Kinetics and Dynamics Flashcards
Describe drugs that CAN be easily absorbed through the GI tract.
Small molecules
Non-ionized, or non-charged, drugs
Lipophilic drugs
Acid drug mixed with an acid or base with base
Describe drugs that CANNOT be easily absorbed through the GI tract.
Large molecules
Ionized, or charged, drugs
hydrophilic drugs
Acid drug mixed with a base
What kinds of drugs easily cross the blood-brain and the placenta barriers?
Lipophilic because both barriers are mostly fat
Differentiate enteral drug administration from parenteral drug administration.
enteral: through GI tract
parenteral: outside GI tract (IV, IM, SC, etc.)
Where does most absorption of PO drugs occur?
small intestine
Define bioavailability.
Percent of drug dose that reaches the blood
What is meant if a drug is in a “depot” form?
Injected drug formulated to be slow release
Differentiate high volume of distribution from low.
High: drug goes everywhere in the body
Low: drug stays where you put it
What happens to a drug that binds to plasma protein?
The drug is inactive
What happens when 2 drugs that bind to plasma proteins are administered at the same time?
They compete such that one drug will not be as bound and thus, will be more pharm active than normal.
How are lipophilic and hydrophilic drugs eliminated?
Lipophilic by liver, hydrophilic by kidneys
How many half-lives does it take for a drug to be completely eliminated?
5 - 6
Define steady state relative to pharmacokinetics.
When absorption = metabolism/elimination
What is the role of CP450 in pharmacokinetics?
Family of pac-man like enzymes that chew up drugs in the liver.
What is the result of a drug that induces CP450? Inhibits?
Induce: Need higher dose b/c more drug chewed up
Inhibit: Need lower dose b/c less drug chewed up
