What does the term "Adverse Drug Reaction" (ADR) refer to?

The term "Adverse Drug Reaction" (ADR) specifically refers to noxious and unintended responses to a medicinal product that occur at doses normally used for prophylaxis, diagnosis, or therapy of disease. This definition captures the essence of ADRs as they can range in severity and include a wide variety of effects.

ADRs are significant in clinical research and pharmacovigilance because they can impact patient safety and treatment efficacy. Understanding that these reactions are unintended is crucial because it highlights an aspect of risk management in medicine—striking a balance between the therapeutic benefits of a drug and its potential risks.

In contrast, responses that are only severe do not encompass the broader definition of ADRs since mild or moderate reactions can also be detrimental. Additionally, expected side effects of a medication do not qualify as ADRs since ADRs by definition imply an unexpected or unintended reaction. Finally, while all responses might be of concern in a therapeutic context, the classification of an ADR specifically pertains to the noxious nature of the response, focusing attention on safety and regulatory implications rather than merely any response.