What act revised the prescription drug legend requirement to "RX Only"?

The FDA Modernization Act of 1997 is responsible for revising the prescription drug legend requirement to "RX Only." This legislation aimed to streamline the drug approval process and enhance the safety and effectiveness of medications. One of the significant changes introduced by the Act was the simplification of the labeling requirement for prescription drugs, replacing the previously used "Caution: Federal law prohibits dispensing without a prescription" with the more concise "RX Only." This change reflects a broader push towards clearer communication regarding the status of prescription medications, making it easier for both healthcare providers and patients to understand the nature of these drugs.

The other options pertain to different aspects of drug regulation; for instance, the Kefauver-Harris Amendment primarily focused on drug efficacy and safety, the Food, Drug, and Cosmetic Act laid the groundwork for drug regulation, and the Drug Enforcement Administration Act pertains specifically to controlled substances. While all are significant in the history of drug legislation, it is the FDA Modernization Act that specifically addresses the prescription drug legend requirement.