kinetics 4 - 6.5 Flashcards
DRUG DISTRIBUTION
There are _____ (how many?) possibilities how the drug will distribute itself in our body
3
What Drug distribution
It will just distribute
evenly to the entire body compartment
when you administer 20 units, and you allow it to equilibrate into the compartments, there will be remaining 2 units in the blood when you check the blood. The presumption there is that the other 18 units went to other compartments.’ 20 units is the total amount in the body, over 2 units that are in the plasma.
Drug A - Does not bindto macromolecules, diffuses freely between 2compartments (Like 24 oras)
What Drug distribution
type of drug is that avidly binds to transport protein in the blood.
wherein if you administer 20 milligrams or 20
units and to check in plasma, there are 18 units in
plasma, you presume there are 2 units in the
peripheral tissues and the other compartments. It
depends whether this is good or bad.
Drug B - binds avidly to albumin in the blood,diffusion is much more limited. In each case,the amount of the drug in the body are the same but the apparent volumeof distribution are different
For example, if you are treating muscle
necrosis/meningitis, all drugs go to the blood;
which does not go to the target, which is the
brain; so it is not a good volume of distribution.
What Drug distribution
third type is the type of drug that would bind to the ghost areas that if you administer only 20 units then all your units would stay here and none in the blood
With this type of drug, you need to administer
200 units so that there will be some left after
saturating everywhere it goes before it reaches
the blood
Drug C - The third type is the type of drug that would rather go to the peripheral tissues; Because of this, out of the 200 units, only 2 are left in the blood
The volume of distribution is relatively high
Binding to tissues:
(increases/decreases) plasma concentration, (increases/decreases) apparent volume
decreases plasma conc.
increases apparent volume
Binding to plasmaproteins:
(increases/decreases) plasma concentration, (increases/decreases) apparent volume
increases plasma conc.
decreases apparent volume
When a drug is completely retained in the plasma compartment, Volume of distribution is _____ to the plasma volume
equal
Clearance Formula is
CL = rate of elimination of the drug / plasma drug conc.
Clearance unit is
volume per unit time (ml/min, L/h) or CL/body wt.
Clearance depends on the ff: (3)
○ Drug
○ Blood low
○ Condition of the organs of elimination
■ Extraction capability of the organ
■ Drug delivery to the organ
Rate of drug elimination is (indirectly/directly)
proportional to the concentration
Directly
is the time needed to
reduce the plasma concentration
by 50% of the initial drug
concentration.
Half-life
factor that predicts the
rate of elimination in relation to the drug
concentration (C):
Clearance
ANother formula of clearance
Cl = rate of elimination / Drug concentration (C)
Elimination of drugs from the body may involve
processes occurring in the _____ , ______, ______ and other organs.
kidney, the lung, the liver,
