenient, economic, safety

OD and severe allergic rxn are less likely

Question 2

What are the negatives of oral administration?

Answer 2

Patient compliance, may not reach optimum concentration

Question 3

What are the most important sites of absorption for oral drugs?

Answer 3

Stomach and small intestine

Question 4

What structures are lined with endothelium?

Answer 4

Heart, blood vessels, lymphatics, and serous cavities

Question 5

Most drugs need to be _____________ enough to pass through a cell membrane.

Answer 5

Lipophilic

Question 6

What is a partition coefficient?

Answer 6

Measures ability for drug to diffuse

Larger PC = more likely it will be absorbed

Question 7

T/F: Charges and polar moities will make molecules less likely to diffuse through the cell membrane.

Answer 7

True

Question 8

What is the stomachs pH at rest? RIght after a high protein meal?

Answer 8

Rest: 4-5

Post-meal: 1-2

Question 9

Molecules with a low pKa (acidic) will be absorbed better in the ________.

Answer 9

Stomach

Question 10

Molecules with a high pKa (bases) will be absorbed better in the __________.

Answer 10

Small intestine

Question 11

________ are always open but _________ only let things in when they’re activated.

Answer 11

Pores; channels

Question 12

____________ use ATP and are often used to kick proteins out of cells.

Answer 12

ABC transporters

*if over-expressed - will lead to drug resistance

Question 13

_____________ exchange Na+ or K+ and are important for transport of certain drugs that are organic acids or bases.

Answer 13

SLC transporters

Question 14

What are two major factors that make the small intestine better for absorption?

Answer 14

1. More surface area

2. More time (6-8 hrs)

Question 15

T/F: Gastric emptying can take longer with food.

Answer 15

True

Question 16

Why do some drugs absorb better when given intramuscularly or subcutaneously than when taken orally?

Answer 16

Capillaries in these areas have gaps in their endothelium making it easier to get into the bloodstream

Question 17

What is the volume of distribution?

Answer 17

Provides an indication of how a drug is distributed

Administered amount/concentration in plasma

Question 18

If a drug has a volume of distribution of 3 L, where is the drug in the body?

Answer 18

Just sitting in the plasma

Question 19

What would you expect the volume of distribution to be of a drug that is in the blood and interstitial space but not in the cells?

Answer 19

12 L

3L in plasma, 9L in interstitial space

Question 20

If a drug has a distribution volume that is very very high what does this mean?

Answer 20

There is a very low concentration in the blood plasma - the drug has gone somewhere else

Question 21

T/F: Drugs which are more polar, more highly ionized, and with high plasma binding capabilities will have higher volumes of distribution.

Answer 21

False

Non-polar, low rates of ionization, low plasma binding capabilities

Question 22

T/F: Volume of distribution will be decreased during dehydration.

Answer 22

True

Question 23

_________ are membrane bound enzymes that metabolize drugs.

Answer 23

Microsomes

Question 24

Where are microsomes found?

Answer 24

Smooth E.R. Of hepatocytes

Question 25

What is the main goal of a microsomes?

Answer 25

Make drugs more water soluble

Oxidation, reduction, hydrolysis, or dehalogenation

Question 26

What is Phase II of metabolism in the liver?

Answer 26

Glucuronide conjugation

Usually inactivates the drug

Question 27

Why is non microsomal metabolism useful?

Answer 27

When the drug mimics natural substance

Question 28

For most drugs, what is the longer phase of metabolism: getting the drug to the liver, or the actual chemical metabolism?

Answer 28

Getting the drug to the liver is slow; chemical metabolism is fast

Question 29

The ___________ is a major filter during glomerular filtration.

Answer 29

Basement membrane

Question 30

T/F: Drugs that are filtered will clear much faster than drugs that are secreted.

Answer 30

False

Secretion of drugs is much faster than filtration

Question 31

What is the difference between pharmacokinetic differences and pharmacodynamic differences?

Answer 31

Pharmacokinetic: one dose reaches dif concentration in dif people

Pharmacodynamic: drug present at given concentration in plasma has different responses in different people

Question 32

T/F: Predicting dosing complications in children is similar to that in adults.

Answer 32

False

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