What does the abbreviation "ad lib" mean?

The abbreviation "ad lib" is derived from the Latin phrase "ad libitum," which translates to "as desired" or "at one's pleasure." In medical contexts, this term implies that a patient can take or do something freely according to their own wishes. For example, if a healthcare provider states that a patient can have fluids "ad lib," it means the patient can drink fluids as they prefer, without a specified limit.

The other options might reflect similar concepts of patient autonomy or flexibility, but they each carry specific nuances. "As needed" indicates actions taken based on specific conditions rather than the patient's discretion. "At the discretion of the physician" would imply that a doctor controls the timing or extent of care without patient input. "Upon request" suggests that the patient must ask for something rather than doing it freely at their desire. Thus, "ad lib" emphasizes the aspect of personal choice and preference in a way that "as needed" or "upon request" do not fully capture.