Definition of Adverse reaction

Reviewed on 3/29/2021

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.


Negative emotions are more powerful than positive emotions. See Answer

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