Medical Abbreviations: "c̄" and "#" Symbol Meanings
The "c̄" (c with a horizontal line above it) is a medical abbreviation meaning "with," derived from the Latin "cum," while the "#" symbol on a prescription indicates the quantity or number of units to be dispensed.
Understanding "c̄" (c with horizontal line)
The symbol "c̄" represents the Latin word "cum" meaning "with." This abbreviation appears in medical notes and prescriptions to indicate that something is administered or occurs together with something else. However, this abbreviation is potentially dangerous and should be avoided 1, 2.
Why This Abbreviation Is Problematic
- Misinterpretation risk: The "c̄" symbol can be confused with other abbreviations or symbols, particularly when handwritten
- Non-intuitive meaning: Studies show that healthcare staff frequently misunderstand medication abbreviations, with some interpreting them as the opposite of their intended meaning 1
- Error potential: The use of non-standard abbreviations in prescribing and transcribing medication orders often results in misinterpretation, leading to omission errors, improper doses, or wrong drug administration 2
Safer Alternative
Write out "with" in full rather than using "c̄" to eliminate ambiguity and reduce medication errors.
Understanding "#" Symbol on Prescriptions
The "#" symbol on a prescription indicates the total number of tablets, capsules, or units to be dispensed by the pharmacy 3.
Practical Example
If a prescription reads:
- Medication: Prochlorperazine 10 mg
- Directions: Take 1 tablet every 6 hours as needed
- #30
This means the pharmacy should dispense 30 tablets total.
Clinical Context
The "#" symbol appears in standardized prescription formats where the total quantity must be clearly specified 3. This ensures:
- The pharmacy dispenses the correct amount
- The patient receives an appropriate supply duration
- Insurance and regulatory requirements are met
Key Safety Considerations
Avoid using non-intuitive abbreviations in clinical practice. Research demonstrates that 72% of nursing staff could not correctly define common medication abbreviations, and 61% incorrectly classified medications as short- or long-acting based on abbreviations 1. This creates substantial risk for medication errors, particularly with high-risk medications.
Best practice: Use complete words rather than abbreviations whenever possible to prevent potentially life-threatening medication errors 2.