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
What are the different drug grps?
1) Cardioactive
2) Antibiotics
3) Antiepileptic
4) Psychotherapeutic
5) Antiasthmatic
6) Immunosuppressive
7) Antineoplastic
8) Antihypertensive
What are the different drugs under the cardioactive drug grp?
1) Digoxin
2) Lidocaine
3) Quinidine
4) Procainamide
What are the actions of digoxin?
1) Used to treat congestive heart failure (CHF)
2) Inhibits Na and K transport within the heart
3) Allows for better cardiac muscle contraction and rhythm
What is the characteristic of digoxin?
It peaks draw at 2 hrs post dose
What are the actions of lidocaine?
1) It is used to treat premature ventricular contractions
2) It affects the timing of cardiac contraction
What is the characteristic of lidocaine?
It is a common dental anesthetic
What are the actions of quinidine?
1) It is used to treat cardiac arrhythmic problems
2) It inhibits Na and K channels
3) It prevents arrhythmias
4) It prevents atrial flutter
5) It prevents fibrillation
What are the actions of procainamide?
1) It is used to treat cardiac arrhythmic situations
2) It blocks Na channels
3) It affects cardiac muscle contraction
How is procainamide often measured?
It is often measured w/ N-Acetyl procainamide (NAPA)
What are the different drugs under antibiotics drug grp?
1) Aminoglycosides
2) Vancomycin
What are the actions of aminoglycosides?
1) It is used to treat infections w/ gram-(-) bacteria that are resistant to less toxic antibiotics
2) It inhibits protein synthesis of the microorganism
What are the exs of aminoglycosides?
1) Gentamicin
2) Tobramycin
3) Amikacin
4) Kanamycin
What are the actions of vancomycin?
1) It is used to treat infections w/ more resistant gram-(+) cocci and bacilli
2) It inhibits cell wall synthesis
What generation antiepileptics (AEDs) are mostly used to treat seizure disorders and epilepsy?
1st and 2nd
What are the exs of 1st generation AEDs?
1) Phenobarbital
- > Barbiturate Primidone its proform
2) Phenytoin
- > = Dilantin
3) Valproic acid
- > = Depakene
4) Carbamazepine
- > = Tegretol
What are the exs of 2nd generation AEDs?
1) Felbamate
2) Gabapentin
3) Levetiracetam
4) Oxcarbazpine
5) Tigabine
6) Topiramate
What are the drugs under the psychotherapeutic drug grp?
1) Lithium
2) Tricyclic antidepressants (TCAs)
3) Clozapine
What is the action of lithium, TCAs, and clozapine?
These are used to treat manic depression (bipolar disorder)
What are the drugs under the antiasthmatic drug grp?
1) Theophylline
2) Pulmicort
3) Theobromine
What is the action of drugs under the antiasthmatic drug grp?
These are used to treat neonatal breathing disorders or respiratory disorders (of adults or children)
What are the drugs under the immunosuppressive drug grp?
1) Cyclosporine
2) Tacrolimus (Prograf)
Why is the monitoring of the immunosuppressive drug grp impt?
To prevent organ transplant rejection (graft vs. host)
What is the action of the immunosuppressive drug grp?
These are used to treat autoimmune disease as well
What is the sx of choice for cyclosporine?
Whole blood
Why is whole blood the sx of choice for cyclosporine?
Since it sequesters in the RBC
What is the action of tacrolimus?
It prevents rejection of liver and kidney transplants
What is the drug under the antineoplastics drug grp?
Methotrexate
What is the action of methotrexate?
It inhibits DNA synthesis
What is the action of the antineoplastics drug grp?
It inhibits RNA / DNA synthesis of tumor cells (leading to cell death)
What are the actions of the antihypertensive drug grp?
1) It is used in treatment of high BP
2) It dilates blood vessels
What is the drug under the antihypertensive drug grp?
Sodium nitroprusside
What is the action of sodium nitroprusside?
It is used for short-term control of hypertension
What are the techniques for measurement of TDM?
1) Immunoassays
2) Gas chromatography
3) Liquid chromatography
4) Mass spectrometry
