What does the term "adverse drug reaction" mean?

The term "adverse drug reaction" refers specifically to unwanted or harmful reactions that occur as a result of taking a medication. These reactions can vary in severity and may manifest in various ways, including physical symptoms or changes in health status. This definition encompasses a wide range of potential effects, not just those that are expected or typical, as would be the case with expected reactions to medication.

While allergic reactions may lead to adverse effects and could fall under the umbrella of adverse drug reactions, not all adverse drug reactions are allergic in nature. The term is broader and includes any negative outcomes that stem from medication use. Furthermore, reactions due to drug interactions are also notable but do not encompass the entirety of what qualifies as an adverse drug reaction. Therefore, identifying unwanted or harmful reactions as the essence of the term captures its significance in pharmacology and patient safety.