Drug Elimination Flashcards
what is the principal organ for drug elimination?
kidneys
what happens to drug plasma concentration when rate of absorption > rate of elimination?
increases
what happens to drug plasma concentration when rate of absorption = rate of elimination?
peaks
what happens to drug plasma concentration when rate of absorption < rate of elimination?
decreases
what is clearance?
the volume of blood cleared of drug per unit time
what is CLr?
renal clearance
what is CLh?
hepatic clearance
what is CLo?
clearance by other elimination routes
what is CLt?
total clearance
why is clearance important?
helps determine the dosage rate needed to maintain a desired plasma drug concentration
how do you calculate CL?
rate of drug elimination/plasma drug concentration
what does first order kinetics refer to?
the rate of drug elimination increases as plasma drug concentration increases
what does zero order kinetics refer to?
when elimination mechanisms become saturated and reach Vmax
when does drug plasma concentration reach a steady state?
when rate of drug administration = rate of elimination
what is t1/2?
elimination half life
what does elimination half life determine?
the time required for plasma drug concentration to achieve steady state
what effect does ageing have on t1/2?
decreases
what effect does obesity have on t1/2?
increases
what effect does pathological fluid have on t1/2?
increases
what effect does cytochrome P450 have on t1/2?
induction = decreases inhibition = increases
what effect does cardiac failure have on t1/2?
increases
what effect does hepatic failure have on t1/2?
increases
what effect does renal failure have on t1/2?
increases
