Flashcards in Intro To Pharmacodynamics Deck (21):
When you plot drug dose arithmetically on the X-axis vs. drug effect on the y-axis you typically get what is called a ____________ curve
It is more common for a concentration-efffect curve to be presented by graphing the logarithm of the drug dose vs. the response in which case you get a _____________ curve
What goes on the X and Y axis of a logarithmic dose response curve?
X-axis = log drug dose
Y-axis = % max response
What goes on the X and Y axis of an arithmetical dose response curve?
X-axis = drug dose
Y-axis = response
The maximal effect that can be produced by the drug
AKA effective dose 50
This is the dose of drug that produces 50% of its maximal effect
What is a graded response on a dose response curve?
- answers the question how much?
- magnitude of a response varies continuously
- typically represents the mean value within a population or a single subject
Which of the following processes is studied by pharmacodynamics?
A) metabolis of the drug in the liver
B) excretion of the drug with urine
C) relaxation of bronchial SM by a drug
D) absorption of the drug fro the site of administration
C) Relaxation of bronchial SM by a drug
What is a quintal response?
- all or none, yes or no, binary responses
- answers the questions does the response occur or not? In how many?
- requires a pre-defined response (ex. Death, falling asleep, 10% reduction in BP)
- used to examine the frequency of a response within a large population
What is the therapeutic index?
**The higher the TI the safer the drug**
What is the therapeutic window?
The range of doses of a drug or of its concentration in a bodily system that provides for the safe and effective therapy
Differentiate between cumulative and non-cumulative quintal dose response curves
Non-cumulative = number or % of individuals responding at a dose of a drug and only at that dose -> bell shaped curve
Cumulative = number or % of individuals responding at a dose of a drug and at all doses lower than that dose -> sigmoidal curve
How do you differentiate between whether or not a dose response curve is quantal or graded?
You look at the Y-axis!
Quantal = Y axis with population response or fraction
Graded = effect such as BP or something
Cholestyramine is a bile acid-binding resin that is used for thetreatment of hypercholestrolemia. It absorbs aspirin, preventing its absorption in GI tract and antagonizing its effects. Cholestyramine is an example of:
A)pharmacologic competitive antagonist
B) physiologic antagonist
C) chemical antagonist
D) pharmacologic non-competitive antagonist
E) pharmacologic allosteric antagonist
C) Chemical antagonist
A property of a drug determined by its affinities at various binding sites
- measured by comparing affinities of a drug to different receptors
- a more selective drug would affect fewer targets over a specific concentration range (therapeutic range)
T/F: Antagonists do not have intrinsic activity but agonists do
Explain pharmacologic antagonism
Action at the same receptor as endogenous ligands or agonist drugs
Explain chemical antagonism
When chemical antagonist makes the other drug unavailable
Explain physiologic antagonism
Occurs between endogenous pathways regulated by different receptors
A physician considers 2 medications, Drug A & B. Drug A is a partial agonist at a receptor. Drug B is a full agonist at the same receptor. Based on this info, which of the following is true regarding drugs A & B?
A. Drug A has a lower Kd than Drug B
A. Drug A has a lower Emax than Drug B
C. Drug A is less potent than Drug B
D. Drug A has a lower ED50 than Drug B
E. Drug A is less safe than Drug B
B. Drug A has a lower Emax than Drug B