What is the term for unintended, undesirable, and often unpredictable drug effects?

The correct term for unintended, undesirable, and often unpredictable drug effects is "adverse drug effects." This term encompasses a range of negative reactions that can occur from medication use, which may not only impact the patient's physical health but also their overall treatment experience. Adverse drug effects are significant because they can lead to additional health complications, necessitate changes in therapy, or require further medical intervention.

While "side effects" may sound similar and refer to undesirable effects, they are often predictable and may occur with regular use of a medication, whereas adverse drug effects typically denote more severe, unexpected reactions. "Therapeutic effects" focus on the intended beneficial outcomes of a drug, and "expected effects" pertain to what treatment aims to achieve based on its design. Thus, understanding the nuanced difference between these terms is crucial in clinical nursing to ensure patient safety and effective treatment planning.