Which is a requirement for the warning legend on dangerous drugs as per federal law?

The requirement for the warning legend on dangerous drugs, as specified by federal law, is that it must include a caution stating that federal law prohibits dispensing without a prescription. This is rooted in the essential goal of regulating the distribution and use of controlled substances. The caution serves as a key reminder to pharmacists and healthcare providers about the legal framework that restricts access to certain medications, emphasizing the importance of a legitimate prescription before a patient can acquire the drug.

This warning is put in place to help prevent misuse and abuse of dangerous drugs, ensuring that they are used safely and only when necessary, under the guidance of a qualified healthcare professional. By highlighting the prescription requirement, the caution helps maintain strict control over substances that could pose a risk to public health if misused.

The other options do not accurately represent the legal requirements associated with dangerous drugs. For instance, while it is true that some drugs have restrictions, the specifics involving over-the-counter sales or packaging do not apply under the same legal framework as the necessity for a prescription.