Per Rectum Route Abbreviation: PR Sig Code for Rectal Medication Administration

When you spot PR on a prescription, you’re reading the Per Rectum Route Abbreviation—a Latin-based sig code that tells you to give medication rectally. It’s a small abbreviation with big implications for patient safety and correct dosage form selection.

What the Per Rectum Route Abbreviation Means

PR stands for per rectum, Latin for “through the rectum.” In pharmacy practice, it’s the standard abbreviation for the rectal route, used with suppositories, enemas, and rectal gels. You’ll see it in sig directions like Insert one suppository PR every 8 hours or Administer 5 mL PR once daily. The abbreviation appears on prescriptions, medication administration records (MARs), and compounding worksheets. Key fact: PR is a route abbreviation, not a dosage form—it tells you where the drug goes, not what it is.

Why It Matters for Pharmacy Technicians and the PTCB Exam

The PTCB content outline includes prescription and sig codes, so you must recognize PR instantly and distinguish it from PO (by mouth), PV (per vaginam), and p.r.n. (as needed). Misreading a route can cause serious harm—giving a rectal suppository by mouth is a sentinel event. For DEA-controlled substances, rectal formulations still require a valid prescription and correct route documentation. USP standards for nonsterile compounding (USP <795>) apply when you prepare rectal suppositories, so accurate sig translation supports compliance.

Practical Application of PR in Prescription Directions

Imagine you receive: Prochlorperazine 25 mg suppository — Insert one suppository PR every 12 hours as needed for nausea. You’d verify the dosage form is a suppository, confirm the route matches PR, and enter the sig as “Insert 1 suppository rectally every 12 hours as needed.” For a rectal gel like Diazepam 10 mg PR, you’d ensure the caregiver understands rectal administration. Always translate PR to “rectally” on the patient label when possible for clarity.

Common Mistake and Pro Tip for PR Sig Codes

⚠️ A frequent error is confusing PR with p.r.n. (as needed) when the “n” is missing or illegible—or mixing it up with PV (per vaginam). 💡 Pro tip: When you see PR, say “rectally” out loud as you verify the order, and write “rectal” on the label instead of leaving just the abbreviation. That simple habit catches route errors before they reach the patient.

Quick Reference: Per Rectum Route Abbreviation

PR = per rectum (rectal route)
Common sig: Insert 1 supp PR BID or PRN
Do not confuse PR with PO (by mouth), PV (per vaginam), or p.r.n. (as needed)
Translate to “rectally” on patient labels for safety
PTCB: memorize Latin route abbreviations and their English equivalents

Related Concepts

PO (Per Os), PV (Per Vaginam), and Sig Code Abbreviations.