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50 Cards in this Set
- Front
- Back
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what does pharmacokinetics describe
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mathematically describes rate of absorption (ie bioavailability), distribution, and elimination. it also describes drug regimens.
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what is plasma concentration a good reflection of
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what is in tissue, what is excreted, etc
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what does pharmacokinetics describe
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mathematically describes rate of absorption (ie bioavailability), distribution, and elimination. it also describes drug regimens.
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what does pharmacokinetics describe
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mathematically describes rate of absorption (ie bioavailability), distribution, and elimination. it also describes drug regimens.
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what does a arithmetic first order rate graph look like.
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conc on y-axis, time course on x axis. curved, asymptotic, exponential decay
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what is plasma concentration a good reflection of
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what is in tissue, what is excreted, etc
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what does a semilog first order rate graph look like.
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conc on y-axis, time course on x axis. straight line
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what is ke
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the elimination constant. it is negative slope of the semilog graph. slope = - ke
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what is plasma concentration a good reflection of
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what is in tissue, what is excreted, etc
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what does a arithmetic first order rate graph look like.
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conc on y-axis, time course on x axis. curved, asymptotic, exponential decay
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how do you figure out ke
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calculate half life from the elimination log graph and then relate it to elimination rate constant. t (1/2) = -0.693/ke
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what is the equation for rate of elimination for a first order eliminationkinetic drug
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dC/dt = -keC. rate of elimination is not constant b/c it depends on drug concentration.
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what does a semilog first order rate graph look like.
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conc on y-axis, time course on x axis. straight line
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what is the half-life equation
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t (1/2) = -0.693/ke. half-life is inversely proportional to the elimination rate constant
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what does a arithmetic first order rate graph look like.
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conc on y-axis, time course on x axis. curved, asymptotic, exponential decay
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what is ke
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the elimination constant. it is negative slope of the semilog graph. slope = - ke
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what does a semilog first order rate graph look like.
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conc on y-axis, time course on x axis. straight line
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how do you figure out half-life
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calculate half life from the elimination log graph
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how do you figure out ke
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calculate half life from the elimination log graph and then relate it to elimination rate constant. t (1/2) = -0.693/ke
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what is ke
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the elimination constant. it is negative slope of the semilog graph. slope = - ke
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if a drug has a half-life of eight hours and you want to give the drug every eight hours to achieve a maximum cumulative amount of 40 mg, what dose should you use
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20 mg. drugs which accumulate in the body will accumulate to 2 times the amount (or concentration) achieved with a single dose when given at intervals equal to their half-life
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what is the equation for rate of elimination for a first order eliminationkinetic drug
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dC/dt = -keC. rate of elimination is not constant b/c it depends on drug concentration.
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how do you figure out ke
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calculate half life from the elimination log graph and then relate it to elimination rate constant. t (1/2) = -0.693/ke
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what is the half-life equation
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t (1/2) = -0.693/ke. half-life is inversely proportional to the elimination rate constant
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what is the equation for rate of elimination for a first order eliminationkinetic drug
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dC/dt = -keC. rate of elimination is not constant b/c it depends on drug concentration.
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how do you figure out half-life
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calculate half life from the elimination log graph
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if a drug has a half-life of eight hours and you want to give the drug every eight hours to achieve a maximum cumulative amount of 40 mg, what dose should you use
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20 mg. drugs which accumulate in the body will accumulate to 2 times the amount (or concentration) achieved with a single dose when given at intervals equal to their half-life
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what is the half-life equation
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t (1/2) = -0.693/ke. half-life is inversely proportional to the elimination rate constant
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how do you figure out half-life
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calculate half life from the elimination log graph
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if a drug has a half-life of eight hours and you want to give the drug every eight hours to achieve a maximum cumulative amount of 40 mg, what dose should you use
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20 mg. drugs which accumulate in the body will accumulate to 2 times the amount (or concentration) achieved with a single dose when given at intervals equal to their half-life
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what is bioavailability
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F. math term for absorption.
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how do you measure bioavailability
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F = AUC/AUCiv;
if doses are different multiply F by dose IV/dose oral |
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what is the F for drugs given IV
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F = 1
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what drugs have particularly poor absorption in the GI tract
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poorly water soluble drugs
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which population are bioavailability drugs usually made with
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young people subjects but older people don't absorb drugs that well
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what is Kd
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constant for distribution.
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which drugs do you use a one compartment model for
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log graph: straight plasma concentration graph over time. drugs that immediately distribute thruout the body. these drugs have no distinct distribution phase
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which drugs don't use a one compartment model
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log graph. drugs that distribute very slowly have a distinct (nonlinear) distribution phase followed by a straight line. you have to use a 2 compartment model for these.
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what is volume of distribution
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apparent volume in which a drug appears to be dissolved. measures how much drug is taken up by tissues out of the plasma
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what is the volume of distribution equation
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Vd = Q/C. Q = dose for IV. F = bioavailability for oral.
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how do you calculate volume of distribution from graphs
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Vd = dose/Cp(o). you have to extrapolate the dose from time zero using a log graph.
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what two types of elimination are there
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first order and zero order.
arithmetic: curve, straight log: straight, curve |
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what type of elimination are zero order
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carrier mediated elimination only when carriers are saturated. rate of elimination is constant and independent of drug concentration.
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elimination rates for first order vs zero order elimination
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not constant (ie rate = -keC) vs constant (ie rate = delta Cp/ delta t)
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what happens to zero order elimination half-life since rate of elimination is constant
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there is no halflife
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what is drug excretion and what is drug clearance
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excretion: movement of drug from tissues and blood to external environment
clearance: plasma volume cleared of drug per time period. |
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example drug clearance problem: time zero: plasma [c] is 10 mg/mL. time 1 hr: plasma [c] is 5 mg/mL. plasma volume is 3 L
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clearance = fraction of drug cleared/unit time x plasma volume
OR Cl = Ke x Vd |
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what organs do clearance
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Cl = Clrenal + Clliver + Clother
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what is the plateau principle
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on steady administration of a drug, plasma concentration will rise fast at first then more slowly and reach a plateau (ss concentration). this only happens for first order drugs
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why does the plateau principle only work for first order elimination drugs
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you can't get a ss [c] because the plateau is reached when rate of drug in = rate out. and this doesn't work for zero-order elimination.
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