An adverse drug reaction (abbreviated ADR) is a term to describe the unwanted, negative consequences sometimes associated with the use of medications. It is more precise than, and usually preferred in the medical field, over the term "side-effect" as these purported "side"-effects may sometimes be therapeutically-useful.
While ADR is probably the most precise term to describe the concept, it is not widely used in the community since it may be perceived as jargon and because of the negative-associations with the term "drug". Alternative terms with equivalent meaning to ADR include: side-effect, adverse event, adverse effect, etc.
See Adverse effect (medicine) for the main article on this subject, which includes adverse effects of drugs.
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