drug elimination

Question 1

elimination

Answer 1

irreversible loss of drug by excretion and/or metabolism

Question 2

excretion

Answer 2

irreversible loss of chemically unchanged drug.
- mainly via kidneys
- also: bile, sweat, saliva, air, milk

Question 3

metabolism

Answer 3

conversion of the drug into a different chemical species (biotransformation)
- mainly by liver
- also: lungs, gi wall, blood, skin, kidney

Question 4

what can drug elimination help you understand?

Answer 4

• find drug conc after taking medicine
• find how liver disease affects drug conc
• find interactions between drug and drugs, drugs and food, herbal products
• find variability in drug therapy in terms of age + genetics

Question 5

what is clearance (Cl) ?

Answer 5

elimination process for each drug is describing and quantified by its clearance

Question 6

define clearance

Answer 6

• the proportionality factor that relates the elimination rate of a drug with the drug concentration in blood (plasma)
• elimination rate of drug = clearance x Cdrug (mass/time) = (volume/time) x (mass/volume)
• volume of fluid that is completely cleared of drug per unit time

Question 7

units for clearance

Answer 7

volume/time (mL/min or L/h)

Question 8

what does Cldrug = 15mL/min mean?

Answer 8

15mL of plasma are cleared of drug every minute