Dose Curves Flashcards
What is the dose response function
expresses the relationship between the dose administered and the response observed
How are does response functions determined
groups of individuals are administered a different amount of a drug in question and the response is measured; the test groups are compared to a control group given a placebo
what is a placebo
an inactive drug looks like a medication but is not
what is the placebo effect
attributed to psychological factors; expectations of drug effects and prior experiences
what is a double blind procedure
control measure for bias; neither the subject or researcher knows whether the substance given is the medication or placebo
What is a dose response curve
graph comparing the size of response to the amount of drug
x-axis: dose of drug
y-axis: effect of the drug
what is the difference between dose and concentration
concentration is the amount of molecule of interest in its vehicle
Dose refers to the amount of drug administered to a person
what are the components of a dose response
1) Dose-plasma concentration relationship
2) Plasma concentration-response relationship
what are the advantages of plotting a dose response curve on a log scale
1) full range of doses can be observed
2) easier to illustrate the effects/interactions of agonists and antagonists
What is Kd?
ratio of drug receptor dissociation
[drug][receptor] / [drug-receptor complex]
What does it mean if a drug has a high Kd
weak interaction, low receptor affinity
what does it mean if a drug has a low Kd
strong interaction, high receptor affinity
What happens as the concentration of a free drug increases in terms of Kd
the percentage of bound receptors increases
What is Emax
maximal observed effect of a dose of a drug
how do you calculate E?
E= Emax * [D} / Kd + [D}
what is a graded dose response curve
measured in a single biologic unit
continuous scale (increased dose = increased effect)
relates dose to intensity of effect
what is a quantal dose curve
population studies
all or none pharmacologic effect (did drug work? yes or no)
relates dose to frequency of effect
what is the slope factor of a dose response curve
increase of slope illustrates how much change in effect a little increase of dosage will have
what is a curvilinear or biphasic function of a dose curve
increasing doses are associated with increasing responses and then the effect decreases
what is the therapeutic window
the drug doses in which a therapeutic response is obtained
what are the characteristics of drugs that can be derived from dose response curves
threshold dose
maximal response
what is the threshold dose
the smallest dose that produces a measurable response
what is the maximal response
greatest degree of a given response that can be achieved with that drug
what is the ED50 of a drug
effective dose for half of the subjects tested /
the dose that produces 50% of max effect
