Some keys fit so perfectly that they don't activate a receptor and they block other keys from gaining access, some keys 'stretch' the receptor and cause the neuron to fire. All this is well and good. However, the potential impact of a specific drug, that is revealed through an analysis such as what we have above, becomes a reality when substances are taken in particular ways by particular people living and interacting in particular places at particular times. Quality control Identity issue again Impact potency of a particular sample, and therefore dose . How much is needed of a particular drug sample Dose Properties of drug are only a potential until a specific dose is ingested There are levels at which any drug has no effect There are levels at which any drug can produce harm Cultural and subcultural norms govern how much of a drug is ingested Dose-Response Curve .
Specific effects occur at specific levels of ingestion.
Synergy User experimentation Route of Administration Certain drugs, certain ways only. Cultural Norms, Group behaviors, and practicality. Variations in these contingent elements work to produce for particular individuals in particular social contexts the effects that come to be associated with particular substances. We will be studying the variety of substances defined as drugs based on these effects and the classification schemes developed to organize and direct our understanding of drugs.