The Latin Roots of Prescription Abbreviations
Prescription abbreviations are derived from Latin phrases that were once universally understood by medical professionals. While electronic prescriptions are now common, these traditional terms are still widely used, especially in handwritten notes or older medical records. Understanding the origin of these abbreviations can help demystify the instructions and reduce the risk of misinterpretation.
- OD (omne in die): This Latin phrase translates to 'once daily'. It indicates that the medication should be taken one time every 24 hours. The timing is often flexible unless specified otherwise, but consistency is key for maintaining a steady level of the drug in the bloodstream.
- BD (bis in die): Derived from the Latin phrase 'bis in die,' this means 'twice daily'. A BD dose is typically taken every 12 hours to maintain a consistent drug level throughout the day and night. It is important to note that the abbreviation BID is also commonly used for 'twice daily' and is sometimes clearer to read, especially in handwritten prescriptions where a 'B' can sometimes be mistaken for an 'O'.
Why Correct Interpretation is Crucial for Patient Safety
Getting your medication frequency right is not just about following instructions; it's about your health and safety. Taking medication too often can lead to an overdose, causing harmful side effects, while taking it too infrequently can reduce its therapeutic effect, rendering the treatment ineffective. Common errors include mistaking OD for BD, which doubles the dosage, or misreading handwritten abbreviations. For example, a poorly written QD (once daily) can look like QID (four times daily), a common and dangerous error.
Other Common Prescription Abbreviations
Pharmacology uses a wide range of shorthand to communicate dosing instructions efficiently. Beyond BD and OD, here are some other abbreviations you might encounter on a prescription:
- TID (ter in die): Three times a day, typically spaced at 8-hour intervals.
- QID (quater in die): Four times a day, generally taken every 6 hours.
- PRN (pro re nata): As needed, meaning the medication is not on a set schedule but should be taken only when symptoms require it, such as for pain relief.
- HS (hora somni): At bedtime.
- AC (ante cibum): Before meals.
- PC (post cibum): After meals.
- STAT (statim): Immediately.
- PO (per os): By mouth.
- QOD (quaque altera die): Every other day. Note that this abbreviation can be particularly confusing and is on the list of dangerous abbreviations, as it can be easily mistaken for
QDorQID.
The Ambiguity of 'OD': A Specific Caution
One of the most dangerous ambiguities in prescription shorthand involves 'OD'. While it stands for 'once daily' in general medication frequency, in ophthalmology, OD stands for 'oculus dexter,' which means 'right eye'. This is a critical distinction, especially for liquid medications like eye drops. A pharmacist receiving a prescription for eye drops marked 'OD' will know to dispense it for the right eye. However, a patient might misread it, potentially administering an oral liquid medication into their eye if the preparation is similar or if instructions are unclear. This highlights the importance of asking for clarification and ensuring all details on the prescription label are understood.
A Comparison of BD and OD
To simplify the differences, this table outlines the key aspects of BD and OD dosing frequencies:
| Aspect | BD (Bis in Die) | OD (Omne in Die) |
|---|---|---|
| Frequency | Twice daily | Once daily |
| Latin Meaning | Twice in a day | Once in a day |
| Dosage Interval | Roughly every 12 hours | Roughly every 24 hours |
| Timing Example | 8 AM and 8 PM | 9 AM each day |
| Key Consideration | Maintains a consistent drug level throughout the 24-hour period | Provides a single, convenient daily dose |
| Safety Note | Sometimes written as BID, which can be less prone to misreading than BD. | Can be confused with 'oculus dexter' (right eye), especially for liquid meds. |
Best Practices for Patients
Adherence to the prescribed regimen is vital for treatment success. As a patient, you can empower yourself by following these practices:
- Always Ask for Clarification: Do not leave the pharmacy with any doubt. If you are unsure about what BD and OD stand for in prescriptions or any other instruction, ask the pharmacist for a full explanation.
- Request Printed Labels: For handwritten prescriptions, request that the pharmacist provides a printed, clearly worded label that spells out instructions in plain language, such as 'Take one tablet twice a day'.
- Use Tools for Organization: Utilize pill organizers with compartments for different days and times to help keep track of your doses.
- Maintain a Medication List: Keep a comprehensive list of all your medications, including the drug name, dosage, frequency, and purpose. Share this with all your healthcare providers.
- Report Errors: If you suspect a medication error, inform your doctor or pharmacist immediately. Reporting can help prevent future incidents for other patients.
Conclusion
Successfully managing your medication regimen starts with understanding your prescription. By knowing what BD and OD stand for in prescriptions, you take an active role in your own healthcare. BD means twice daily, and OD means once daily, but potential for confusion exists, especially with the use of 'OD' for eye medication. Always prioritize clarity, ask questions, and rely on the pharmacist's expertise to ensure your safety. For more information on medication safety and preventing errors, consult reliable resources like the National Coordinating Council for Medication Error Reporting and Prevention.
