F1 ADME & clinical pharmacology 1

Question 1

What is pharmacokinetics?

Answer 1

the time course of a drug from absorption to elimination

determines the drug regimen for a drug - dose, how often

Question 2

What does ADME stand for?

Answer 2

Absorption, distribution, metabolism, excretion

Question 3

What are the 3 mechanisms of drug absorption?

Answer 3

active transport- for drug structurally related to endogenous chemicals
bulk flow of water - small water soluble drug
passive diffusion- movement of most drugs

Question 4

Are weak acids and bases ionised and absorbed in the stomach?

Answer 4

weak acids - unionised therefore absorbed

weak bases - ionised and not absorbed

Question 5

Does presence of food increase time of drug in stomach?

Answer 5

yes

Question 6

Which type of acid drugs have slowed absorption?

Answer 6

acid stable drugs

Question 7

Why are acid labile drugs more readily broken down?

Answer 7

stay longer in stomach

Question 8

Why are PPIs given gesture-resistant capsules?

Answer 8

are acid labile

Question 9

Where is the major site or absorption?

Answer 9

small intestines

Question 10

Do the small intestines have good blood flow?

Answer 10

yes

Question 11

Why are most weak acids & bases absorbed in small intestines?

Answer 11

high levels of uncharged drug

Question 12

What is first pass metabolism?

Answer 12

drug absorbed from small intestines go to liver via hepatic portal vein, some drug metabolised before reaching the systemic circulation

Question 13

How do you calculate bioavailability F?

Answer 13

F= AUC oral/AUC iv

Question 14

How do you calculate single dose?

Answer 14

=amount given/ F

Question 15

What is clearance?

Answer 15

the volume of plasma cleared of a drug in unit time) measure of amount of drug removed by body

Question 16

What are the units for clearance?

Answer 16

(mL/min) use L/h

Question 17

What is volume of distribution (Vd)?

Answer 17

the apparent vol in which a drug is dissolved in a body

Question 18

How do you calculate Vd?

Answer 18

= amount in body/conc

= does/ conc at t=0

Question 19

What does first order kinetic tell us about elimination and concentration of drug?

Answer 19

rate if elimination is proportional to concentration of drug

Question 20

What is the equation of first order kinetics and what does each part represent?

Answer 20

Ct= Coe^-kt 
Ct= conc at t=t 
Co= conc at t=0 
k= rate constant 
t= time

Question 21

What does rate constant mean?

Answer 21

k is the fraction of drug eliminated per unit time

k= clearance/ Vd

Question 22

What is half life?

Answer 22

time for conc to decrease by 50%

Question 23

How do you calculate half life?

Answer 23

t (0.5) = ln2/K or 0.693/K