Medical terminology and sig codes
Sig codes are standard prescription abbreviations commonly used in pharmacies and by healthcare providers. The term Sig comes from the Latin word Signetur, meaning “let it be labeled.”
Most Sig codes tell you:
- how to use a medication
- how much to use
- when to use it
- how often to use it
Sig codes may be written in uppercase or lowercase, as long as the letters are used correctly. Because these are standard codes, they help prescriptions get processed and filled more quickly. However, errors can happen if someone isn’t trained to interpret the abbreviations or if a handwritten prescription is hard to read.
Table showing Sig codes denoting how often to take a medication
| Sig code | Meaning |
|---|---|
| prn | As needed |
| STAT | Immediately |
| 2STAT | Take 2 (tablets, capsules, etc.) immediately |
| q | Every |
| qd | Once a day or every day |
| qh | Every hour |
| q4h | Every 4 hours |
| bid | Twice daily |
| tid | Three times a day |
| qid | Four times a day |
| qod | Every other day |
| 1XD | One time a day |
| AM | In the morning |
| PM | In the evening |
| qAM | Every morning |
| AMPM | In the morning and evening |
| hs | At bedtime |
| ASAP | As soon as possible |
| c | With |
| UD | As directed |
| QS | Quantity sufficient |
Table showing Sig codes denoting routes to take a medication
| Sig code | Route |
|---|---|
| ad | In right ear |
| as | In left ear |
| au | In both ears |
| od | In right eye |
| os | In left eye |
| ou | In both eyes |
| po | By mouth |
| PR | Per rectal |
| im | Intramuscularly |
| pv | Per vaginally |
| sl | Sublingual |
| en | In each nostril |
Table showing other common abbreviations
| Abbreviation | Meaning |
|---|---|
| gtt(s) | Drop(s) |
| tab | Tablet |
| supp | Suppository |
| SS | One-half |
| S/S | Swish and swallow |
| pc | After meals |
| mg | Milligram |
| ml | Milliliter |
| tbsp | Tablespoon (15 ml) |
| tsp | Teaspoon (5ml) |
| cap | Capsule |
| INH | Inhale |
| INJ | Inject |
| SR | Sustained release |
| XR | Extended-release |
| NPI | National provider identifier |
Examples of how to use the Sig codes and abbreviations
-
1 tab po daily - take one tablet by mouth daily.
-
1 tsp po TID - take one teaspoon by mouth three times a day.
-
1 tbsp po q6h - take one tablespoon by mouth every six hours.
-
1-2 gtts qd ad - instill 1-2 drops daily in the right ear.
-
1 tab pr qd prn - insert one tablet rectally daily as needed.