Lecture 4 1/29/24

Question 1

What are the mechanisms for avoiding first pass metabolism?

Answer 1

-sublingual admin.
-nasal admin.
-rectal admin.

Question 2

What is drug distribution?

Answer 2

reversible transfer of drug between plasma and tissues

Question 3

What characteristics of distribution affect therapeutic effect?

Answer 3

rate and extent of distribution

Question 4

What factors affect drug distribution?

Answer 4

Uncharged Drugs:
-tissue perfusion rate
-specific tissue affinity
Charged Drugs:
-degree of polarity and ionization
Both:
-protein binding in plasma and tissue
-molecular size

Question 5

How does perfusion rate relate to delivery of the drug?

Answer 5

organs with high perfusion rates will receive a greater proportion of the drug per unit time

Question 6

What are the characteristics of specific tissue affinity?

Answer 6

-affinity of drugs for a specific tissue
-may require specific receptors or transport systems
-increased time to distribution equilibrium

Question 7

What are the special tissue sites that rely on polarity/ionization to keep drugs/molecules out?

Answer 7

• brain (blood-brain barrier)
  -prostate and testes
  -joints
  -placenta and mammary glands
  -ocular compartments

Question 8

What are the characteristics of plasma proteins and drug binding?

Answer 8

-albumin binds neutral and acidic drugs
-alpha1 acidic glycoprotein binds basic drugs
-hormone transport proteins bind steroids, thyroxin, testosterone
-lipoproteins bind very lipophilic pesticides

Question 9

Which drugs distribute mostly in plasma?

Answer 9

drugs with a volume of distribution close to plasma volume

Question 10

Which drugs distribute in the plasma and interstitial space?

Answer 10

drugs with a volume of distribution close to extracellular water

Question 11

Which drugs distribute in the body spaces?

Answer 11

drugs with a volume of distribution close to total body water

Question 12

Which drugs distribute mostly in tissue?

Answer 12

drugs with very high volumes of distribution

Question 13

What are the characteristics of C0?

Answer 13

-calculated
-identifies where the slope would cross the y axis at time zero

Question 14

What are the characteristics of Cmax?

Answer 14

-measured
-highest detectable concentration
-can occur at any time

Question 15

What does a higher Cp0 compared to dose indicate?

Answer 15

a lower volume of distribution

Question 16

What factors can impact drug binding in plasma?

Answer 16

-age
-breed
-nutritional status
-renal disease
-liver disease
-drug interactions

Question 17

What happens when one drug displaces another drug from binding to plasma proteins?

Answer 17

more of the displaced drug is available for use in the free state