Drug Absorption

Question 1

Are drugs strong or weak acids/bases?

Answer 1

Weak acids and bases

Question 2

Can ionised drugs cross the cell membrane?

Answer 2

No

Question 3

Can unionised drugs cross the cell membrane?

Answer 3

Yes

Question 4

When will unionised drugs stop crossing the cell membrane?

Answer 4

When they have reached equilibrium

Question 5

Can lipid soluble drugs cross the cell membrane?

Answer 5

Yes

Question 6

What structure must a drug take in order to be taken into cells?

Answer 6

They must resemble naturally occuring compounds

Question 7

Name 3 factors that affect absorption of drugs from the GI tract

Answer 7

Gut Motility
Food
Illness

Question 8

What is first pass metabolism?

Answer 8

Metabolism of a drug before it reaches its site of absorption

Question 9

Where does first pass metabolism occur?

Answer 9

Gut lumen, wall (acid and enzymes), Liver

Question 10

What us bioavailability?

Answer 10

The amount of drug that reaches the circulation and is available for action

Question 11

What are the benefits of IV drugs?

Answer 11

Avoids first pass metabolism

100% bioavailability

Question 12

What are the benefits of Topical drugs?

Answer 12

Avoids first pass metabolism
controlled
local or systemic effects

Question 13

What are the benefits of inhaled drugs?

Answer 13

Drug delivered right to site of action
Rapid
Small doses needed
Little systemic absorption

Question 14

What factors affect bioavailability?

Answer 14

Formulation
Drug’s ability to pass physiological barriers
Gastrointestinal factors
First pass metabolism