What are side effects?

Side effects refer to the unintended secondary effects that occur when a drug is administered at normal therapeutic doses. These effects are not the primary purpose of the medication; rather, they arise as a byproduct of the drug’s pharmacological action. For example, a medication designed to relieve pain may also cause drowsiness as a secondary effect. This understanding is crucial in pharmacology, as side effects can influence a patient's adherence to a treatment regimen and overall health outcomes.

The other options do not accurately capture the definition of side effects. The notion of intended effects enhancing therapeutic results pertains to the primary actions of a medication, while harmful effects occurring only at maximum doses does not encompass the wide range of side effects that can manifest at therapeutic levels. Lastly, immediate reactions after taking a medication may refer to adverse effects or allergic responses, which are distinct from the broader category of side effects that can occur over time.