PO: Oral Route Abbreviation in Prescription Sig Codes

When you see PO on a prescription, you’re looking at one of the most common route abbreviations in pharmacy. It tells you the medication is intended for oral administration—by mouth.

What the PO Oral Route Abbreviation Means

PO stands for the Latin per os, meaning “by mouth.” In prescription sig codes, it specifies the oral route for a medication, whether the dosage form is a tablet, capsule, liquid, or oral suspension. You’ll see it written as Take 1 tablet PO twice daily or Amoxicillin 500 mg PO TID x7 days. The abbreviation is standard across retail and hospital settings, and it’s a core piece of prescription interpretation.

Why PO Matters for Technicians and the PTCB

As a pharmacy technician, you must accurately enter and verify the route on every prescription. The PTCB exam emphasizes prescription interpretation, including abbreviations for routes, dosage forms, and frequencies. Misreading PO as another route—such as PR (rectal) or SL (sublingual)—can lead to a wrong entry and a potential dispensing error. PO also matters when checking controlled substances: the oral route is common, and you must ensure the dosage form and instructions match the prescriber’s intent. Always confirm that the product can be administered orally and that any special instructions—like take with food—are included.

Practical PO Application Example

Imagine you receive: Prednisone 10 mg PO daily x5 days. You would enter the route as oral, select the correct tablet strength, and verify the sig reads “by mouth.” If the prescription were for a child and written as Prednisolone 15 mg/5 mL PO daily, you’d still use the oral route but choose the liquid dosage form. PO applies to the route, not the form—so your job is to connect the two correctly.

Common PO Mistake and Pro Tip

⚠️ A common mistake is assuming PO means the medication can be crushed or mixed—many oral dosage forms, like enteric-coated tablets or extended-release capsules, should not be crushed. 💡 Pro tip: always verify the dosage form and check the manufacturer’s labeling before suggesting any manipulation; when in doubt, ask the pharmacist.

Quick Reference: PO Abbreviation

PO = per os = by mouth
Route: oral (tablets, capsules, liquids, suspensions)
Example sig: Take 1 tablet PO daily
Do not confuse with PR (rectal) or SL (sublingual)
Verify dosage form before crushing or mixing

Related Concepts

Sig Codes, Route of Administration, PR (Rectal Route)