Therapeutic Drug Monitoring (TDM | F) Flashcards
What are the goals of TDM?
1) To ensure that a given drug dosage produces:
a. Maximal therapeutic benefit
b. Minimal toxic adverse effects
2) Must have an appropriate conc. at site of action that produces benefits
True or False
In relation w/ TDM, std dosages are derived from healthy population
True
In relation w/ TDM, only the free fraction of drugs can interact w/ site of action, resulting in what?
In a biologic response
What are the different routes of administration?
1) Injections
a. Circulation = IV (intravenous)
b. Muscles = IM (intramuscular)
c. Skin = SC (subcutaneous)
d. Epidermal
2) Inhaled
3) Absorbed through skin
4) Rectal
5) Oral
What is the most common route of administration?
Oral
What is pharmacokinetics?
It involves the dynamics associated w/ the movement of drugs across cell membranes
What are the biological events that are involved in pharmacokinetics?
1) Absorption
2) Distribution
3) Metabolism / Biotransformation
4) Excretion
What is the relationship present in pharmacokinetics?
Relationship of drug conc. to time
The process of pharmacokinetics assists in what?
In establishing or modifying a dosage regimen
What is absorption (as 1 of the biological events included in pharmacokinetics)?
It is the rate at w/c drug leaves the site of administration and the extent to w/c this happens
What are the different mechanisms of absorption (w/c is 1 of the biological events included in pharmacokinetics)?
1) Passive diffusion
2) Active transport
What is the principle of absorption (w/c is 1 of the biological events included in pharmacokinetics)?
Limiting factors
What is the route of administration for absorption (w/c is 1 of the biological events included in pharmacokinetics)?
Oral administration
Oral administration depends on what (in relation to absorption)?
1) Formulation of drug
- > liquid / pill
2) Intestinal motility
3) pH
4) Inflammation
5) Food
6) Presence of other drugs
7) Pt age
8) Pregnancy
9) Concurrent pathologic conditions
Where does metabolism (w/c is 1 of the biological events included in pharmacokinetics) occurs where?
In the liver
What is the principle of metabolism (w/c is 1 of the biological events included in pharmacokinetics)?
Biotransformation of the parent drug molecule into 1 or more metabolites
What are the metabolites (in relation w/ metabolism)?
1) H2O soluble
2) Easily excreted by kidney / liver
3) Pharmacologically active or inactive
The distribution (w/c is 1 of the biological events included in pharmacokinetics) depends on what?
1) Blood flow
2) Capillary permeability
a. pH gradients
b. lipid solubility of the drug
3) Binding of drugs to proteins / availability of free fractions
a. Free vs. bound drug
4) Tissue volume
What are the elimination routes (in relation w/ excretion w/c is 1 of the biological events included in pharmacokinetics)?
1) Hepatic metabolism
2) Renal filtration
3) Other
a. Skin
b. Lungs
c. Mammary glands
d. Salivary glands
In relation to elimination (w/c is related w/ excretion), fxnal changes in organs can affect what?
Elimination rate
Provide an ex of the principle of fxnal changes in organs w/c can affect elimination rate (in relation w/ elimination)
Hepatic disease w/ a loss of tissue result in slow rate of clearance w/ a longer half-life
What is elimination half-life (in relation w/ elimination)?
It is the time required to reduce the blood lvl conc. to one-half after equilibrium is obtained
In pharmacokinetics, how are most drugs given?
Most drugs are given on a scheduled basis (not as a single dosage)
-> oscillation between a max. (peak) and a min. (trough) of serum conc.
What is the principle of the goal of dosage regimens (in pharmacokinetics)?
Achieve troughs in therapeutic range and peaks that are non-toxic
