development of the dosage regimen Flashcards
onset of a drug affects the what?
the rate of drug absorption and distributing
what does the intensity of the drug action affect
the amount of drug that is absorped and distributed
the duration of a drug action affects what
rate of drug metabolism and elimination
what two things affect the rate of drug metabolism and elimination
duration of drug action and drug dosing interval
what is the bioavailability of a drug
this is the fraction of the administered drug that reaches the plasma in a chemically unchanged and biologically active form
what is the fraction of the administered drug that reaches the plasma in a chemically unchanged and biologically active form
the bioavailablilty of a drug
why does the first pass hepatic metabolism have an influence on the bioavailability of a drug
because when taken orally, the drug passes through the liver where part of it is metabolized thus making parts of the drug not available
why does plasma protien of albumin, glycoprotiens affect the bioavailability
because they bind to a drug making it not able to pass the biological membrane, affecting absorption of the drug
what administered drugs rarely demonstrate 100% bioavailability
oral
what is distribution
process by which a drug reversibly leaves the blood stream and enters body tissues
what is distribution affected by?
impacted by blood flow, solubility of a drug, organ size
why might blood flow impact bioavalibility
because if there is lack of blood flow, the drug cannot be distributed as quickly around the body
what is the apparent volume of distribution
this is the ratio of the amount of drug in the body to the drug concentration in the plasma
VD = AMOUNT OF DRUG IN BODY / PLASMA DRUG CONCENTRATION
this is the apparent volume of distribution
why should we care about the apparent volume of concentration of a drug
so we know how much drug is required to achieve a specified concentration of the drug in the plasma
what is the therapeutic concentration of a drug
for a drug to exert a certain effect, the concentration of the drug in the plasma must fall within the therapeutic concentration range of that drug
if the plasma concentration of the drug is out of its therapeutic range, what effect would this exert
cause adverse effects such as toxicity
if the plasma concentration fo a drug is below the therapeutic range what kind of effect would it exert
it would produce little - no effect
what is the loading dose
used to quickly achieve a high therapeutic plasma concentration of drug
what does [d]o mean
this is the top of the therapeutic range of a drug
what is Wd
this is the weight of drug administered to the pt
what is vD
this is the apparent volume of distribution
what is the t1/2 life of a drug
refers to the time required for the serum concentration to decrease by 50%
according to the plateau principle, when is drug equilibrium reached
after 4 half lives of the drug are passed
