In the field of pharmacology, potency is a measure of drug activity expressed in terms of the amount required to produce an effect of given intensity. A highly potent drug (e.g., fentanyl, alprazolam, risperidone) evokes a given response at low concentrations, while a drug of lower potency (meperidine, diazepam, ziprasidone) evokes the same response only at higher concentrations. Higher potency does not necessarily mean more side effects.
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