What defines a legend drug?

A legend drug is specifically defined as a medication that requires a prescription due to its potential for misuse, side effects, or because it needs to be used under the supervision of a licensed healthcare provider. The designation of "legend" often comes from the requirement that certain drugs carry the label stating they are only to be dispensed upon a prescription, indicating that they are controlled substances or have higher risks associated with their use. This classification helps ensure that patients receive appropriate medical guidance and monitoring when using these medications, which can include both common pharmaceuticals and controlled substances.

In contrast, the other choices relate to medications or substances that do not require a prescription or are not regulated in the same manner; thus, they do not meet the definition of a legend drug.