Ch.7: Principles of Pharmacokinetics Flashcards Preview

Pharmacology > Ch.7: Principles of Pharmacokinetics > Flashcards

Flashcards in Ch.7: Principles of Pharmacokinetics Deck (16):
1

AMDUCA*

Animal Medicinal Drug Use Clarification Act. Provided legal basis for ELDU by vets

2

key PK properties for a drug (4)*

-bioavailability (F)
-volume of distribution (Vd)
-clearance (Q)
-elimination half-life (t1/2)
**can be changed by disease processes or other conditions (aging)**

3

bioavailability*

the fraction of the drug that is absorbed and gets into the bloodstream relative to the amt. that would get into the bloodstream if you gave it by direct IV injection (a fractional measure)

4

In the formula Vd = total body drug dose/plasma conc. Plasma conc. refers to what?*

the expected highest plasma conc. that will be achieved with the drug

5

T/F: IV doses remain primarily in the bloodstream with drugs that have a low Vd. What are the causes of this?*

T. causes include poor permeability, high water solubility, high protein binding, limited diffusion in tissues

6

Name 1 drug with high Vd*

Propanolol

7

Name 1 drug with low Vd*

Theophylline

8

Chars. of zero order kinetics*

-drug eliminated at constant rate
-rate of drug elim. is unrelated to drug conc.
-potentially dangerous
-rare for the drugs we use

9

Chars. of first order kinetics*

-drug elim. at exponential rate
-fixed fraction of drug eliminated per unit time
-rate of drug elim. is proportional to drug conc.
-safer
-**can convert to zero order kinetics if elim. process becomes saturated**

10

Reasons for prolonged drug treatment*

1) drug therapy controls symptoms, but doesn't cure the underlying dz
2) drug cures the dz, but therapeutic success requires prolonged exposure to drug

11

The time required to achieve steady-state drug conc. in plasma depends solely on the ___ of the drug*

half-life

12

when are loading doses used?*

a larger dose of drug given for initial dose to bump up the plasma conc. so it doesn't take so long to reach a steady state

13

Steady-state levels of peak and trough drug conc. are determined by:**

drug dose and dosing frequency (interval)

14

Factors that alter steady state*

-slow absorption
-PO admin.
-irregular doses
-missed doses

15

2 approaches used to alter dosing regimen when drug is primarily cleared by the kidney*

-interval extension
-dose reduction

16

2 common methods for altering dose regimens*

1) individualized regimen (based on actual drug levels in the patient)
2) creatinine clearance (compared to normal urinary levels)