Adverse drug reaction: An adverse drug reaction is an unwanted or harmful reaction suspected to be caused by a medicine. It can be mild, such as dizziness, or more serious, such as severe mood or liver-related problems.
Gives patients the language used in safety reporting and clinical review.
NICE and GMC both point to MHRA Yellow Card reporting for adverse reactions.
Not every new symptom is definitely caused by the medicine, but suspected reactions should still be raised promptly.