Pharmacokinetics Flashcards
how to calculate the bioavailability?
area under curve for any other type of admin/area under for IV
what two things affect the bioavailability of an oral drug?
absorption in GI and first pass through liver
what part of drug can be cleared by the renal system?
only the unbound drug in the plasma
if your Vd is high…what are plasma levels of the drug?
low
if you Vd is low…what are plasma levels of the drug?
high
what is the equation for volume of distribution?
dose (mg)/plasma concentration (mg/L)
what is the equation for renal clearance of a drug?
UV/P for the drug
what is the equation for a drugs half life?
0.7 times Vd/clearance
as Vd increases…how does the half life change?
increases
what is the elimination rate constant?
Ke
how do you calculate the elimination rate constant (Ke)?
Vd/clearance
how do you use Ke to calculate the half life?
0.7/Ke=T1/2
how many half lives does it take to reach the steady state of a drug no matter the drug?
4-5 half lives
what is the equation for a drug with bioavailability of 100% for maintenance dose? what about with bioavailability less than 100%?
Plasma conc times clearance
or
plasma conc times clearance/bioavailability
if you know the maintenance dose of a drug..but you cannot give that amount due to tablets not being made in that mg…how do you calculate the maintenance dose?
plasma conc times clearance timea Tau
divided by
bioavailability
