lOMoARcPSD|11700591
Study guide exam one units 1-3
Unit one Week one pharmacology
Pharmacokinetics and Pharmacodynamics
Week one notes
Pharmacodynamics- what the drug does to the body
What effect does the drug have on the person you are giving it to
Pharmacokinetics- Pharmaco (drug) kinetics (movement)
- What does the body do to the drug
Pharmacokinetics has 4 phase
AD-ME – Absorption, distribution, metabolism, excretion
A-Absorption
Drug moves from site of absorption (small intestine) into the
bloodstream
Bioavailability – how much of the drug reaches the blood
stream
Factors affecting absorption
1.Circulation
- Poor blood flow to the GI tract and you taking oral med will lead
to a decrease in the rate of absorption
- Happens in pt. in shock or vasoconstricting drugs
2. Pain, stress, exercise
- Blood gets shunted away from the gut.
, lOMoARcPSD|11700591
Food / decrease in GI motility
- delays absorption
PH
- most drugs needs a low PH for absorption acids breaks things
down into a more absorbable form
Route
- route of administration affects absorption /bioavailability
- iv = 100 percent bioavailability
80 % of drugs are taken orally
- in order for drug to be used (absorbed) has to go through a process
called disintegration – (broken down into smaller particles.) then it
has to dissolve (dissolution)
- enteric coated tabs slower disintegration
- enteric coated tabs need an alkaline environment for absorption
first pass effect
- affects absorption /bioavailability of oral medications
- example of the 1st pass effect is PO vs IV Tylenol
- drug travels to the liver via the portal vein and gets broken down
D- distribution
- Describes delivery of the blood from the blood stream to the tissue
(target cells)
Factors affecting distribution
, lOMoARcPSD|11700591
1.Protein binding (blood interaction with plasma proteins)
- If a drug is tightly bound to proteins it won’t be able to reach target
cells.
- Tight binding prevents drug delivery (distribution)
- Unbound portion = free drug which is what reaches the cell
- Conversely- lower plasma protein levels = more free drug,
however to much free drug = toxicity
Anatomical barriers
- Blood brain barrier
- Placental barrier
- Benadryl 1st generation crosses the blood brain barrier which
causes sleepiness
- Claritin 2nd generation does not
M- metabolism
- Describes the process of blood inactivation. Drug being broken
down before its eliminated broken down in the liver.
Factors affecting
1.Half life
- Amt of time it takes for the amt of drug to be reduced by half
Ex.
Long half lives
- Digoxin – half life is 36 hr
Study guide exam one units 1-3
Unit one Week one pharmacology
Pharmacokinetics and Pharmacodynamics
Week one notes
Pharmacodynamics- what the drug does to the body
What effect does the drug have on the person you are giving it to
Pharmacokinetics- Pharmaco (drug) kinetics (movement)
- What does the body do to the drug
Pharmacokinetics has 4 phase
AD-ME – Absorption, distribution, metabolism, excretion
A-Absorption
Drug moves from site of absorption (small intestine) into the
bloodstream
Bioavailability – how much of the drug reaches the blood
stream
Factors affecting absorption
1.Circulation
- Poor blood flow to the GI tract and you taking oral med will lead
to a decrease in the rate of absorption
- Happens in pt. in shock or vasoconstricting drugs
2. Pain, stress, exercise
- Blood gets shunted away from the gut.
, lOMoARcPSD|11700591
Food / decrease in GI motility
- delays absorption
PH
- most drugs needs a low PH for absorption acids breaks things
down into a more absorbable form
Route
- route of administration affects absorption /bioavailability
- iv = 100 percent bioavailability
80 % of drugs are taken orally
- in order for drug to be used (absorbed) has to go through a process
called disintegration – (broken down into smaller particles.) then it
has to dissolve (dissolution)
- enteric coated tabs slower disintegration
- enteric coated tabs need an alkaline environment for absorption
first pass effect
- affects absorption /bioavailability of oral medications
- example of the 1st pass effect is PO vs IV Tylenol
- drug travels to the liver via the portal vein and gets broken down
D- distribution
- Describes delivery of the blood from the blood stream to the tissue
(target cells)
Factors affecting distribution
, lOMoARcPSD|11700591
1.Protein binding (blood interaction with plasma proteins)
- If a drug is tightly bound to proteins it won’t be able to reach target
cells.
- Tight binding prevents drug delivery (distribution)
- Unbound portion = free drug which is what reaches the cell
- Conversely- lower plasma protein levels = more free drug,
however to much free drug = toxicity
Anatomical barriers
- Blood brain barrier
- Placental barrier
- Benadryl 1st generation crosses the blood brain barrier which
causes sleepiness
- Claritin 2nd generation does not
M- metabolism
- Describes the process of blood inactivation. Drug being broken
down before its eliminated broken down in the liver.
Factors affecting
1.Half life
- Amt of time it takes for the amt of drug to be reduced by half
Ex.
Long half lives
- Digoxin – half life is 36 hr
