Definition of Adverse reaction
Adverse reaction: In pharmacology, any unexpected or dangerous reaction to a drug. An unwanted effect caused by the administration of a drug. The onset of the adverse reaction may be sudden or develop over time.
Also called an adverse drug event (ADE), adverse drug reaction (ADR), adverse effect or adverse event.
Source: MedTerms™ Medical Dictionaryhttp://www.medterms.com/script/main/art.asp?articlekey=26227
Last Editorial Review: 6/14/2012
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