According to the Institute for Safe Medication Practices (ISMP), which of the following is an approved abbreviation?

While "U" is often used as an abbreviation for "units" in medical documentation, the ISMP advises against using this abbreviation due to potential confusion with the number 0 or 4, leading to medication errors. Therefore, "U" is not an approved abbreviation according to ISMP guidelines.

The abbreviation "AD" typically stands for "right ear" in medical contexts, not "right eye." Using "AD" for the right eye could lead to confusion and errors in medication administration, hence it is not an approved abbreviation according to ISMP standards.

"AU" is a recognized medical abbreviation for "both ears" rather than "both eyes." Misinterpreting "AU" as referring to the eyes instead of the ears could result in incorrect medication dosages or administration. Therefore, "AU" is not an approved abbreviation according to ISMP guidelines.