Define "adverse drug reaction."

The definition of "adverse drug reaction" refers specifically to an undesirable or harmful reaction that occurs when a medication is administered at normal or therapeutic doses. This means that the reaction is directly related to the use of the drug, rather than being an expected outcome or a result of incorrect dosing.

Adverse drug reactions can vary widely in severity, ranging from mild effects to serious, life-threatening responses. Identifying and understanding these reactions are crucial for ensuring patient safety. The classification emphasizes that adverse reactions occur within the scope of therapeutic use, distinguishing them from situations where a medication is misused or overdosed, which would lead to different considerations.

Other choices provided do not align with this definition. A positive response to medication implies a beneficial effect, which does not relate to the adverse reactions associated with drug administration. Common side effects are expected outcomes and are typically manageable, while stating that an adverse reaction is a rare occurrence does not capture the essence of the term since adverse reactions can occur frequently or infrequently, regardless of their prevalence.