Which of the following indicates the right ear in medication instructions?

In medication instructions, the abbreviation used to indicate the right ear is "ad," which stands for "auris dextra." This term is derived from Latin, where "auris" means ear, and "dextra" means right. Therefore, when a prescription or medication label specifies "ad," it is directing that the medication should be administered in the right ear.

Understanding medical abbreviations is crucial in the pharmacy setting to ensure proper administration of medications. The other options represent different ear-related instructions: "as" refers to the left ear (auris sinistra), "au" indicates both ears (auris utraque), and "bu" is not a standard abbreviation in this context. Recognizing these distinctions is essential for safe and accurate patient care.