Pharmacokinetic Phase Flashcards
PHARMACOKINETIC PHASE
What are the 4 processes of drug movement to achieve drug action?
○ Absorption
○ Distribution
○ Metabolism / Biotransformation
○ Excretion
ABSORPTION
Where does this happen?
Absorption happens in the small intestine bc of the action of
the mucosal villi.
Movement of drug particles from GIT to body cells, by?
Passive and Active Absporption
Passive Absorption
by principle of diffusion,
area of higher cont to the area of lesser cont.
Readily pumapasok yung cell
Active Absorption
hindi agad agad pumapasok
yung gamot inside the cell. It needs a carrier
(enzyme or protein) so the drug in the blood can
pass through
Pinocytosis
the cell will engulf the drug.
Drugs that are lipid-soluble and non-ionized (not
charged) are?
Drugs that are lipid-soluble and non-ionized (not
charged) – are absorbed faster in the GIT than water-soluble
and ionized drugs
Cell membranes are?
Cell membranes are lipid-soluble kaya kung
ganun din yung gamot, very easy siya
makakapasok ng cell by passive absorption
If drug is water-soluble
If drug is water-soluble, mahirap siya
makapasok. It passes thru a carrier (active
absorption).
Water-soluble and Ionized Drugs undergo what kind of absorption?
Active absorption
First-pass Effect
give examples
First-pass Effect – is a process where some oral drug
passes to the liver first.
Examples are: Morphine and Warfarin
HIGH first-pass
- When a drug has a very high first-pass, they are not recommended to have an oral form.
- Sometimes drugs with high first-pass have around 20-40% bioavailability lang. So when it reaches the systemic circulation, 20-40% nalang yung natira from the original dose.
Examples of high first-pass drug
Lidocaine and some nitroglycerines.
Bioavailability
Bioavailability – is the percentage of administered drug
dose that reaches systemic circulation
Oral drugs’ bioavailability is?
Oral drugs’ bioavailability is ALWAYS LESS
than 100%, esp if it has a high first-pass.
Drugs that have 100% bioavailability are drugs
that are given via?
IV ROUTE (derecho bloodstream).
DISTRIBUTION
Process by which the drug becomes available to body fluids
and body tissues.
Distribution is influenced by?
Protein-binding
Blood flow
Body tissue affinity
Protein-binding percentages:
Highly protein bound
Moderately Highly protein bound
Moderately protein bound
Low protein bound
- Highly protein bound > 89%
- Moderately highly protein bound 61% - 89%
- Moderately protein bound 30% - 60%
- Low protein bound < 30%
Why do he have to be cautious when giving highly protein bound drugs?
Be cautious when giving highly protein-bound
drugs because giving them together at the
same time can cause an increase in the
free/active drug in the bloodstream causing
overdose; The elderly and malnourished
people has less protein, meaning if given a
highly protein bound drug— there might be an
increase in a free drug
Free drugs
are active drugs that are not bound to protein
and can cause a pharmacological response
METABOLISM OR BIOTRANSFORMATION
The chemical activity of our body when we take a drug.
Half-life of a Drug
s the time it takes for one half of the drug
concentration to be eliminated.
steady state of serum concentration
dealing with the predictive, therapeutic effect of the drug
