New Deck Flashcards
factors that affect passive diffusion (esp of drugs)
molecular size ionization lipophilicity of non-ionized species size and structure of absorbing stuface blood flow CONCENTRATION
What are the two types of doses?
loading dose, maintenance dose
maintenance dose
if excretion changes needs to be altered, but not change occurs in the loading dose
volume of distribution
constant that relates dose and concentration Concentration = dose/volume of distribution therefore - dose = C * Vd
rate of excretion
clearance * concentration clearance (mL/min) is constant for most substances, if it changes for some reason then the maintenance must be altered
clearance
volume of drug that is permanently removed /min, proportional to the original concentration
first-order rate process
first order because the process of passive diffusion is first-order, depends totally on concentration differences across membranes first-order = double concentration/ double rate, something to the power of one.
half-lives
most of drug is excreted in 3-5 half-lives how long it takes to get into the body and out
steady state
rate in = rate out - want to get up to a fairly constant rate of a drug - takes 3-4 1/2 lives to get up to steady stage (imp to remember)
accumulation
- depends on rate of administration and clearnace - T1/2 - times it takes to
rapid drug effect
empty stomach