Pharmacokinetics Flashcards
Define metabolism
irreversible transformation of parent compounds to into daughter compounds called metabolites
What are the four processes of PK
Absorption, distribution, metabolism, and excretion
Define absorption
movement of the drug from the suite of administration to the systemic circulation
define excretion
Excretion is the removal, of the substance from the body. The kidneys are the main organ that excretes water soluble substances, and the biliary system excretes drugs that are not reabsorbed from the intestine.
What is the only delivery route that does not require a drug be absorbed before it reaches the systemic circulation?
IV
What organ do the four processes take place in each step?
absorption- skin, mucous membranes, oral, IV
distribution- systemic circulation
metabolism- mainly liver
excretion- kidney primarily but also in the intestine, skin, and lungs
when are peak levels drawn?
15-30 min after the dose is completed
When are trough levels drawn
prior to administration of the next dose
Why is it important to know the half life of a drug?
To know how long the drug will continue to affect the target tissue
What does the Pharmaceutical phase of pharmacotherapeutics refer to?
what happens to the drug before it actual gets into the patient. It is the route or vehicle that the drug enters the body like tablets, ER, capsules, cream, etc
Why is a drugs volume of distribution important?
It determines the dose of a given drug form
If a drug likes to stay in the plasma, will it have a high or low volume of distribution, why?
A drug that mainly stays in the plasma will have a low VD because it is highly bound to plasma proteins
which drugs cross cell membranes more easily, lipophilic or hydrophilic substances?
lipophilic, it can cross the lipid layer in the wall of the intestine easier and move into the lipid bilayer.
AUC is the measure of what?
Area under the curve- it measures the drugs exposure of how much and how long drug stays in the body. (therapeutic concentration)
For how many half-lives does a drug generally remain in the body?
3-5
define distribution
dispersion of drug through various body fluids and tissues
What is the pharmaceutical phase?
the vehicle and route that the drug takes to reach the body (tab, enteric coated, ER, cream ointment, etc)
if a drug is lipophilic will be sparsely or widely distributed?
Widely
What is the Cmax and Cmin?
CMAX is the peak of maximum plasma concentration
CMIN is the trough of minimum plasma concentration of a drug
what does the AUC measure?
It measures the drugs exposure to the body and how much and how long the drug stays in the body
What are the major factors affecting t1/2?
volume of distribution and clearance of the drug
what is MEC?
minimal effective concentration
what is MTC
minimal toxic concentration
