Principles of Pharmacology 2 Flashcards
EC50
the concentration of a drug or compound that is required to produce a half-maximal effect on a biological system.
when the EC50 of a drug is low, then the affinity is…………..
when the EC50 of a drug is high, then the affinity is………….
high
low
at what concentration does a drug with a high affinity need to be used to produce optimal effect
low concentrations
at what concentration does a drug with a low affinity need to be used to produce an optimal effect
high concentration
potency
relates to how big a dose you need to give to gain a particular effect in an intact animal
what dose is required when a drug is high in potency
a low dose
if the potency of a drug is low, then what dose of it is required to produce a response
a high dose
what does it mean if a drug has a high potency?
it means that the drug is effective at producing a specific biological or pharmacological effect at a relatively low dose or concentration
what was the original conception(thought) of the drug-receptor interaction
that the drug combines with the specific receptor to produce a drug-receptor complex. This DR complex gives a certain amount of response to the tissue, therefore when all receptors are occupied the maximum response is reached
intrinsic activity
It is a critical concept in pharmacology and drug development and is often used to categorize drugs or compounds based on their ability to elicit a response at a given receptor.
types of agonists
full agonist
partial agonist
full agonist
partial agonist
an agonist that produces the full or maximum response
an agonist that produces a partial response
100% receptor occupancy means 100% effect, true or false
FALSE
drug efficacy
refers to the ability of a drug to produce a desired therapeutic effect or beneficial outcome when administered under specific conditions.
what do efficacy and intrinsic activity have in common
they both give an idea of the overall maximum effect of the agonist
when can partial and full agonist log concentration curves be useful?
They aid in understanding and optimizing the effects of drugs, evaluating their therapeutic potential, and ensuring patient safety
what does the choice between using a partial or full agonist depend on
the specific clinical scenario, desired therapeutic effects, and potential risks and side effects.
the formula for calculating intrinsic activity
maximal response to test agonist/ maximal response to full agonist
intrinsic activity ranges between?
0-1
inverse agonists
a pharmacological compound that binds to the same receptor as an agonist (a molecule that activates the receptor) but produces the opposite effect
differences between inverse agonists and antagonists
Antagonists bind to receptors but do not have intrinsic activity; they block the binding of agonists without affecting basal receptor activity. In contrast, inverse agonists actively reduce the basal activity of the receptor.
antagonists
they are pharmacological compounds that bind to specific receptors or molecules in the body and block or inhibit their activation by agonists
what are the types of antagonists?
chemical
physiological
pharmacological
chemical antagonists
substances or compounds that act as antagonists by directly interfering with the function of a target molecule, typically without binding to a receptor.
do chemical antagonists depend on interactions with the agonist’s receptor
no
physiological antagonists
type of antagonism that occurs when two different physiological or pharmacological pathways produce opposing effects to regulate a specific physiological function or process
give an example of physiological antagonism
Vasodilation vs. Vasoconstriction
pharmacological antagonists
antagonists that combine with a receptor, do not produce a response but prevent the action of an agonist
what are the types of pharmacological antagonists
competitive-reversible
competitive-irreversible
non-competitive- reversible
non-competitive-irreversible
how can competitive antagonism be overcome
by giving a high enough concentration of agonist
non-competitive antagonists
they bind to a receptor at an allosteric site, thereby causing a conformational change in the receptor, which reduces it’s responsiveness to the agonist
how can irreversible antagonism be overcome?
can increasing the agonist concentration help overcome this?
by making new receptors through protein synthesis
no, it is useless in this case
features of irreversible antagonism
can prevent the binding of the agonist
it effectively removes affected receptors from the population
maximum response to the agonist is reduced
EC50 remains the same for the unaffected receptors
The binding of the antagonist does not alter the ability of the agonist to bind to “normal” receptors
Advantages of the sigmoidal shape of the log dose-response curve
A wide range of doses can be accommodated easily in the graph
Maximal response plateau is clearly defined
Central portion of the curve approximates to a straight line , allowing the collection of fewer data points to delineate the relationship accurately
drugs with high affinity have high potency, true or false
true
a drug with a low EC50 has a ……….. potency
high
efficacy is dependent on?
intrinsic activity
drug-receptor interactions
