Lecture 2 & 3 - Pharmacokinetics (PK) and Drug Disposition Flashcards Preview

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Flashcards in Lecture 2 & 3 - Pharmacokinetics (PK) and Drug Disposition Deck (131)
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1

Pharmacokinetics

what the body does to a drug

*study of how the body absorbs, distributes, metabolizes, and eliminates (ADME) a drug over time

2

ADME ?

Absorption
Distribution
Metabolism
Elimination/Excretion

3

Where does 1st pass effect occur?

stomach

4

Primary site for absorption?

small intestine

5

____ ______ is key for distribution

blood stream

6

Primary site for metabolism?

liver

7

Primary site of excretion

kidney

8

What is the clinical goal from using and understanding pharmacokinetics?

-enhance efficacy
-decrease toxicity

9

Drug effect related to concentration at ??

site of action

10

For more drugs, the concentration at the site of the _____ determines the intensity of a drug's effect

receptor

11

In order for drugs to move through the body they must cross cell membranes. What are the 3 ways they can do that?

1-pass through channels or pores

2-passing through the membrane with the aid of a transport system

3-penetrating directly

12

Where are transporters found?

liver
kidneys
intestines
brain capillaries

13

Out of the 3 types of drug movement, which is the most common?

direct penetration

14

Why does the movement through the body for most drugs depend on ability for direct penetration? (2 reasons)

-most drugs are too large to pass through channels

-most drugs lack transport system to help them cross cell membranes

15

In order to penetrate cell membranes directly, a drug must be _____

lipophilic

16

Difference between one and two compartment model?

One-compartment model:
-drug is administered, immediately distributed, and then can be metabolized and excreted

Two-compartment model:
-some drugs do not distribute instantaneously to all parts of the body
-it goes to individual organs first, and then gets distributed to the peripheral part of the body afterwards

17

Drugs that don't extensively distribute into extravascular tissues (drugs that aren't stored) are well described as ?

one-compartment models

18

Drugs that do extensively distribute into tissue (drugs that are stored in tissues) are well described as ?

two-compartment models

19

bioavailability (absorption)

fraction of unchanged (unmetabolized) drug reaching the systemic circulation following administration by any route

20

drug accumulation

inversely proportional to dose lost

21

Vd (volume of distribution)

measure of apparent space in the body available to contain the drug - how the drug is distributed in the body relative to plasma

22

clearance refers to ???

metabolism and excretion

23

Clearance (metabolism and excretion)

measure of ability of the body to eliminate the drug

volume of drug per unit of time that gets excreted

24

drug half life (T1/2)

time required to change the concentration of the drug present in the body by one half during elimination

25

Formula for:
bioavailability

AUC admin route / AUC(IV) x 100

OR

AUC oral / AUC injected x 100

26

Formula for:
drug accumulation

accumulation factor = 1/dose lost

27

Formula for:
Vd

amount of drug in body (mg) / conc of drug in plasma (mg/L)

answer expressed in L

28

Formula for:
clearance (Cl)

Cl = (0.693 / t1/2) x Vd

29

Formula for:
drug half life (T1/2)

t1/2 = (0.693 X Vd) / Cl

30

bioavailability (absorption) is the transfer of drug from ______ to ______

site of administration

to

bloodstream