Pharmacokinetics

Question 1

After 5 half lives _______% of the drug is gone.

Answer 1

After 5 half lives 97% of the drug is gone.

_________________

Unlikey to have any more effect

Question 2

Most drugs in veterinary medicine follow _________ kinetics

Answer 2

Most drugs in veterinary medicine follow First Order kinetics

Question 3

Half-life (T_1/2) equation

Answer 3

t_1/2 = 0.693 x Vd / Cl_B

Question 4

When saturation occurs, Cl_B (increases/decreases) and t_1/2 (increases/decreases) leading to drug accumulation and potential development of side effects.

Answer 4

When saturation occurs, Cl_B (increases/decreases) and t_1/2 (increases/decreases) leading to drug accumulation and potential development of side effects.

Question 5

T/F: Half life is dose dependent

Answer 5

False, it is proportional

Question 6

Dosage

Answer 6

“Recipe” for how much to give (mg/kg)

Question 7

Bioavailability % (F%) equation

Answer 7

F% = AUC (extravascular) / AUC (IV) x 100%

Question 8

F% is equal to ________ for IV administration

Answer 8

F% is equal to 100 for IV administration

Question 9

One Compartment Model

Answer 9

Consider the body as consisting of a single, homogeneous compartment. Volume would equal the volume of distribution. Model may be closed or open taking in account for clearance.

Question 10

Primary compartment method by which pharmacokinetic parameters are now determined in veterinary medicine

Answer 10

Stochastic model

(Non-Compartmental)

Question 11

Zero Order Kinetics

Answer 11

Amount of drug is eliminated per unit time is fixed

Question 12

Peak

Answer 12

Highest concentration of each dose

Question 13

Dose

Answer 13

The amount of a drug given to an individual (mg)

Question 14

Time to achieve steady state levels is (dependent/independent) of dose.

Answer 14

Independent

Question 15

What are the components of a dosage regimen

Answer 15

Dosage

Route of Administration

Frequency

Duration

Question 16

Plasma Concentration Steady State is reached at how many half lives

Answer 16

5

Question 17

Extent

Answer 17

How much the mass (dose) of a drug changes in total

Question 18

Loading Dose

Answer 18

Single dose administered to get the plasma concentration to a certain level, to be maintained by repeated dosing

Question 19

Compartment Model

Answer 19

Views the patient as a number of compartments, each compartment is a collection of tissues that have similar pharmacokinetics

Question 20

Pharmacokinetics

Answer 20

Use of mathematical modelsto quantitate the time course of drug disposition in man and animals

Question 21

Allometric Scaling

Answer 21

Uses pharmacokinetic data in multiple species to try to predict the behavior of a drug in a species for which this information is unknown

Question 22

What type of pharmacokinetic model is used for drugs that follow first order kinetics?

Answer 22

Non-Linear Model

Question 23

Clearance

Answer 23

Volume cleared of the drug per unit time (mL/min/kg)

Question 24

What happens to plasma concentration and half life if a dose is doubled?

Answer 24

Plasma concentration will increase

Half life will remain the same

Question 25

Population Pharmacokinetics

Answer 25

System estimates pharmacokinetics by looking at populations. Mathematical techniques allow studies of large numbers of animals with less individual sampling. Can allow for development of parameters for a drug that would apply to all breeds/ages/genders/etc.

Question 26

Elimination roughly equals

Answer 26

Metabolism + Excretion

Question 27

As Vd increases, t_1/2 (increases/decreases)

Answer 27

Increases

Question 28

Multi-Compartment Model

Answer 28

Consists of multiple compartments. Math gets incredibly complex

Question 29

Vd Equation

Answer 29

Vd = Dose / C_p

Question 30

Bioavailability (F)

Answer 30

Fraction of the dose given which finds its way into systemic circulation

Question 31

Intermittent Dosing Cp^ss Equation

Answer 31

_DOSE x F_ = Cp^ss x CL_B ## Footnote Interval

Question 32

Two Compartment Model

Answer 32

Considers the body as consisting of two compartments; a central compartment into which the drug is added and from which it is clear and a second compartment to which the drug distributes. Graphical representation shows a distribution and elimination phase.

Question 33

Dose_CRI Equation

Answer 33

= Cp^ss x CL_B

Question 34

As Clearance increases, t_1/2 (increases/decreases)

Answer 34

Decreases

Question 35

Trough

Answer 35

Lowest concentration of each dose

Question 36

Describe the pattern of Plasma Concentration of a drug in relation to Plasma Elimination of a drug

Answer 36

Plasma concentration will follow the same pattern as plasma elimination, only upside down \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ 1 half life - 50% of final Cp^ss 5 half lives - Cp^ss will be 97% of eventual steady state

Question 37

Apparent Volume of Distribution (Vd)

Answer 37

Theoretical volume a drug would occupy if it was evenly distriuted through the body at the same concentration as in plasma

Question 38

First Order Kinetics

Answer 38

Proportion of drug eliminated per unit time is fixed

Question 39

Elimination Rate Constant

Answer 39

Fraction/ Proportion of the drug that would be eliminated per unit time

Question 40

Volume of Distribution (Vd)

Answer 40

Volume of drug would occupy if it was evenly distributed at the same concentration as in plasma (L/kg)

Question 41

Very high Vd ( \> L/kg ) suggests that a drug is

Answer 41

Very high Vd ( \> L/kg ) suggests that a drug is **distributing preferentially to tissue and may even be sequestered somewhere**

Question 42

Total Body Clearance (CL_B)

Answer 42

Volume of distribution of drug in body cleared of teh drug per unit time (mL/min/kg) and this is the sum of clearance by the kidneys, liver and everywhere else. \_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_\_ Takes into account both metabolism and excretion

Question 43

Bioavailability (F) equation

Answer 43

F = AUC ( extravascular ) / AUC (IV)

Question 44

Very low Vd suggests that a drug is

Answer 44

Very low Vd suggests that a drug is **not being distributed to all of the tissues**

Question 45

After 2 half lives \_\_\_\_\_\_\_% of the drug is gone.

Answer 45

After 2 half lives **75**% of the drug is gone.

Question 46

Bioequivalence

Answer 46

Different formulations of the same drug have the same drug bioequivalence when they are absorbed to a similar extent and similar rate

Question 47

Stochastic Model | (Non-Compartmental)

Answer 47

Involve using analysis of large numbers of actual animal data (time-plasma curves).

Question 48

Elimination Half Life

Answer 48

Time required for the drug concentration to decrease by one half or 50%

Question 49

Rate

Answer 49

How fast the mass (dose) of a drug changes per unit time (mg/min)

Question 50

Bioavilability is a measure of

Answer 50

Bioavilability is a measure of **drug exposure**

Question 51

What measurements are important to compare in bioequivalence

Answer 51

AUC C_max T_max

Question 52

Mean Resistance Time (MRT)

Answer 52

Used in the non compartment model, describes the length of drug persistence in the body

Question 53

Plasma Concentration at Steady State Cp^ss

Answer 53

Concentration at which the amount of drug going in is equal to the amount going out

Question 54

After 3.3 half lives \_\_\_\_\_\_\_% of the drug is gone.

Answer 54

After 3.3 half lives **~90**% of the drug is gone.