Medical 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 Dictionary
Last Editorial Review: 5/13/2016
Medical Dictionary Definitions A - Z
Search Medical Dictionary