lecture 4 Flashcards
the study of the effect of the body on a given drug
- pharmacokinetics
the concentration is measured in the _____ of the blood
- plasma
the concentration of first order elimination is plotted as
- log of serum concentration vs. time
first order kinetics
- a constant fraction of the drug is removed per unit time
zero order kinetics
- a constant amount of drug is removed per unit time, regardless of the concentration of the drug
an example of a zero order drug
- ethanol
alpha phase of elimination
- distribution
beta phase of elimination
- elimination
the time it takes for the concentration in plasma to decrease by half
- pharmokinetic half-life
relationship between elimination constant and half life
- 0.693 = Ke * T1/2
value which enables to predict how much drug must be given to obtain a specific plasma concentration of drug
- volume of distribution
volume of distribution
- plasma conc (at time=0) = amount given/apparent volume of distribution
volume of fluid which is cleared of the drug in unit time
- clearance
clearance
- Cl = Ke(Vd)
It take _____ for a drug to be 99% removed
- 5-6 half lives
It takes _____ to reach 99% of the final concentration when giving repeated doses
- 5-6 half lives
at equilibrium, steady state ____
- the rate of administration = the rate of elimination
equilibrium base equation
- (dose/interval) = ke (amount in body at steady state)
equilibrium final equation
- ((1.44 * T1/2 * dose)/interval) = amount of drug in the body at steady state
the initial dose which will achieve the desired steady state concentration immediately
loading dose
loading dose
concentration at equilibrium * Vd = loading dose
