What does "as needed" (PRN) indicate in medication orders?

In medication orders, "as needed," often abbreviated as PRN from the Latin "pro re nata," indicates that a medication is to be taken only when it is required or necessary, rather than on a regular schedule. This means that healthcare providers expect patients to use their judgment to decide when they need the medication based on their symptoms or condition.

For example, a patient may be prescribed pain relief medication PRN for headaches, allowing them to take the medication only when they experience pain, rather than taking it at fixed times throughout the day. This approach helps to ensure that medications are used judiciously and minimizes side effects associated with unnecessary dosing.

This concept contrasts with other options, such as taking medication at set intervals or in higher doses, which imply a more regimented and frequent use. Additionally, labeling medication as optional does not convey the directed usage that PRN signifies, which is indeed a specific indication for usage based on need, rather than chance or choice.