What does the abbreviation 'ad' refer to in medical prescriptions?

The abbreviation 'ad' in medical prescriptions is derived from the Latin phrase "auris dextra," which translates to "right ear." This designation is commonly used in prescriptions involving ear drops or other treatments specific to the right ear, ensuring that the patient understands the precise location for administration.

Understanding this abbreviation is crucial for ensuring correct medication application, especially in treatments tailored for specific anatomical regions. The other options refer to different abbreviations: "both ears" typically uses "au," "left ear" uses "as," and "both eyes" utilizes "ou," which are distinct from 'ad.' This clarity helps prevent medication errors and ensures the correct administration of treatments.