Pharmacodynamic therapy defined

S Dose levels in vivo It is necessary to define the dose-response relationship of any adverse effects observed. The onset and duration of effects should be measured. Because there are differences in sensitivity between species, the doses chosen need to exceed those used for therapy. The ICH guideline states that the highest dose tested should be a dose that produces moderate adverse effects, for example, dose-limiting pharmacodynamic effects or other toxicities. Such effects should not be so severe that they confoimd the interpretation of the results being sought. Safety pharmacology studies... 

Different subpopulations may react differently to drugs, due to a variety of reasons affecting metabolism. However, differences are not always clearly defined. Factors that could influence patient susceptibility include multiple drug therapies, multiple disorders and severity of disease, types of drugs prescribed, altered pharmacokinetics, altered pharmacodynamics, and the age of the population treated (Nolan and O Malley 1988). 

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