What legislation initially established guidelines for drug safety and efficacy in the marketplace?

The Kefauver-Harris Amendment of 1962 was pivotal in establishing comprehensive guidelines for drug safety and efficacy. This legislation emerged in response to growing concerns about the safety of medications following incidents such as the thalidomide tragedy, where a drug caused severe birth defects.

Prior to this amendment, the Food, Drug, and Cosmetic Act of 1938 had required drugs to be proven safe before marketing, but it did not mandate proof of efficacy. The Kefauver-Harris Amendment changed that by requiring drug manufacturers to provide substantial evidence for the effectiveness of their drugs as well as for their safety. This shift emphasized the importance of rigorous clinical testing and regulated the processes for drug approval.

Additionally, the amendment authorized the FDA to have greater oversight in the approval process and required that all drugs be labeled with adequate directions for use, ensuring transparency and consumer safety. Therefore, this legislation laid the foundation for the modern regulatory processes that govern pharmaceuticals today, solidifying its significance in the history of drug regulation.