The PCN medical abbreviation most often means penicillin, the antibiotic, and you will see it most of all in allergy lists, as in "PCN allergy" or "Allergies: PCN." In urology and radiology, PCN has a second, unrelated meaning: percutaneous nephrostomy, a small tube placed through the skin of the back to drain urine from a kidney.
The two meanings live in very different parts of a chart, so they rarely collide. An allergy banner, a medication history or an antibiotic discussion points to penicillin. A procedure note, a drainage output record or a phrase like "PCN tube" points to the kidney. Both are explained below, alongside sample lines, related terms such as NKDA and ABX, and what an allergy label does and does not mean.
At a glance
Stands for
Penicillin (most common)Other meanings
Percutaneous nephrostomy, a kidney drainage tube placed through the backWhere you see it
Allergy lists, medication histories, urology and radiology notesWritten as
PCN, pcn; PCN tube or PCN catheter for the kidney meaningRelated terms
NKDA (no known drug allergies), ABX (antibiotics)Specialty
Pharmacy and infectious disease; urology and interventional radiology
PCN medical abbreviation as penicillin
Penicillin is one of the oldest antibiotics and the head of a large family that includes amoxicillin, ampicillin, dicloxacillin and piperacillin. In notes, PCN may refer to penicillin itself, such as penicillin G or penicillin VK, or to the family as a whole, as in "PCN class antibiotics."
You will most often meet the letters on the allergy line at the top of a chart or prescription. "PCN" there means the person has reported a reaction to penicillin at some point. Clinicians then avoid that family, or look at the details of the reaction before choosing an antibiotic.
Reading a PCN allergy entry
A useful allergy entry lists the drug, the reaction and roughly when it happened. Here are a few examples and what they tell the care team.
| Entry | What it tells the team |
|---|---|
| PCN: hives as a child | Skin reaction long ago; may be worth reviewing |
| PCN: anaphylaxis | Severe reaction; penicillins strictly avoided |
| PCN: GI upset | Likely a side effect rather than a true allergy |
| PCN: unknown reaction, per mother | Reported history with no details |
ED triage: "Allergies: PCN (rash), sulfa (unknown)." The nurse enters both into the record, and the prescriber chooses an antibiotic outside the penicillin family unless the allergy is clarified. The opposite entry, NKDA, means no known drug allergies.
What a penicillin allergy label does and does not mean
Penicillin allergy is one of the most commonly reported drug allergies. Many people carry the label from a childhood rash or a reaction nobody remembers clearly, and when tested later, a large share turn out not to be allergic. Allergy specialists can test for it with skin testing and a supervised dose.
Getting an accurate label matters because penicillin family drugs are often the first choice for many infections. That said, a reader should never decide on their own that an allergy no longer applies. Testing and any change to the allergy list belong with a clinician, ideally an allergist.
PCN tube: percutaneous nephrostomy
In urology, PCN means percutaneous nephrostomy: percutaneous, through the skin, and nephrostomy, an opening into the kidney. A thin tube is placed through the back into the kidney, usually by interventional radiology using imaging, to drain urine when something blocks the normal flow, such as a stone or a tumor.
Nursing note: "R PCN draining clear yellow urine, 450 mL this shift, dressing clean and dry." Here PCN is the kidney tube on the right side, and the note tracks its output and the skin site. Nothing about antibiotics is meant.
Some patients have PCNs on both sides, written bilateral PCNs. Patients going home with a PCN tube are taught how to care for the dressing and drainage bag and when to call the care team.
Sorting penicillin from the kidney tube
| Clue in the note | Likely meaning |
|---|---|
| Allergy line, rash, hives, antibiotic choice | Penicillin |
| Right or left, output in mL, dressing, flush | Percutaneous nephrostomy |
| Radiology or urology procedure report | Percutaneous nephrostomy |
| Pharmacy profile, infection treatment plan | Penicillin |
If a line still could go either way, the author can confirm. Drug name abbreviations in general are discouraged on medication orders, so prescribers usually write the full drug name there, and PCN mostly survives in allergy lists and notes.
For students learning pharmacy and nursing abbreviations
PCN is a pharmacy abbreviation that technicians and nursing students learn early because allergy checks happen before almost every medication is dispensed or given. A safe habit is to confirm the reaction type with the patient, since "allergy" is used loosely for side effects too. Other antibiotic terms are gathered in the prescription abbreviations hub.
This explanation is general. If you think your penicillin allergy label may be wrong, raise it with your doctor or pharmacist rather than testing it yourself.
Frequently asked questions
What does PCN allergy mean?
A PCN allergy means the person has a recorded allergy to penicillin. Care teams usually avoid penicillin and related antibiotics, such as amoxicillin, unless the allergy is reviewed by a clinician.
What is the medical abbreviation for penicillin?
PCN is the common abbreviation for penicillin, especially in allergy lists. Orders for the medicine itself usually spell out the drug name.
What is a PCN tube?
A PCN tube is a percutaneous nephrostomy tube, a thin drain placed through the back into a kidney to drain urine when the normal path is blocked.
Is amoxicillin a PCN drug?
Yes. Amoxicillin belongs to the penicillin family, so a PCN allergy entry usually means amoxicillin is avoided too unless a clinician decides otherwise.
Can a penicillin allergy go away?
Many people labeled allergic to penicillin are not allergic when tested later. Testing is done by clinicians, often allergy specialists, and should not be tried at home.