Key Takeaways
- Valid prescriptions must include patient name, drug name, strength, quantity, directions, prescriber information, and date.
- Sig codes are abbreviations for prescription directions (e.g., BID = twice daily, PRN = as needed).
- DAW (Dispense As Written) codes indicate generic substitution preferences, with DAW-0 allowing substitution.
- Schedule II prescriptions require written prescriptions and cannot be refilled.
- Always verify prescription validity including prescriber authority and prescription age limits.
Prescription Intake and Interpretation
Quick Answer: A valid prescription requires patient name, drug name/strength/quantity, directions (sig), prescriber info with DEA number for controls, and date written. Pharmacy technicians must verify all elements and understand sig codes to process prescriptions accurately.
Elements of a Valid Prescription
Every prescription must contain these essential elements:
| Element | Description | Example |
|---|---|---|
| Patient Name | Full legal name | John Smith |
| Patient Address | Required for controlled substances | 123 Main St, City, ST 12345 |
| Date Written | When prescription was issued | 01/21/2026 |
| Drug Name | Generic or brand name | Lisinopril OR Prinivil |
| Strength | Dose per unit | 10 mg |
| Quantity | Amount to dispense | #30 (thirty) |
| Directions (Sig) | How to take | Take 1 tablet by mouth daily |
| Refills | Number authorized | Refill x 3 |
| Prescriber Info | Name, address, phone, NPI | Dr. Jane Doe, MD |
| DEA Number | Required for controlled substances | AD1234563 |
| Prescriber Signature | Required for written Rx | Handwritten or e-signature |
Common Sig Codes and Abbreviations
Sig codes are Latin-based abbreviations that describe how medications should be taken:
Frequency Abbreviations
| Abbreviation | Meaning | Full Latin |
|---|---|---|
| QD or QAM | Once daily (morning) | Quaque die |
| BID | Twice daily | Bis in die |
| TID | Three times daily | Ter in die |
| QID | Four times daily | Quater in die |
| Q4H | Every 4 hours | Quaque 4 hora |
| Q6H | Every 6 hours | Quaque 6 hora |
| Q8H | Every 8 hours | Quaque 8 hora |
| Q12H | Every 12 hours | Quaque 12 hora |
| QHS or HS | At bedtime | Hora somni |
| PRN | As needed | Pro re nata |
| STAT | Immediately | Statim |
| AC | Before meals | Ante cibum |
| PC | After meals | Post cibum |
Route Abbreviations
| Abbreviation | Meaning |
|---|---|
| PO | By mouth (oral) |
| SL | Sublingual (under tongue) |
| PR | Per rectum |
| IM | Intramuscular |
| IV | Intravenous |
| SC or SQ or SubQ | Subcutaneous |
| TOP | Topical |
| INH | Inhalation |
| OU | Both eyes |
| OD | Right eye |
| OS | Left eye |
| AU | Both ears |
| AD | Right ear |
| AS | Left ear |
Dosage Form Abbreviations
| Abbreviation | Meaning |
|---|---|
| TAB | Tablet |
| CAP | Capsule |
| SOL | Solution |
| SUSP | Suspension |
| CR/ER/XR/XL | Controlled/Extended release |
| DR | Delayed release |
| SUPP | Suppository |
| GTT | Drop(s) |
| AMP | Ampule |
| INJ | Injection |
Example Sig Interpretation
Rx: Lisinopril 10mg #30 Sig: i tab PO QD
Translation: Take one (i) tablet by mouth (PO) once daily (QD)
Rx: Amoxicillin 500mg #21 Sig: i cap PO TID x 7 days
Translation: Take one (i) capsule by mouth (PO) three times daily (TID) for 7 days
DAW (Dispense As Written) Codes
DAW codes indicate whether generic substitution is allowed:
| DAW Code | Meaning | Who Decides |
|---|---|---|
| DAW-0 | No product selection indicated | Pharmacist may substitute |
| DAW-1 | Substitution not allowed by prescriber | Prescriber requires brand |
| DAW-2 | Patient requests brand | Patient prefers brand |
| DAW-3 | Pharmacist selects brand | Pharmacist decision |
| DAW-4 | Generic not in stock | Supply issue |
| DAW-5 | Brand dispensed, priced as generic | Billing consideration |
| DAW-6 | Override | State law/regulation |
| DAW-7 | Brand mandated by law | Legal requirement |
| DAW-8 | Generic not available | Manufacturer issue |
| DAW-9 | Other | Documented reason |
Exam Tip: DAW-0 means the pharmacist CAN substitute with a generic. DAW-1 means the prescriber requires brand only. DAW-2 means the patient requested brand name.
Prescription Verification Steps
- Verify patient identity - Confirm name, DOB, address, allergies
- Check prescription validity - Date, completeness, authenticity
- Verify prescriber authority - Licensed, DEA valid for controls
- Screen for interactions - Drug-drug, drug-disease, allergies
- Confirm insurance coverage - Prior authorization if needed
- Perform DUR - Drug utilization review
- Have pharmacist verify - Final check before dispensing
A prescription reads "Metformin 500mg, Sig: i tab PO BID." How should this be interpreted?
Which DAW code indicates that the PRESCRIBER has specifically requested that no generic substitution be made?
A prescription for a Schedule II controlled substance was written 45 days ago. In most states, what should the pharmacy technician do?