potency, efficacy, and the therapeutic index Flashcards
pharmacokinetics
study of drug movement through the body aka absorption, distribution etc.
pharmacodynamics
study of how a drug changes the body
quantal effects
yes/no response, this when when we are trying to indicate whether or not a drug achieves a certain response e.g does this medication alleviate a headache
what is the ED50 median effective response
this is the dose required to produce a specific therapeutic response in 50% of patients
what is the ED50 response also referred to as
standard dose
what is the therapeutic index
this is the ratio of a drugs T50 to its ED50
what is the median lethal dose LD50
this is the amount of drug that would be lethal in 50% of test animals
median toxic dose TD50
this is the dose that will produce a given toxicity in 50% of patients
what is a therapeutic window
range based on the minimum effective therapeutic concentration and the minimum toxic concentration for a specific toxic effect
the bigger the therapeutic index..
the safer the drug
what makes a drug more safe
the therapeutic window
medications with a very small therapeutic window are considered what medications
high alert medications
what are graded effects
not yes or no, asks how much. e.g how much can this medication drop my pt blood pressure
phase 1 of graded effects
very little medications, very little effect
phase 2 of graded effects
there is now a relationship between the dose of the drug administered and the degree of client response
what phase has a linear relationship between amount of drug administered and degree of client response
phase 2
phase 3 of graded effects
when the plateau is reached. no therapeutic effects
potency
comparing doses of medications to respect how much drug is needed to produce a specific response
if a drug is highly potent, how much of the drug is needed fro a therapeutic response
not much
efficacy
the greater the efficacy the greater the capacity of the drug to exert its full biological effects
do we want a drug with a big efficacy or small
big
if three drugs are equally efficacious how should you choose
choose the one that is most cost efficient
rate of association
the rate at which a drug binds to a receptor
what is k-1
this is the rate at which a drug binds to a receptor and lets go
what kind fo drugs do we want when considering recpetor binding
we want drugs with a high affinity for drug binding
what does it mean when a drug has an high affinity
it means that it binds to a receptor quickly and dissociates slowly
what is a low affinity
it will have a low association and fast dissociation
low affinity is how potent
poorly potent
high affinity is how potent
very potent
agonist types
full, partial, inverse
antagonist types
reversible, competitive, non competitive, irreversible
agonists act as what
they act as a replacement for the hormone or a endogenous ligand or drug that is insufficient
full agonists
able to achieve the full biological effect at the endogenous ligand receptor
what kind of drug is identical to what the body would be producing on its own
full agonist
dexamethasone produces the same response as what
cortisol
partial agonist
will only achieve a fraction of the biological effect
the efficacy will always be what of partial agonist
lower efficacy than a full agonist
inverse agonist and intrinsic activity
when alone, they physically change the physiology of a cell
what kind of efficacy do inverse agonists have?
negative efficacy
when can we use a inverse agonists
when someone is nervous/anxious GABAa receptor stimulation making the person more relaxed
what agonists bind to a receptor and cause the receptor to be less than what it usually is
inverse
antagonists do what
they bind to the receptor site as the endogenous ligand, but do not produce a billogical repsonse
what efficacy do antagonists have
they dont have any, because they stop the drug
irreversible antagonists
cannot be reversed unless the cell is destroyed and replaced with a new one
competitive antagonism
competes for the same receptor binding site as the endogenous ligand
once the competitive antagonist is binded what happens
it blocks the endogenous ligand from binding
non-competitive antagonism
binds to a site other than the endogenous receptor
what does the competitive antagonist bind to
binds to the enzyme, changing the conformation of the receptor so the endogenous ligand cant bind
what antagonist changes the confirmation of the enzyme
non-competitive antagonist
examples of non-competitive antagonists
PCP, ketamine
what is the k-1 and kd of a irreversible antagonist
k-1 is equal to 0
KD is very low, affinity is very low
