Which auxiliary label is often utilized for medications prescribed as needed?

The label that is often used for medications prescribed as needed is "PRN." This abbreviation stands for "pro re nata," which is a Latin term that translates to "as needed" in English. It indicates that the medication should only be taken when the patient feels it is necessary, rather than on a fixed schedule. This is particularly relevant for medications used for symptomatic relief, such as pain relievers or anxiety medications, where the patient may not require the medication continuously but only when specific symptoms arise.

The other options serve different purposes: "Take with food" advises on how to optimize the medication's absorption or reduce gastrointestinal irritation, "For external use only" specifies that a product should not be ingested and is intended for topical application, and "May cause drowsiness" alerts the patient to potential side effects related to alertness. None of these labels conveys the concept of usage based on individual need like "PRN" does.