Pharmacokinetics Flashcards
What is Clearance?
It is the irreversible elimination of a drug from systemic circulation.
It is “volume of blood cleared of per unit time”
It is the constant relating the concentration of plasma to the elimination rate.
Cl= Elimination rate/plasma concentration
What is Elimination?
When is it considered complete?
It is the
a) excretion of a drug unchanged. This can be in the form of urine, sweat, feces etc.
b) the metabolism of a drug to another drug by the liver or other organs.
It is considered complete when all the parent drug has been excreted or metabolised (ie even if metabolites are still in the body, if the parent drug has been converted it doesn’t count)
What is the extraction ratio?
What is it’s formula?
It is the ratio of drug clearance to blood flow
It is 1-(concentration out/concentration in)
Maintenance Dose Rate formula
DR=Cl x [plasma]
