What is durham humphrey amendment 1951?

The Durham-Humphrey Amendment of 1951 was a revision to the Federal Food, Drug, and Cosmetic Act of 1938. The Amendment established two categories of drugs: prescription and over-the-counter. It regulated the sale of prescription drugs, making it illegal to distribute these drugs without a prescription, and created a distinction between drugs that could be safely used without medical supervision and those that required a doctor's supervision. The Amendment also required that all prescription medications have adequate directions for use and warnings against possible misuse. The Durham-Humphrey Amendment was signed by President Harry S. Truman on October 26, 1951, and remained in effect until it was supplanted by the modern Prescription Drug Marketing Act in 1988.