What does "adverse drug reaction" refer to?

The term "adverse drug reaction" specifically refers to an unwanted or harmful reaction that occurs after the administration of a medication. This definition encompasses a range of negative effects, which can vary in severity and impact on the patient's health. Adverse drug reactions can result from the pharmacological properties of the drug, interactions with other medications, or individual patient factors like allergies or genetic predispositions.

In contrast to the other options, an adverse drug reaction does not imply a positive outcome, nor does it refer to expected minor side effects. Such side effects are usually anticipated as part of the therapeutic process and are often documented in medication information, rather than being classified as adverse reactions. An increase in medication efficacy also does not align with the concept of an adverse drug reaction, as it focuses on negative outcomes rather than therapeutic benefits. Understanding this definition is crucial for safe medication administration and effective patient care.