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The dose–response relationship, or exposure–response relationship, describes the magnitude of the response of an organism, as a function of exposure (or doses) to a stimulus or stressor (usually a chemical) after a certain exposure time. [1] Dose–response relationships can be described by dose–response curves. This is explained further ...
The EC 50 of a quantal dose response curve represents the concentration of a compound where 50% of the population exhibit a response, [5] after a specified exposure duration. For clarification, a graded dose response curve shows the graded effect of the drug (y axis) over the dose of the drug (x axis) in one or an average of subjects.
Stochastic health effects are those that occur by chance, and whose probability is proportional to the dose, but whose severity is independent of the dose. [3] The LNT model assumes there is no lower threshold at which stochastic effects start, and assumes a linear relationship between dose and the stochastic health risk.
The study shows a linear dose response for all solid tumors. [6] This means the relationship between dose and human body response is a straight line. [6] To see an example, look at the graph titled "Linear graph." Linear dose response also means that the rate of change of human body response is the same at any dose. [7]
PK/PD relationships can be described by simple equations such as linear model, Emax model or sigmoid Emax model. [5] However, if a delay is observed between the drug administration and the drug effect, a temporal dissociation needs to be taken into account and more complex models exist: [ 6 ] [ 7 ]
A trio of dose response curves A distinction should be made between quantification of drugs binding to receptors and drugs producing responses. There may not necessarily be a linear relationship between the two values.
The therapeutic ratio in radiotherapy for cancer treatment is determined by the maximum radiation dose for killing cancer cells and the minimum radiation dose causing acute or late morbidity in cells of normal tissues. [13] Both of these parameters have sigmoidal dose–response curves. Thus, a favorable outcome in dose–response for tumor ...
This refers to clinical pharmacodynamic knowledge describing dose-concentration-response relationships among treated patients. If the observed concentration is plausible but far from the suitable level, determine how to adjust the dosage to drive the concentration curve close to target.