When a medication is prescribed "ad lib," what does it indicate?

When a medication is prescribed "ad lib," it indicates that the patient can take the medication as desired. This term comes from the Latin phrase "ad libitum," which translates to "at one's pleasure." It allows for flexibility in administration, meaning patients can take the medication whenever they feel it is necessary, within safe limits. This is particularly common for medications that alleviate pain or for those that are not critical to take at strict intervals.

In contrast, the other options present specific dosing schedules or immediate administration, which do not align with the intent of "ad lib." This phrase emphasizes patient autonomy and individualized care based on their unique needs at the moment.