Medical prescriptions often contain a precise shorthand language to communicate instructions clearly between the prescriber and the dispenser. This practice relies on standardized abbreviations, many derived from Latin phrases that have been used for centuries in medicine. This system ensures consistency in directing the patient’s course of treatment.
The Meaning of “BD” and Its Origin
The abbreviation “BD” on a prescription stands for the Latin phrase bis die or bis in die, meaning “twice a day.” This instruction specifies that the prescribed drug should be taken two times within a 24-hour period.
This instruction is typically found on the medication label, often following the dose amount (e.g., “Take one tablet BD”). While “BID” is often the internationally preferred abbreviation, “BD” is still widely used. Regardless of the minor variation, the interpretation is consistently understood to mean two doses daily.
Understanding Other Common Frequency Terms
“BD” is part of a larger system of Latin-derived abbreviations used to specify dosing frequency. Understanding these terms is important for avoiding medication errors and ensuring a therapy is followed correctly. For instance, a prescription marked “QD” indicates the medication should be taken quaque die, which means once daily.
“TID” stands for ter in die, instructing the patient to take the medication three times a day. For medications requiring even greater frequency, “QID” is used, representing quater in die, or four times a day.
A distinct instruction is “PRN,” which stands for pro re nata, and means the medication should be taken “as needed.” This is the only term that does not mandate a specific schedule but instead ties the dose to the onset of symptoms, such as pain or nausea.
Patient Compliance and Timing Instructions
When a medication is prescribed “BD,” the effectiveness of the treatment often relies on maintaining stable drug levels in the bloodstream. For this reason, the two daily doses should ideally be spaced approximately 12 hours apart. Taking one dose in the morning and the second in the evening helps ensure that the drug concentration remains within the therapeutic range throughout the entire 24-hour cycle.
This consistent timing helps maximize the drug’s effect while minimizing the risk of side effects. If a dose is missed, a patient should first consult the specific instructions provided on the medication bottle or accompanying paperwork. A general rule of thumb is to take the missed dose as soon as it is remembered, unless it is nearly time for the next scheduled dose.
If it is closer to the time for the next dose, the missed dose should generally be skipped entirely to avoid taking two doses too close together. Never double the dose to make up for the one that was missed without first consulting a pharmacist or prescribing physician. They can provide specific guidance based on the drug’s half-life and therapeutic index.