PRN Meaning: What PRN Means on a Prescription

Quick answer

PRN means as needed. It comes from the Latin pro re nata. On a prescription or hospital order, a PRN medicine is given only when a set need comes up, such as pain, and not on a fixed schedule. In a job ad, a PRN nurse works shifts as needed instead of a set schedule.

Best forNursing and pharmacy students, caregivers, and anyone who sees PRN on a prescription, a chart or a job ad.

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Medical Abbreviations - Essential Clinical Shorthand

The medical abbreviations you actually see on charts, orders, and prescriptions, expanded in plain English. Covers prescription frequency and routes, chart and history shorthand, vital signs, labs and imaging, departments, and provider titles.

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How to read a PRN order: 1 tab PO q4h PRN pain

A PRN order reads left to right: how much, how, how often and why. This one reads as 1 tablet by mouth every 4 hours as needed for pain.

Medical Abbreviations	Pronunciation	Meaning
1 tab	one tab	One tablet
PO	P-O	By mouth
q4h	Q-4-H	Every 4 hours
PRN	P-R-N	As needed
pain	pain	The reason to give it

PRN vs scheduled: set times or only when needed

A scheduled medicine is given at set times. A PRN medicine is given only when the need on the order comes up. Some orders join the two, like q6h PRN.

Medical Abbreviations	Pronunciation	Meaning
BID	B-I-D	Twice a day, on a schedule
q6h	Q-6-H	Every 6 hours, on a schedule
q6h PRN	Q-6-H P-R-N	Every 6 hours, as needed
HS PRN	H-S P-R-N	At bedtime, as needed
ATC	A-T-C	Around the clock
STAT	stat	Right away

Codes you often see next to PRN

These short forms show up in the same orders. Like PRN, SOS and ad lib come from Latin.

Medical Abbreviations	Pronunciation	Meaning
SOS	S-O-S	If there is a need (from si opus sit)
ad lib	ad lib	Freely, as much as wanted
NTE	N-T-E	Not to exceed
NMT	N-M-T	Not more than
SL	S-L	Under the tongue
ud	U-D	As directed

PRN at work: a PRN nurse works as needed

In hiring, PRN has a second meaning. A PRN nurse is a fully licensed nurse who picks up shifts as needed. This is also called per diem work.

Medical Abbreviations	Pronunciation	Meaning	Listen
PRN nurse	P-R-N nurse	A nurse who works shifts as needed
per diem	per DEE-um	By the day; another name for PRN work

Frequently asked questions

What does PRN stand for?

PRN stands for pro re nata, a Latin phrase. In medicine it means as needed. MedlinePlus defines PRN as "as needed" and notes that your doctor may write it on your prescription.

What does PRN mean in nursing?

It has two uses. On a medicine order, PRN means the medicine is given only when the need on the order comes up. In hiring, a PRN nurse works shifts as needed instead of a fixed schedule.

What does q4h PRN mean?

q4h PRN means every 4 hours as needed. The q stands for every and the h stands for hour.

Is PRN the same as SOS?

Nearly. SOS comes from the Latin si opus sit, which means if there is a need. Both mean the medicine is given only when it is needed.

What does PRN mean on my pill bottle?

It means the medicine is for use only when you need it, for the reason on the label, and not on a set schedule. Ask your pharmacist how often you can take it.

Where do these meanings come from?

We checked each one against two lists: the MedlinePlus list of common abbreviations and a prescription list from the State of Minnesota. The PRN nurse meaning comes from Nurse.org.