Sig Codes, Refill Requests, DAW Codes and DUR Alerts

Prescription Directions, Sig Codes, and Safe Labeling Standards

The abbreviation Sig originates from the Latin word signa, which instructs the dispenser to write or mark directions on the prescription label. When generating patient-label directions, a pharmacy technician must always convert medical shorthand into clear, patient-friendly language. As a standard practice, patient directions should begin with an action verb such as take, instill, or apply to clearly guide the patient on how to administer the medication.

Accurately identifying the correct route of administration is vital to preventing dispensing errors. Common route abbreviations include PO for administration by mouth or orally, SL for sublingual administration under the tongue, PR for rectal administration, TOP for topical administration to the skin, and INH for oral or nasal inhalation. Ophthalmic and otic routes require precise differentiation: ophthalmic codes specify the eyes, where OD designates the right eye, OS designates the left eye, and OU designates both eyes. Conversely, otic codes indicate the ears, where AD designates the right ear, AS designates the left ear, and AU designates both ears.

Prescriptions also specify frequency and administration timing. Standard frequency codes include BID for administration two times a day, TID for administration three times a day, and QID for administration four times a day. When an order specifies PRN, it means the medication is to be used as needed, according to its directions. Directions for PRN orders should clearly state the reason for use when it is known, and a technician should refer unclear directions to the pharmacist. Specific timing abbreviations include AC for administration before meals, PC for administration after meals, and HS for administration at bedtime. An order marked STAT means immediately; for a STAT order, the technician must prioritize processing and immediately alert the pharmacist, rather than attempting to independently administer the medication.

Patient safety requires strict adherence to medication order guidelines. The Institute for Safe Medication Practices lists U for unit and QD for daily among error-prone abbreviations that should not be used in medication orders due to the high risk of misinterpretation. In addition, numeric dosing notation must follow precise safety rules: a leading zero must always precede a decimal point value less than one, such as writing 0.5 mg, while trailing zeros following a whole number, such as 5.0 mg, must never be used due to the severe risk of ten-fold dosing errors. Finally, auxiliary labels provide supplemental administration, warning, or storage instructions directly on the prescription container to reinforce safe medication use.