| Abbreviation | Intended meaning | Common Error |
|---|---|---|
| U | Units | Mistaken as a zero or a four (4) resulting in overdose. Also mistaken for "cc" (cubic centimeters) when poorly written. |
| µg | Micrograms | Mistaken for "mg" (milligrams) resulting in an overdose. |
| Q.D. | Latin abbreviation for every day | The period after the "Q" has sometimes been mistaken for an " I, " and the drug has been given "QID" (four times daily) rather than daily. |
| Q.O.D. | Latin abbreviation for every other day | Misinterpreted as "QD" (daily) or "QID" (four times daily). If the "O" is poorly written, it looks like a period or "I." |
| SC or SQ | Subcutaneous | Mistaken as "SL" (sublingual) when poorly written. |
| T I W | Three times a week | Misinterpreted as "three times a day" or "twice a week." |
| D/C | Discharge; also discontinue | Patient's medications have been prematurely discontinued when D/C, (intended to mean "discharge") was misinterpreted as "discontinue," because it was followed by a list of drugs. |
| HS | Half strength | Misinterpreted as the Latin abbreviation "HS" (hour of sleep). |
| cc | Cubic centimeters | Mistaken as "U" (units) when poorly written. |
| AU, AS, AD | Latin abbreviation for both ears; left ear; right ear | Misinterpreted as the Latin abbreviation "OU" (both eyes); "OS" (left eye); "OD" (right eye) |
| IU | International Unit | Mistaken as IV (intravenous) or 10(ten) |
| MS, MSO4, MgSO4 | Confused for one another | Can mean morphine sulfate or magnesium sulfate |
See the full Council Recommendation, Recommendations to Enhance Accuracy of Prescription Writing.