Pharmocokinetics Flashcards
Absorption is
Process by which the drug enters the systemic circulation
Is the passage of a drug from its site of administraiton into the plasma
Via – passive diffusion, diffusion through aqueous pores, carrier mediated transport or pinocytosis
Drugs need to be LIPID SOLUBLE
the fraction of an administered dose that reaches systemic circulation as the parent drug- definition of what
Bioavailability
fro oral r<1
Distribution is
process by which drug is transferred reversibly between plasma and tissues
which way of administration of drug means most goes from the blood to vessel rich tissues?
IV administration
what administration technique to the blood is taken up slowly oral or IV
oral
what administration technique is very much like eq
oral
in metabolism what is added to the drug to make the primary product
expose or add functional groups
oxidation reduction hydrolysis
volume of plasma in the vascular compartment cleared of drug per unit time by the processes of metabolism and excretion - defining
clearance
CL=
rate of elimination from the body/ drug concentration in plasma
mathematically clearance is the product of the first order elimination rate constant k and the apparent volume of distribution Vd
Cl=kxVd
difference between zero order and first order elimination
frist order elimination kinetics -elimination of a constant fraction per time sit of drug present in O. Elimination is proportional to the drug conc
zero order kinetics - elimination of a constant quantity per time unit of O
what does the therapeutic index =
dose resulting in toxicity/ dose giving therapeutic response
what does a high TI indicate
low risk of toxicity
when might harmful drug-drug interactions occur
with narrow TI drugs as small increase in plasma conc can cause toxic effects
Pharmacokinetics definition
- what the body does to the drug
