What action is essential when giving nystatin as a suspension?

When administering nystatin as a suspension, shaking the bottle well prior to administration is essential. This action ensures that the medication is evenly distributed within the liquid, allowing for a consistent dose to be delivered to the patient. Nystatin oral suspensions contain active ingredients that may settle at the bottom of the bottle, and only by shaking the bottle can one ensure that the patient receives the correct concentration of the medication.

The other options, while they may have their own relevance in different contexts, do not provide the same critical importance as shaking the suspension. Some medications do not require refrigeration and can be stored at room temperature, while administering with food can affect the absorption of certain drugs but is not a requirement for nystatin. Additionally, while using a syringe is a precise method of measuring liquid medications, the most vital step before any administration is to ensure the liquid is properly mixed.