What can an unintended outcome of medication lead to?

An unintended outcome of medication, often referred to as an adverse effect or side effect, occurs when a medication causes effects that are not the primary purpose of the treatment. These effects can range from mild to severe and may include symptoms like nausea, dizziness, or allergic reactions. Such side effects can negatively impact a patient's well-being and may even require additional medical intervention. Therefore, option C accurately describes the potential consequences of medication that does not lead to the desired outcomes, emphasizing the importance of monitoring and managing any adverse effects when medications are prescribed.

The other outcomes listed do not typically result from unintended medication effects. Enhanced effectiveness of another treatment is a beneficial interaction between medications, while improvement in overall health and immediate recovery from illness suggests positive results that are not linked with unintended consequences.