Ad lib
Formal Definition
Abbreviation of the Latin phrase "ad libitum" meaning "at one's pleasure" or "as much as one wishes"; in clinical contexts, applied primarily to dietary orders (e.g., "diet ad lib" — patient may eat whatever they want, no restrictions) but also to activity orders ("ambulate ad lib" — patient may ambulate freely without restriction) and to patient behavior ("smoking ad lib" — variable interpretation); distinct from PRN (as needed, for medications) in that ad lib refers to patient autonomy over the activity itself rather than symptom-driven administration.
How It's Used on the Ward
"Ad lib" or "ad libbed" — when there are no restrictions on what the patient can eat, drink, or do activity-wise; for activity, it's usually the most permissive ambulation order (walk wherever you want, whenever you want); for diet, it's the instruction to remove dietary restrictions.
Example
""Resident on rounds to medical student: 'She's 2 days post-op from an uncomplicated lap chole, taking PO well, no nausea. Upgrade her diet to regular as tolerated, then ad lib if she tolerates breakfast without issue. Also advance activity to ad lib ambulation — she's been on the ward twice today already.'""
Clinical Context
Diet progression pattern: NPO → clear liquids → full liquids → soft/low-residue → regular → ad lib. Each step typically requires demonstrated tolerance of the prior step (no nausea/vomiting, taking adequate PO). Activity progression pattern: bedrest → up to chair → ambulate with assistance → ambulate ad lib (typically the discharge activity level). Distinct usage in psychiatry: "ad lib" for privileges (phone, visitors) — patient's social/behavioral privilege level rather than medical order. Important nuances: "ad lib" for diet rarely used in patients with severe diabetes (where controlled carbohydrate diet is preferred), renal failure (where K+ and protein restricted), or heart failure (sodium restriction). For very elderly, dysphagia risk patients, ad lib diet carefully considered with speech therapy swallow eval first.