The PR medical abbreviation has several standard meanings, and the right one depends on where it appears: per rectum in a medicine order, the PR interval on a heart tracing, partial response in a cancer report, and progesterone receptor in a breast cancer pathology report.
Because the letters are so short and so widely used, the setting is everything. A pharmacy label line, an EKG report, and an oncology note each use PR in a completely different way. Below, each meaning is explained with a sample line and the clues that point to it.
At a glance
Stands for
Per rectum (by the rectal route)Other meanings
PR interval (heart); partial response (oncology); progesterone receptor (pathology); pulse rateLatin origin
Per rectum, through the rectumNormal PR interval
Usually about 0.12 to 0.20 seconds in adultsSafer to write
Rectally, when writing a medicine order by handDo not confuse with
PR as a pharmacy and nursing abbreviation
As a pr pharmacy abbreviation, PR means the medicine is given by the rectal route, usually as a suppository or an enema. This route helps when someone cannot swallow, is vomiting, or must stay NPO. Common examples include acetaminophen for fever and some anti nausea medicines.
Hospital order: "Acetaminophen 650 mg PR q6h PRN fever." One rectal suppository may be given every six hours if needed for fever. The line is a format example, not a dosing guide.
As a pr nursing abbreviation, nurses also write PR in exam notes, such as "bleeding PR," meaning blood passed from the rectum, or in a DRE finding. On printed labels, pharmacies spell it out as rectally so patients are not left to decode it.
The PR interval: the heart meaning
Searches for the pr medical abbreviation heart meaning point to the PR interval on an electrocardiogram. It is the time from the start of the P wave, when the upper chambers contract, to the start of the QRS complex, when the lower chambers contract. In adults it usually lasts about 0.12 to 0.20 seconds, or 120 to 200 milliseconds.
A long PR interval suggests the electrical signal is slowed between the chambers, called first degree heart block. A short one can point to an extra electrical pathway. Readings are always interpreted by a clinician with the full tracing in view.
Partial response in oncology notes
In cancer care, the pr medical abbreviation partial response describes a tumor that has shrunk but not gone away. Under the widely used solid tumor response criteria, a partial response usually means the total size of the measured tumors has decreased by at least 30 percent from the starting scans.
| Term | Short form | General meaning |
|---|---|---|
| Complete response | CR | No measurable disease left |
| Partial response | PR | Meaningful shrinkage, disease still present |
| Stable disease | SD | Neither enough shrinkage nor enough growth |
| Progressive disease | PD | Tumors have grown or new ones appeared |
So a pr medical abbreviation oncology note reading "PR after 4 cycles" means treatment is working to a meaningful degree.
Progesterone receptor in breast cancer reports
In breast cancer pathology, the pr medical abbreviation progesterone receptor meaning appears with ER, the estrogen receptor. Lab staining shows whether tumor cells carry these receptors. A report might say "ER positive, PR positive, HER2 negative." Receptor positive cancers may respond to hormone blocking treatments. Together, ER and PR status is often summed up as hormone receptor status, explained on the HR page.
How to tell which PR medical abbreviation meaning is used
| Where you see it | Example | Meaning |
|---|---|---|
| Medication order or MAR | bisacodyl 10 mg PR daily | Per rectum |
| ECG or EKG report | PR 210 ms | PR interval |
| Oncology progress note | CT shows PR | Partial response |
| Pathology report | ER+/PR+ | Progesterone receptor |
| Vital signs, some regions | PR 88 | Pulse rate |
A scrawled route gets double checked with the prescriber before any dose goes in, because swapping PR for PO, by mouth, changes everything about how the drug is given.
Questions to ask about a PR order or report
- If a medicine is ordered PR, is there a form I can swallow instead?
- On my heart tracing, is my PR interval in the usual range?
- In my cancer report, what does partial response mean for my treatment plan?
- What does my receptor status mean for treatment choices?
Short forms for other tests are collected in the tests and scans hub.
Since PR has so many uses, ask the person who wrote your note or your pharmacist to confirm what it means in your own record.
Frequently asked questions
What does PR mean on a prescription?
In a medicine order, PR means per rectum, so the medicine is given rectally, often as a suppository. Pharmacy labels usually print the word rectally instead.
What does PR mean on an EKG?
It refers to the PR interval, the time between the start of the P wave and the start of the QRS complex. In adults it is usually about 0.12 to 0.20 seconds.
What does PR mean in oncology?
In cancer reports PR means partial response, a meaningful shrinkage of measurable tumors, usually by at least 30 percent, while some disease remains.
What does ER and PR positive mean?
It means breast cancer cells have receptors for estrogen and progesterone. This hormone receptor status helps guide treatment choices.
Is PR the same as PRN?
No. PR is a route, by the rectum, while PRN means as needed. They often appear in the same line, such as PR q6h PRN.