What does "PRN" or "ad lib" indicate in terms of prescription refills?

The indication of "PRN" (pro re nata) or "ad lib" (at pleasure) in prescription refills suggests that the medication is to be taken as needed, which often implies a more flexible approach towards refills. In this context, it typically means that up to 1 year of refills is allowed for non-controlled substances, although there are regulations that prohibit refills for controlled substances beyond a certain limit. This provision aligns with the understanding that as long as the medication is required and the prescriber determines it is appropriate, the patient can receive refills without having to return to the doctor each time within that one-year period.

This reflects the pharmacist's role in assessing patient needs for ongoing therapy and complying with the prescription's intent while adhering to legal guidelines, especially differentiating between controlled and non-controlled substances.