PRN
Medical abbreviation · Prescription
| Stands for | Pro re nata (as needed) |
|---|---|
| Categories | Medical |
PRN stands for Pro re nata (as needed), a prescription abbreviation.
Dosing instruction meaning a medicine is given only when a specific need arises, such as pain, nausea or wheezing, rather than on a fixed schedule. A complete PRN order states the indication, the dose and the minimum interval between doses.
Example: Ondansetron 4 mg IV q6h PRN nausea or vomiting, max 16 mg in 24 hours.
Usage notes
From Latin "pro re nata", literally "for the thing born", i.e. for the circumstance that arises. Also written p.r.n. or prn. Most hospital policies treat "PRN" without a stated reason as an incomplete order, and CMS rules restrict PRN orders for psychotropic drugs and restraints in long-term care. Pronounced as the letters P-R-N.
Related abbreviations
More prescription abbreviations
- non rep – Non repetatur (do not repeat)
- NR – No refills
- NTE – Not to exceed
- OD – Omni die (once daily)
- OJ – Orange juice
- PC – Post cibum (after meals)
- q.s. – Quantum sufficit (a sufficient quantity)
- q12h – Every 12 hours
- q1d – Once daily
- q24h – Every 24 hours
- q2h – Every 2 hours
- q2wk – Every 2 weeks
See all 77 prescription abbreviations →
This entry is for general education and is not medical advice. Abbreviation use varies between institutions; always confirm in context.