Flashcards in Pharmacokinetics One and Two Deck (37):

1

## What are the basic pharmacokinetics perameters?

###
Bioavailibility

Volume of distribution

- Loading Dose

Plasma Clearance

- Maintanence dose

Half life

-accumulation

2

## What is pharmacokinetics?

###
The study of ADME on a quantitative basis

-How drug concentrations change with time from administration

3

## What is the true definition of pharmacokinetics?

### Pharmacokinetics is the study of drug concentrations time profile in the body

4

## What is the basic time course of a drug?

###
Absorption

Distribution

(metabolism or) Excretion

5

## What is drug absorption?

### Process by which the unchanged drug moves from the site of administration into systemic circulation

6

## What is drug absorption relevant for?

###
Non-vascular administration (not-intravenous (IV))

- Oral (po)

- Subcutaneous (sc)

- Intramuscular (im)

- Rectal (pr)

- (sublingual)

7

## What is bioavailibility?

### The fraction of unchanged drug that reaches systemic circulation (out of dose administered- some may break down or be excreted-known as first phase effect)

8

## What is the equation for bioavailibility?

###
F = AUCpo x DOSEiv

AUCIV DOSEpo

AUC = Area under plasma concentration curve vs time

F is constant, so you can change the doseage and to change the AUC, but F will always be the same

9

## What is the first phase effect?

### Loss of drug occurring before the drug reaches systemic circulation

10

## What are the three pharmacokinetic parameters?

###
Volume of distribution

Plasma Clearance (cl)

Plasma half life (T0.5)

11

## What is distribution?

### Processes involved in delivery of the drug to the tissues via the arterial blood. (general circulation to tissue)

12

## What defines distribution?

### The parameter known as volume of distribution

13

## What is the equation for the volume of distribution?

###
V = Amount of drug in the body

Plasma drug concentration

14

## What are the determinants for the volume of distribution?

###
Blood Flow

Body mass and composition

Physicochemico properties of the drug

Tissue binding

Drug binding to plasma proteins (decreases v)

15

## What is the loading dose?

### The first dose a drug treatment, required to reach the target concentration RAPIDLY

16

## What is the equation of LD(mg)?

###
LD = V(L) x target concentration (mg/L)

Two factors must be known

17

## What is drug elimination?

### The irreversible removal of drug from the body

18

## What process can occur to cause drug elimination?

###
Drug metabolism (conversion of drug into another chemical species)

Drug excretion (loss of drug in bile or urine)

19

## What is the definition of clearance?

### Volume of plasma drug cleared per a unit time (L/h)

20

## What is the equation for elimination rate?

### CL x concentration = elimination rate

21

## What is the equation for clearance?

### Cl= Dose / AUC

22

## What is the definition of maintenance dose(MD)?

### Dose rate to achieve and maintain a target concentration

23

## What is steady state?

### When dose rate in= rate of elimination

24

## What is the equation for MD?

### MD (mg/h) = CL (l/h) x Target concentration (mg/L)

25

## What is half life?

### The time required for drug concentration to halve

26

## What does half life depend on?

### Volume and clearance

27

## Is half life variable?

### Usually constant irrespective of drug concentration

28

## What is the concentration of drug in the body related to?

### The number of half lives that have occured since the time of administration

29

## If the half life is known then what is it possible to calculate?

###
How much drug is left in the body

How long it will take to reach steady state

30

## What is the equation for half life?

### T0.5 = 0.7 V/Cl

31

## after four half lifes how much drug will have been eliminated?

### more than 90%

32

## What does half lives help predict?

### When the therapeutic or toxic drug effect is likely to cease

33

## How many half lives is considered the point where a negligible amount of drug remains in the system?

### Four half lives

34

## What is accumulation?

### When after repeated dosing or infusion, the drug will accumulate in the body until input rate= elimination rate (steady state)

35

## When does steady state occur?

### Drug accumulation is complete(no longer occurring) and concentrations have plateaued (low level of drug)

36

## How many half lives does it usually take to reach steady state?

### Four

37