Pharmacokinetics

Question 1

volume w/in body necessary to account for the initial concentration of drug in plasma following a given dose
(no actual anatomical correlate)

Answer 1

Volume of Distribution

Question 2

drugs with ____ Vd undergo limited distribution.

In the case of IV doses, they will?

Answer 2

low

remain in the bloodstream

Question 3

When the rate of drug moving into the tissues greatly exceeds the rate leaving tissues, Volume of Distribution will be

Answer 3

large

drug accumulates outside of bloodstream

Question 4

Is there an upper limit for Volume of Distribution

Answer 4

no

Question 5

What conditions can affect the animals normal Vd?

Answer 5

edema, liver disease (reduction in plasma proteins)

Question 6

In zero order kinetics, the drug will be eliminated at a ______

Answer 6

constant rate (unrelated to concentration)

Question 7

When is the amount of drug eliminated proportional to its concentration?

Answer 7

1+ Orders

Question 8

What time of kinetics is safer with regards to elimination and total body burden?

Answer 8

1+ order

BUT any can convert to zero order when SATURATED

Question 9

When is half life constant for a drug?

Answer 9

when it obeys 1st order kinetics

Question 10

Two phases of drug transport after dosing?

Which is used for calculations?

Answer 10

Redistribution(alpha) & elimination (beta)

Elimination!

Question 11

Using half lives is helpful for predicting levels ______________ but not ______________

Answer 11

in blood

not in tissues

Question 12

time to achieve ___________ in plasma depends solely ON THE HALF LIFE

Answer 12

Steady-State Concentrations

Question 13

What does Steady-state plasma concentration mean?

Answer 13

concentration is fluctuating in a consistent way (peaks and troughs stay the same for 6 half-lives)

Question 14

Requires approximately ____ half-lives of sustained drug administration to achieve steady-state

Answer 14

5

Question 15

Giving dosage more frequently will _______ both the peaks and troughs and vice versa for less frequent dosage.

Answer 15

elevate

ratio Cpmin/Cpmax is increased however

Question 16

How will increasing the dose affect the peaks and troughs(Cpmax and Cpmin)?

Answer 16

elevate both

Question 17

How does giving a dose more frequently affect the accumulation in a tissue?

Answer 17

increase accumulation

Question 18

How is accumulation affected by dosing interval?

Answer 18

less frequent dosing -> less accumulation

vice versa

Question 19

R (accumulation factor) is a function of ?

Answer 19

ratio of dose interval / drug half life

Question 20

What is a function of the dose interval relative to half-life?

Answer 20

R(accumulation factor) but also peak-to-trough concentration (Cpmax55:Cpmin55)

Question 21

When dosing interval equals the half-life Cpmin is ________ Cpmax

Answer 21

1/2

Question 22

When the dosing interval equals 2 half, Cpmax is ________ Cpmin

Answer 22

4x

Question 23

How will steady state be affected by slow absorption?

Answer 23

reduces both peak and trough levels