What defined which drugs require a prescription?

The 1951 Durham-Humphrey Amendment is the pivotal legislation that established the distinction between prescription and over-the-counter (OTC) medications. This amendment clarified which drugs could be dispensed only with a prescription from a licensed healthcare provider. The rationale behind this classification is often rooted in the potential need for medical supervision with certain medications due to their effects, side effects, or the potential for misuse.

Prior to this amendment, there was no clear legal differentiation between prescription and non-prescription drugs, which could lead to safety concerns. The Durham-Humphrey Amendment created a more structured and regulated approach to drug dispensation, ensuring that medications requiring professional oversight were only available through prescriptions. This has been fundamental in promoting patient safety and effective healthcare management.

The other legislative acts mentioned have their own significant roles in drug regulation but do not specifically address the definition of which drugs require a prescription. The Sherley Amendment focused on preventing false therapeutic claims, the Kefauver-Harris Amendment emphasized drug efficacy and safety in the wake of the thalidomide tragedy, and the Poison Prevention Packaging Act aimed to protect children from medication-related hazards through child-resistant packaging.