Kinetics 1-3 Flashcards
the measure of the
apparent space in the body available to
contain the drug
Volume of distribution:
the measure of the ability of the
body to eliminate the drug
Clearance
dose-concentration
pharmacokinetic
concentration-effect
pharmacodynamic
3 KINETIC HOMOGENEITY
Rate of input (absorption)
Rate of distribution to other tissues
Rate of elimination
is the function of three
pharmacokinetic rates
Plasma concentration
represents the absorption whether it
is administered on any route
Rate of Input
to the peripheral
tissues of target organs
Rate of distribution to other tissues
which is the function of the
metabolizing organs (liver) which is excretory and
so is your kidneys.
Rate of elimination
water-soluble drug is
excreted through the _____.
Urine
. Lipid-soluble drug, since
it is insoluble in water is excreted via the______.
the bile (biliary
excretion).
DISTRIBUTION: Deliver to interstitial and intracellular fluids. Initial organ are _____
Liver, Kidney, Brain (Slower in muscle, viscera, fat and skin)
PLASMA BINDING PROTEINS: Acidic drugs binds to ______
Albumin
PLASMA BINDING PROTEINS: Basic drugs binds to ______
alpha 1 acid glycoprotein
T/F: More highly protein bound drug will displace the
less protein bound drug
○ Eg, A- 90% protein bound
○ B- 50% protein bound
○ A will displace B
○ More unbound drug “B” to act on the
receptor site
True
When plasma proteins are lower
than normal, total drug concentrations will be ______higher or lower
but unbound concentrations will not be affected.
Lower
assumed the patient is obese,
drugs do not readily penetrate fat (e.g ______)
Gentamicin, Digoxin, Tacrolimus, Gemcitabine
T/F: EFFECTIVE DRUG CONCENTRATION - Unique for a particular drug in a particular
patient
We based this on the normal or the average that is
seen on a population
True
2 important parameters (known absorption):
○ 1. VOLUME OF DISTRIBUTION (Vd)
○ 2. CLEARANCE (CL)
relates the amount of drug in the body to the concentration of drug in blood or plasma:
Volume of distribution (V)
Formula of Volume of distribution (V)
V = Amount of drug in body / C
volume of distribution may be defined with
respect to ____, ____, _____ (unbound drug), depending on the concentration used in the
equation above C = Cb, Cp, or Cc
blood, plasma, or water
high volumes of distribution have ____ conc. in extravascular tissue than in the vascular compartment
ie, they are not homogeneously distributed
higher
Drugs that are completely retained within the
vascular compartment, would have a _______ (minimum/maximum) possible volume of distribution equal to the plasma component in which they are distributed
minimum
Physical volumes of some body compartments
Compartment: Total body water r (0.6 L/kg1)
Small water-soluble molecules: eg, ethanol
Physical volumes of some body compartments
Compartment: Extracellular water r (0.2 L/kg)
Large water-soluble molecules: eg, gentamicin
Physical volumes of some body compartments
Compartment: Plasma (0.04 L/kg)
large protein molecules: eg,
antibodies
Physical volumes of some body compartments
Compartment: Bone (0.07 L/kg)
certain ions: eg, lead;
fluoride
Physical volumes of some body compartments
Compartment: Fat (0.2 - 0.35 L/kg)
highly lipid-soluble
molecules: eg, diazepam
ANother formula for Volume of distributioon
Vd = amount of drug in the body/plasma drug conc.
Unit for Vd
Liters or Vd/kg
apparent space in the body available to
contain the drug
Volume of Distribution
t/f: our body is a compartment of water, divided by the
lipid barriers
70 kilograms is the average. So, our body is about 70
- 80% water, depending on our muscularity
True
More Muscular, ____ (less/more) water
More
More adipose tissue, _____(more/less) fluid percentage)
less
