Therapeutic Drug Markers Flashcards
The mechanism of action is defined as the biochemical or physical process that occurs at the ___ to produce the pharmacological effect.
site of action.
For drug administration, the parenteral route is defined as…
Outside the intestine (i.e., IV, IM, SQ, etc.).
Drug action is ___ mediated at the cellular membrane.
receptor.
For drug administration, GI absorption can include…
Rectal/suppository.
The rate of absorbance is classified by which two biochemical methods?
Passive diffusion and dietary transport mechanism.
Which GI changes can affect drug absorption?
GI motility, pH, inflammation, food, and other drugs.
Define first pass metabolism.
a drug gets metabolized at a specific location in the body that results in a reduced concentration of the active drug upon reaching its site of action or the systemic circulation.
Which drug type correlates with therapeutic and toxic physiological effects? (Bound or Free)
Free drug.
Which two factors effect the amount of free drug available?
(1) Serum protein level; (2) Competitive binding for the receptor on the transport protein.
What is the major site of metabolic clearance and biotransformation?
Liver.
Unmetabolized drugs are termed the ___ compound; metabolized products are termed ___.
parent; metabolites.
Define xenobiotic.
Exogenous substances (drugs) that are capable of entering the metabolic pathway.
Describe Phase I enzyme reactions.
Chemical structure modification produces reactive intermediates.
What is the enzyme responsible for Phase I Enzyme reactions?
Cytochrome P450.
Describe Phase II Enzyme reactions.
The drug becomes water soluble because of the conjugation of the functional group.
How does the depletion of conjugate groups effect Phase I & II enzyme reactions?
Can create a backup of Phase I reactive intermediates which may become toxic.
How are free form drugs and metabolites eliminated by renal clearance?
Glomerular filtration - renal secretion through the tubules.
The rate of drug clearance correlates with ___ clearance.
creatinine.
How will a decreased GFR effect serum half life and concentration?
It will cause it to increase.
An IV bolus of a drug is what type of elimination?
First-order.
Define half life.
Time required for the concentration to be decreased by one half.
Define the drug distribution rate.
How long it takes the drug to distribute throughout the body.
Define minimum effective concentration (MEC).
Lowest concentration of the drug in the blood that will produce the desired result.
Define minimum toxic concentration (MTC).
The lowest concentration of the drug in the body that will produce an adverse response.
Define the therapeutic index.
The ratio of MTC/MEC; varies from drug to drug and patient to patient.
Define the therapeutic window.
Range between MEC and MTC.
Define trough.
Lowest concentration of drug measured in the blood.
Define peak.
Highest concentration of the drug measured in the blood.
The following graph is indicative of what type of elimination?
First-order
What is the most important factor of TDM sample collection?
Timing; trough or peak.
What samples are collected for TDM testing?
Serum or heparin plasma.
Why should gel tubes be avoided for TDMs?
They absorb drugs and cause a false decrease.
